diff --git a/Gir_Gst.toml b/Gir_Gst.toml
index 59109de49..0c7a83f27 100644
--- a/Gir_Gst.toml
+++ b/Gir_Gst.toml
@@ -116,6 +116,11 @@ trait_name = "GstBinExt"
 name = "Gst.Bus"
 status = "generate"
 final_type = true
+    [[object.function]]
+    name = "set_sync_handler"
+    # Into<Option<_>> makes this hard to use
+    ignore = true
+
     [[object.function]]
     name = "add_signal_watch_full"
     # Priority
@@ -139,6 +144,16 @@ final_type = true
     # More convenient manual implementation
     ignore = true
 
+    [[object.function]]
+    name = "add_watch"
+    # More specific trait bounds possible for the closure
+    ignore = true
+
+    [[object.function]]
+    name = "add_watch_full"
+    # More specific trait bounds possible for the closure
+    ignore = true
+
     [[object.function]]
     name = "remove_watch"
         [object.function.return]
@@ -337,6 +352,11 @@ status = "generate"
         # It is already a Result
         nullable = false
 
+    [[object.function]]
+    name = "call_async"
+    # more specific closure type possible
+    ignore = true
+
     [[object.function]]
     name = "add_pad"
         [object.function.return]
@@ -796,6 +816,26 @@ status = "generate"
     # Wrong place
     ignore = true
 
+    [[object.function]]
+    pattern = "set_.*_function_full"
+    # More specific closure trait bounds possible
+    ignore = true
+
+    [[object.function]]
+    name = "start_task"
+    # More specific closure trait bounds possible
+    ignore = true
+
+    [[object.function]]
+    name = "sticky_events_foreach"
+    # Complex closure argument handling
+    ignore = true
+
+    [[object.function]]
+    name = "add_probe"
+    # Complex closure argument handling
+    ignore = true
+
 [[object]]
 name = "Gst.PadTemplate"
 status = "generate"
@@ -883,6 +923,11 @@ name = "Gst.Plugin"
 status = "generate"
 final_type = true
 
+    [[object.function]]
+    pattern = "register_static.*"
+    # Needs manual implementation
+    ignore = true
+
     [[object.function]]
     name = "list_free"
     # useless and unsafe
diff --git a/gstreamer-app/src/auto/app_sink.rs b/gstreamer-app/src/auto/app_sink.rs
index 06f45b84c..e69ae7c6d 100644
--- a/gstreamer-app/src/auto/app_sink.rs
+++ b/gstreamer-app/src/auto/app_sink.rs
@@ -87,7 +87,7 @@ impl AppSink {
         }
     }
 
-    //pub fn set_callbacks(&self, callbacks: /*Ignored*/&mut AppSinkCallbacks, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
+    //pub fn set_callbacks(&self, callbacks: /*Ignored*/&mut AppSinkCallbacks, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) {
     //    unsafe { TODO: call ffi::gst_app_sink_set_callbacks() }
     //}
 
@@ -160,65 +160,65 @@ impl AppSink {
 
     pub fn connect_eos<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"eos\0".as_ptr() as *const _,
-                transmute(eos_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(eos_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_buffer_list_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::buffer-list\0".as_ptr() as *const _,
-                transmute(notify_buffer_list_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_buffer_list_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_caps_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::caps\0".as_ptr() as *const _,
-                transmute(notify_caps_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_caps_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_drop_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::drop\0".as_ptr() as *const _,
-                transmute(notify_drop_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_drop_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_emit_signals_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::emit-signals\0".as_ptr() as *const _,
-                transmute(notify_emit_signals_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_emit_signals_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_eos_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::eos\0".as_ptr() as *const _,
-                transmute(notify_eos_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_eos_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_max_buffers_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-buffers\0".as_ptr() as *const _,
-                transmute(notify_max_buffers_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_buffers_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_wait_on_eos_notify<F: Fn(&AppSink) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSink) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::wait-on-eos\0".as_ptr() as *const _,
-                transmute(notify_wait_on_eos_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_wait_on_eos_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -226,42 +226,42 @@ impl AppSink {
 unsafe impl Send for AppSink {}
 unsafe impl Sync for AppSink {}
 
-unsafe extern "C" fn eos_trampoline(this: *mut ffi::GstAppSink, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn eos_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_buffer_list_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_buffer_list_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_caps_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_caps_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_drop_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_drop_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_emit_signals_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_emit_signals_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_eos_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_eos_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_max_buffers_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_max_buffers_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_wait_on_eos_trampoline(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSink) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_wait_on_eos_trampoline<F: Fn(&AppSink) + Send + Sync + 'static>(this: *mut ffi::GstAppSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-app/src/auto/app_src.rs b/gstreamer-app/src/auto/app_src.rs
index 357e1e63c..3f5fbcaa2 100644
--- a/gstreamer-app/src/auto/app_src.rs
+++ b/gstreamer-app/src/auto/app_src.rs
@@ -70,7 +70,7 @@ impl AppSrc {
         }
     }
 
-    //pub fn set_callbacks(&self, callbacks: /*Ignored*/&mut AppSrcCallbacks, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
+    //pub fn set_callbacks(&self, callbacks: /*Ignored*/&mut AppSrcCallbacks, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) {
     //    unsafe { TODO: call ffi::gst_app_src_set_callbacks() }
     //}
 
@@ -212,129 +212,129 @@ impl AppSrc {
 
     pub fn connect_enough_data<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"enough-data\0".as_ptr() as *const _,
-                transmute(enough_data_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(enough_data_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_need_data<F: Fn(&AppSrc, u32) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc, u32) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"need-data\0".as_ptr() as *const _,
-                transmute(need_data_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(need_data_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_seek_data<F: Fn(&AppSrc, u64) -> bool + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc, u64) -> bool + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"seek-data\0".as_ptr() as *const _,
-                transmute(seek_data_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(seek_data_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_block_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::block\0".as_ptr() as *const _,
-                transmute(notify_block_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_block_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_caps_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::caps\0".as_ptr() as *const _,
-                transmute(notify_caps_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_caps_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_current_level_bytes_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::current-level-bytes\0".as_ptr() as *const _,
-                transmute(notify_current_level_bytes_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_current_level_bytes_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_duration_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_emit_signals_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::emit-signals\0".as_ptr() as *const _,
-                transmute(notify_emit_signals_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_emit_signals_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_format_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::format\0".as_ptr() as *const _,
-                transmute(notify_format_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_format_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_is_live_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::is-live\0".as_ptr() as *const _,
-                transmute(notify_is_live_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_is_live_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_max_bytes_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-bytes\0".as_ptr() as *const _,
-                transmute(notify_max_bytes_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_bytes_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_max_latency_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-latency\0".as_ptr() as *const _,
-                transmute(notify_max_latency_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_latency_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_min_latency_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::min-latency\0".as_ptr() as *const _,
-                transmute(notify_min_latency_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_min_latency_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_min_percent_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::min-percent\0".as_ptr() as *const _,
-                transmute(notify_min_percent_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_min_percent_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_size_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::size\0".as_ptr() as *const _,
-                transmute(notify_size_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_size_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_stream_type_notify<F: Fn(&AppSrc) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&AppSrc) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::stream-type\0".as_ptr() as *const _,
-                transmute(notify_stream_type_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_stream_type_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -342,82 +342,82 @@ impl AppSrc {
 unsafe impl Send for AppSrc {}
 unsafe impl Sync for AppSrc {}
 
-unsafe extern "C" fn enough_data_trampoline(this: *mut ffi::GstAppSrc, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn enough_data_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn need_data_trampoline(this: *mut ffi::GstAppSrc, length: libc::c_uint, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc, u32) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn need_data_trampoline<F: Fn(&AppSrc, u32) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, length: libc::c_uint, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), length)
 }
 
-unsafe extern "C" fn seek_data_trampoline(this: *mut ffi::GstAppSrc, offset: u64, f: glib_ffi::gpointer) -> glib_ffi::gboolean {
-    let f: &&(Fn(&AppSrc, u64) -> bool + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn seek_data_trampoline<F: Fn(&AppSrc, u64) -> bool + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, offset: u64, f: glib_ffi::gpointer) -> glib_ffi::gboolean {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), offset).to_glib()
 }
 
-unsafe extern "C" fn notify_block_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_block_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_caps_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_caps_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_current_level_bytes_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_current_level_bytes_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_duration_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_duration_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_emit_signals_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_emit_signals_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_format_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_format_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_is_live_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_is_live_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_max_bytes_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_max_bytes_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_max_latency_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_max_latency_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_min_latency_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_min_latency_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_min_percent_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_min_percent_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_size_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_size_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_stream_type_trampoline(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&AppSrc) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_stream_type_trampoline<F: Fn(&AppSrc) + Send + Sync + 'static>(this: *mut ffi::GstAppSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-app/src/auto/versions.txt b/gstreamer-app/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-app/src/auto/versions.txt
+++ b/gstreamer-app/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-audio/src/auto/stream_volume.rs b/gstreamer-audio/src/auto/stream_volume.rs
index 3d9de8f98..370d7da72 100644
--- a/gstreamer-audio/src/auto/stream_volume.rs
+++ b/gstreamer-audio/src/auto/stream_volume.rs
@@ -76,29 +76,29 @@ impl<O: IsA<StreamVolume>> StreamVolumeExt for O {
 
     fn connect_property_mute_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mute\0".as_ptr() as *const _,
-                transmute(notify_mute_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mute_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_volume_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::volume\0".as_ptr() as *const _,
-                transmute(notify_volume_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_volume_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_mute_trampoline<P>(this: *mut ffi::GstStreamVolume, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mute_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstStreamVolume, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<StreamVolume> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&StreamVolume::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_volume_trampoline<P>(this: *mut ffi::GstStreamVolume, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_volume_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstStreamVolume, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<StreamVolume> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&StreamVolume::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-audio/src/auto/versions.txt b/gstreamer-audio/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-audio/src/auto/versions.txt
+++ b/gstreamer-audio/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-base/src/auto/aggregator.rs b/gstreamer-base/src/auto/aggregator.rs
index a96237851..ee9bf0695 100644
--- a/gstreamer-base/src/auto/aggregator.rs
+++ b/gstreamer-base/src/auto/aggregator.rs
@@ -106,30 +106,30 @@ impl<O: IsA<Aggregator>> AggregatorExt for O {
     #[cfg(any(feature = "v1_14", feature = "dox"))]
     fn connect_property_latency_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::latency\0".as_ptr() as *const _,
-                transmute(notify_latency_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_latency_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_start_time_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::start-time\0".as_ptr() as *const _,
-                transmute(notify_start_time_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_start_time_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
 #[cfg(any(feature = "v1_14", feature = "dox"))]
-unsafe extern "C" fn notify_latency_trampoline<P>(this: *mut ffi::GstAggregator, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_latency_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstAggregator, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Aggregator> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Aggregator::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_start_time_trampoline<P>(this: *mut ffi::GstAggregator, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_start_time_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstAggregator, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Aggregator> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Aggregator::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-base/src/auto/base_sink.rs b/gstreamer-base/src/auto/base_sink.rs
index 641f0ea02..8703bcdc1 100644
--- a/gstreamer-base/src/auto/base_sink.rs
+++ b/gstreamer-base/src/auto/base_sink.rs
@@ -336,155 +336,155 @@ impl<O: IsA<BaseSink>> BaseSinkExt for O {
 
     fn connect_property_async_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::async\0".as_ptr() as *const _,
-                transmute(notify_async_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_async_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_blocksize_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::blocksize\0".as_ptr() as *const _,
-                transmute(notify_blocksize_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_blocksize_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_enable_last_sample_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::enable-last-sample\0".as_ptr() as *const _,
-                transmute(notify_enable_last_sample_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_enable_last_sample_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_last_sample_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::last-sample\0".as_ptr() as *const _,
-                transmute(notify_last_sample_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_last_sample_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_max_bitrate_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-bitrate\0".as_ptr() as *const _,
-                transmute(notify_max_bitrate_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_bitrate_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_max_lateness_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-lateness\0".as_ptr() as *const _,
-                transmute(notify_max_lateness_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_lateness_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_qos_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::qos\0".as_ptr() as *const _,
-                transmute(notify_qos_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_qos_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_render_delay_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::render-delay\0".as_ptr() as *const _,
-                transmute(notify_render_delay_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_render_delay_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_sync_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::sync\0".as_ptr() as *const _,
-                transmute(notify_sync_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_sync_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_throttle_time_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::throttle-time\0".as_ptr() as *const _,
-                transmute(notify_throttle_time_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_throttle_time_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_ts_offset_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::ts-offset\0".as_ptr() as *const _,
-                transmute(notify_ts_offset_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_ts_offset_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_async_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_async_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_blocksize_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_blocksize_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_enable_last_sample_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_enable_last_sample_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_last_sample_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_last_sample_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_max_bitrate_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_bitrate_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_max_lateness_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_lateness_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_qos_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_qos_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_render_delay_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_render_delay_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_sync_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_sync_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_throttle_time_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_throttle_time_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_ts_offset_trampoline<P>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_ts_offset_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSink, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSink> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSink::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-base/src/auto/base_src.rs b/gstreamer-base/src/auto/base_src.rs
index 3ca63ebed..d2cbadcf0 100644
--- a/gstreamer-base/src/auto/base_src.rs
+++ b/gstreamer-base/src/auto/base_src.rs
@@ -210,57 +210,57 @@ impl<O: IsA<BaseSrc>> BaseSrcExt for O {
 
     fn connect_property_blocksize_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::blocksize\0".as_ptr() as *const _,
-                transmute(notify_blocksize_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_blocksize_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_do_timestamp_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::do-timestamp\0".as_ptr() as *const _,
-                transmute(notify_do_timestamp_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_do_timestamp_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_num_buffers_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::num-buffers\0".as_ptr() as *const _,
-                transmute(notify_num_buffers_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_num_buffers_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_typefind_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::typefind\0".as_ptr() as *const _,
-                transmute(notify_typefind_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_typefind_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_blocksize_trampoline<P>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_blocksize_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSrc> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSrc::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_do_timestamp_trampoline<P>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_do_timestamp_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSrc> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSrc::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_num_buffers_trampoline<P>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_num_buffers_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSrc> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSrc::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_typefind_trampoline<P>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_typefind_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseSrc, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseSrc> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseSrc::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-base/src/auto/base_transform.rs b/gstreamer-base/src/auto/base_transform.rs
index e38682980..4e9ea4743 100644
--- a/gstreamer-base/src/auto/base_transform.rs
+++ b/gstreamer-base/src/auto/base_transform.rs
@@ -165,15 +165,15 @@ impl<O: IsA<BaseTransform>> BaseTransformExt for O {
 
     fn connect_property_qos_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::qos\0".as_ptr() as *const _,
-                transmute(notify_qos_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_qos_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_qos_trampoline<P>(this: *mut ffi::GstBaseTransform, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_qos_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBaseTransform, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<BaseTransform> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&BaseTransform::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-base/src/auto/functions.rs b/gstreamer-base/src/auto/functions.rs
index 66a5f2ce1..c4ceb86ad 100644
--- a/gstreamer-base/src/auto/functions.rs
+++ b/gstreamer-base/src/auto/functions.rs
@@ -34,11 +34,11 @@ pub fn type_find_helper_for_extension<'a, P: IsA<gst::Object> + 'a, Q: Into<Opti
     }
 }
 
-//pub fn type_find_helper_get_range<'a, P: IsA<gst::Object>, Q: IsA<gst::Object> + 'a, R: Into<Option<&'a Q>>>(obj: &P, parent: R, func: /*Unknown conversion*//*Unimplemented*/TypeFindHelperGetRangeFunction, size: u64, extension: &str) -> (Option<gst::Caps>, gst::TypeFindProbability) {
+//pub fn type_find_helper_get_range<'a, P: IsA<gst::Object>, Q: IsA<gst::Object> + 'a, R: Into<Option<&'a Q>>, S: FnMut(&gst::Object, &gst::Object, u64, u32, &gst::Buffer) -> gst::FlowReturn>(obj: &P, parent: R, func: S, size: u64, extension: &str) -> (Option<gst::Caps>, gst::TypeFindProbability) {
 //    unsafe { TODO: call ffi::gst_type_find_helper_get_range() }
 //}
 
 //#[cfg(any(feature = "v1_14_3", feature = "dox"))]
-//pub fn type_find_helper_get_range_full<'a, 'b, P: IsA<gst::Object>, Q: IsA<gst::Object> + 'a, R: Into<Option<&'a Q>>, S: Into<Option<&'b str>>>(obj: &P, parent: R, func: /*Unknown conversion*//*Unimplemented*/TypeFindHelperGetRangeFunction, size: u64, extension: S) -> (gst::FlowReturn, gst::Caps, gst::TypeFindProbability) {
+//pub fn type_find_helper_get_range_full<'a, 'b, P: IsA<gst::Object>, Q: IsA<gst::Object> + 'a, R: Into<Option<&'a Q>>, S: FnMut(&gst::Object, &gst::Object, u64, u32, &gst::Buffer) -> gst::FlowReturn, T: Into<Option<&'b str>>>(obj: &P, parent: R, func: S, size: u64, extension: T) -> (gst::FlowReturn, gst::Caps, gst::TypeFindProbability) {
 //    unsafe { TODO: call ffi::gst_type_find_helper_get_range_full() }
 //}
diff --git a/gstreamer-base/src/auto/versions.txt b/gstreamer-base/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-base/src/auto/versions.txt
+++ b/gstreamer-base/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-check/src/auto/test_clock.rs b/gstreamer-check/src/auto/test_clock.rs
index ddae351fc..a28edafc5 100644
--- a/gstreamer-check/src/auto/test_clock.rs
+++ b/gstreamer-check/src/auto/test_clock.rs
@@ -127,9 +127,9 @@ impl TestClock {
 
     pub fn connect_property_clock_type_notify<F: Fn(&TestClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&TestClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::clock-type\0".as_ptr() as *const _,
-                transmute(notify_clock_type_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_clock_type_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -143,7 +143,7 @@ impl Default for TestClock {
 unsafe impl Send for TestClock {}
 unsafe impl Sync for TestClock {}
 
-unsafe extern "C" fn notify_clock_type_trampoline(this: *mut ffi::GstTestClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&TestClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_clock_type_trampoline<F: Fn(&TestClock) + Send + Sync + 'static>(this: *mut ffi::GstTestClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-check/src/auto/versions.txt b/gstreamer-check/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-check/src/auto/versions.txt
+++ b/gstreamer-check/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-editing-services/src/auto/asset.rs b/gstreamer-editing-services/src/auto/asset.rs
index 7e0ca33fd..8036cd71f 100644
--- a/gstreamer-editing-services/src/auto/asset.rs
+++ b/gstreamer-editing-services/src/auto/asset.rs
@@ -52,13 +52,12 @@ impl Asset {
     pub fn request_async<'a, P: IsA<gio::Cancellable> + 'a, Q: Into<Option<&'a P>>, R: FnOnce(Result<Asset, Error>) + Send + 'static>(extractable_type: glib::types::Type, id: &str, cancellable: Q, callback: R) {
         assert_initialized_main_thread!();
         let cancellable = cancellable.into();
-        let user_data: Box<Box<R>> = Box::new(Box::new(callback));
-        unsafe extern "C" fn request_async_trampoline<R: FnOnce(Result<Asset, Error>) + Send + 'static>(_source_object: *mut gobject_ffi::GObject, res: *mut gio_ffi::GAsyncResult, user_data: glib_ffi::gpointer)
-        {
+        let user_data: Box<R> = Box::new(callback);
+        unsafe extern "C" fn request_async_trampoline<R: FnOnce(Result<Asset, Error>) + Send + 'static>(_source_object: *mut gobject_ffi::GObject, res: *mut gio_ffi::GAsyncResult, user_data: glib_ffi::gpointer) {
             let mut error = ptr::null_mut();
             let ret = ffi::ges_asset_request_finish(res, &mut error);
             let result = if error.is_null() { Ok(from_glib_full(ret)) } else { Err(from_glib_full(error)) };
-            let callback: Box<Box<R>> = Box::from_raw(user_data as *mut _);
+            let callback: Box<R> = Box::from_raw(user_data as *mut _);
             callback(result);
         }
         let callback = request_async_trampoline::<R>;
@@ -184,29 +183,29 @@ impl<O: IsA<Asset>> AssetExt for O {
 
     fn connect_property_proxy_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::proxy\0".as_ptr() as *const _,
-                transmute(notify_proxy_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_proxy_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_proxy_target_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::proxy-target\0".as_ptr() as *const _,
-                transmute(notify_proxy_target_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_proxy_target_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_proxy_trampoline<P>(this: *mut ffi::GESAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_proxy_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Asset> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Asset::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_proxy_target_trampoline<P>(this: *mut ffi::GESAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_proxy_target_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Asset> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Asset::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/clip.rs b/gstreamer-editing-services/src/auto/clip.rs
index 6423e8507..d5eef9021 100644
--- a/gstreamer-editing-services/src/auto/clip.rs
+++ b/gstreamer-editing-services/src/auto/clip.rs
@@ -147,29 +147,29 @@ impl<O: IsA<Clip>> ClipExt for O {
 
     fn connect_property_layer_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::layer\0".as_ptr() as *const _,
-                transmute(notify_layer_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_layer_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_supported_formats_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::supported-formats\0".as_ptr() as *const _,
-                transmute(notify_supported_formats_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_supported_formats_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_layer_trampoline<P>(this: *mut ffi::GESClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_layer_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Clip> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clip::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_supported_formats_trampoline<P>(this: *mut ffi::GESClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_supported_formats_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Clip> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clip::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/container.rs b/gstreamer-editing-services/src/auto/container.rs
index 33a0310af..08a03c749 100644
--- a/gstreamer-editing-services/src/auto/container.rs
+++ b/gstreamer-editing-services/src/auto/container.rs
@@ -101,43 +101,43 @@ impl<O: IsA<Container>> GESContainerExt for O {
 
     fn connect_child_added<F: Fn(&Self, &TimelineElement) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TimelineElement) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"child-added\0".as_ptr() as *const _,
-                transmute(child_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(child_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_child_removed<F: Fn(&Self, &TimelineElement) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TimelineElement) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"child-removed\0".as_ptr() as *const _,
-                transmute(child_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(child_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_height_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::height\0".as_ptr() as *const _,
-                transmute(notify_height_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_height_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn child_added_trampoline<P>(this: *mut ffi::GESContainer, element: *mut ffi::GESTimelineElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn child_added_trampoline<P, F: Fn(&P, &TimelineElement) + 'static>(this: *mut ffi::GESContainer, element: *mut ffi::GESTimelineElement, f: glib_ffi::gpointer)
 where P: IsA<Container> {
-    let f: &&(Fn(&P, &TimelineElement) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Container::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(element))
 }
 
-unsafe extern "C" fn child_removed_trampoline<P>(this: *mut ffi::GESContainer, element: *mut ffi::GESTimelineElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn child_removed_trampoline<P, F: Fn(&P, &TimelineElement) + 'static>(this: *mut ffi::GESContainer, element: *mut ffi::GESTimelineElement, f: glib_ffi::gpointer)
 where P: IsA<Container> {
-    let f: &&(Fn(&P, &TimelineElement) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Container::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(element))
 }
 
-unsafe extern "C" fn notify_height_trampoline<P>(this: *mut ffi::GESContainer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_height_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESContainer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Container> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Container::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/effect.rs b/gstreamer-editing-services/src/auto/effect.rs
index 38d58c6df..18030e9df 100644
--- a/gstreamer-editing-services/src/auto/effect.rs
+++ b/gstreamer-editing-services/src/auto/effect.rs
@@ -23,7 +23,7 @@ glib_wrapper! {
 }
 
 impl Effect {
-    pub fn new(bin_description: &str) -> Effect {
+    pub fn new(bin_description: &str) -> Option<Effect> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_none(ffi::ges_effect_new(bin_description.to_glib_none().0))
diff --git a/gstreamer-editing-services/src/auto/group.rs b/gstreamer-editing-services/src/auto/group.rs
index 7267d56db..2d1dd060f 100644
--- a/gstreamer-editing-services/src/auto/group.rs
+++ b/gstreamer-editing-services/src/auto/group.rs
@@ -148,71 +148,71 @@ impl<O: IsA<Group>> GroupExt for O {
 
     fn connect_property_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_in_point_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::in-point\0".as_ptr() as *const _,
-                transmute(notify_in_point_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_in_point_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_max_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-duration\0".as_ptr() as *const _,
-                transmute(notify_max_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_priority_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::priority\0".as_ptr() as *const _,
-                transmute(notify_priority_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_priority_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_start_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::start\0".as_ptr() as *const _,
-                transmute(notify_start_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_start_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_duration_trampoline<P>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Group> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Group::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_in_point_trampoline<P>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_in_point_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Group> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Group::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_max_duration_trampoline<P>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Group> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Group::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_priority_trampoline<P>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_priority_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Group> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Group::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_start_trampoline<P>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_start_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESGroup, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Group> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Group::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/layer.rs b/gstreamer-editing-services/src/auto/layer.rs
index f256bd095..876361c73 100644
--- a/gstreamer-editing-services/src/auto/layer.rs
+++ b/gstreamer-editing-services/src/auto/layer.rs
@@ -162,57 +162,57 @@ impl<O: IsA<Layer>> LayerExt for O {
 
     fn connect_clip_added<F: Fn(&Self, &Clip) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Clip) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"clip-added\0".as_ptr() as *const _,
-                transmute(clip_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(clip_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_clip_removed<F: Fn(&Self, &Clip) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Clip) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"clip-removed\0".as_ptr() as *const _,
-                transmute(clip_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(clip_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_auto_transition_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::auto-transition\0".as_ptr() as *const _,
-                transmute(notify_auto_transition_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_auto_transition_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_priority_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::priority\0".as_ptr() as *const _,
-                transmute(notify_priority_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_priority_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn clip_added_trampoline<P>(this: *mut ffi::GESLayer, clip: *mut ffi::GESClip, f: glib_ffi::gpointer)
+unsafe extern "C" fn clip_added_trampoline<P, F: Fn(&P, &Clip) + 'static>(this: *mut ffi::GESLayer, clip: *mut ffi::GESClip, f: glib_ffi::gpointer)
 where P: IsA<Layer> {
-    let f: &&(Fn(&P, &Clip) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Layer::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(clip))
 }
 
-unsafe extern "C" fn clip_removed_trampoline<P>(this: *mut ffi::GESLayer, clip: *mut ffi::GESClip, f: glib_ffi::gpointer)
+unsafe extern "C" fn clip_removed_trampoline<P, F: Fn(&P, &Clip) + 'static>(this: *mut ffi::GESLayer, clip: *mut ffi::GESClip, f: glib_ffi::gpointer)
 where P: IsA<Layer> {
-    let f: &&(Fn(&P, &Clip) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Layer::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(clip))
 }
 
-unsafe extern "C" fn notify_auto_transition_trampoline<P>(this: *mut ffi::GESLayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_auto_transition_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESLayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Layer> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Layer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_priority_trampoline<P>(this: *mut ffi::GESLayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_priority_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESLayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Layer> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Layer::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/pipeline.rs b/gstreamer-editing-services/src/auto/pipeline.rs
index 75feef662..61b8caf2a 100644
--- a/gstreamer-editing-services/src/auto/pipeline.rs
+++ b/gstreamer-editing-services/src/auto/pipeline.rs
@@ -236,85 +236,85 @@ impl<O: IsA<Pipeline>> GESPipelineExt for O {
 
     fn connect_property_audio_filter_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::audio-filter\0".as_ptr() as *const _,
-                transmute(notify_audio_filter_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_audio_filter_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_audio_sink_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::audio-sink\0".as_ptr() as *const _,
-                transmute(notify_audio_sink_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_audio_sink_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_mode_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mode\0".as_ptr() as *const _,
-                transmute(notify_mode_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mode_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_timeline_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::timeline\0".as_ptr() as *const _,
-                transmute(notify_timeline_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_timeline_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_video_filter_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::video-filter\0".as_ptr() as *const _,
-                transmute(notify_video_filter_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_video_filter_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_video_sink_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::video-sink\0".as_ptr() as *const _,
-                transmute(notify_video_sink_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_video_sink_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_audio_filter_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_audio_filter_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_audio_sink_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_audio_sink_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_mode_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mode_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_timeline_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_timeline_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_video_filter_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_video_filter_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_video_sink_trampoline<P>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_video_sink_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/project.rs b/gstreamer-editing-services/src/auto/project.rs
index 794c53fa6..95c326402 100644
--- a/gstreamer-editing-services/src/auto/project.rs
+++ b/gstreamer-editing-services/src/auto/project.rs
@@ -162,85 +162,85 @@ impl<O: IsA<Project>> ProjectExt for O {
 
     fn connect_asset_added<F: Fn(&Self, &Asset) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Asset) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"asset-added\0".as_ptr() as *const _,
-                transmute(asset_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(asset_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_asset_loading<F: Fn(&Self, &Asset) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Asset) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"asset-loading\0".as_ptr() as *const _,
-                transmute(asset_loading_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(asset_loading_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_asset_removed<F: Fn(&Self, &Asset) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Asset) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"asset-removed\0".as_ptr() as *const _,
-                transmute(asset_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(asset_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_error_loading_asset<F: Fn(&Self, &Error, &str, glib::types::Type) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Error, &str, glib::types::Type) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"error-loading-asset\0".as_ptr() as *const _,
-                transmute(error_loading_asset_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(error_loading_asset_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_loaded<F: Fn(&Self, &Timeline) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Timeline) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"loaded\0".as_ptr() as *const _,
-                transmute(loaded_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(loaded_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_missing_uri<F: Fn(&Self, &Error, &Asset) -> Option<GString> + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Error, &Asset) -> Option<GString> + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"missing-uri\0".as_ptr() as *const _,
-                transmute(missing_uri_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(missing_uri_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn asset_added_trampoline<P>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
+unsafe extern "C" fn asset_added_trampoline<P, F: Fn(&P, &Asset) + 'static>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Asset) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(asset))
 }
 
-unsafe extern "C" fn asset_loading_trampoline<P>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
+unsafe extern "C" fn asset_loading_trampoline<P, F: Fn(&P, &Asset) + 'static>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Asset) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(asset))
 }
 
-unsafe extern "C" fn asset_removed_trampoline<P>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
+unsafe extern "C" fn asset_removed_trampoline<P, F: Fn(&P, &Asset) + 'static>(this: *mut ffi::GESProject, asset: *mut ffi::GESAsset, f: glib_ffi::gpointer)
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Asset) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(asset))
 }
 
-unsafe extern "C" fn error_loading_asset_trampoline<P>(this: *mut ffi::GESProject, error: *mut glib_ffi::GError, id: *mut libc::c_char, extractable_type: glib_ffi::GType, f: glib_ffi::gpointer)
+unsafe extern "C" fn error_loading_asset_trampoline<P, F: Fn(&P, &Error, &str, glib::types::Type) + 'static>(this: *mut ffi::GESProject, error: *mut glib_ffi::GError, id: *mut libc::c_char, extractable_type: glib_ffi::GType, f: glib_ffi::gpointer)
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Error, &str, glib::types::Type) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(error), &GString::from_glib_borrow(id), from_glib(extractable_type))
 }
 
-unsafe extern "C" fn loaded_trampoline<P>(this: *mut ffi::GESProject, timeline: *mut ffi::GESTimeline, f: glib_ffi::gpointer)
+unsafe extern "C" fn loaded_trampoline<P, F: Fn(&P, &Timeline) + 'static>(this: *mut ffi::GESProject, timeline: *mut ffi::GESTimeline, f: glib_ffi::gpointer)
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Timeline) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(timeline))
 }
 
-unsafe extern "C" fn missing_uri_trampoline<P>(this: *mut ffi::GESProject, error: *mut glib_ffi::GError, wrong_asset: *mut ffi::GESAsset, f: glib_ffi::gpointer) -> *mut libc::c_char
+unsafe extern "C" fn missing_uri_trampoline<P, F: Fn(&P, &Error, &Asset) -> Option<GString> + 'static>(this: *mut ffi::GESProject, error: *mut glib_ffi::GError, wrong_asset: *mut ffi::GESAsset, f: glib_ffi::gpointer) -> *mut libc::c_char
 where P: IsA<Project> {
-    let f: &&(Fn(&P, &Error, &Asset) -> Option<GString> + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Project::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(error), &from_glib_borrow(wrong_asset)).to_glib_full()
 }
diff --git a/gstreamer-editing-services/src/auto/timeline.rs b/gstreamer-editing-services/src/auto/timeline.rs
index a1dfda0e6..d6366e45d 100644
--- a/gstreamer-editing-services/src/auto/timeline.rs
+++ b/gstreamer-editing-services/src/auto/timeline.rs
@@ -292,17 +292,17 @@ impl<O: IsA<Timeline>> TimelineExt for O {
 
     fn connect_commited<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"commited\0".as_ptr() as *const _,
-                transmute(commited_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(commited_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_group_added<F: Fn(&Self, &Group) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Group) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"group-added\0".as_ptr() as *const _,
-                transmute(group_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(group_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
@@ -312,17 +312,17 @@ impl<O: IsA<Timeline>> TimelineExt for O {
 
     fn connect_layer_added<F: Fn(&Self, &Layer) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Layer) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"layer-added\0".as_ptr() as *const _,
-                transmute(layer_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(layer_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_layer_removed<F: Fn(&Self, &Layer) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Layer) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"layer-removed\0".as_ptr() as *const _,
-                transmute(layer_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(layer_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
@@ -332,123 +332,123 @@ impl<O: IsA<Timeline>> TimelineExt for O {
 
     fn connect_snapping_ended<F: Fn(&Self, &TrackElement, &TrackElement, u64) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TrackElement, &TrackElement, u64) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"snapping-ended\0".as_ptr() as *const _,
-                transmute(snapping_ended_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(snapping_ended_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_snapping_started<F: Fn(&Self, &TrackElement, &TrackElement, u64) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TrackElement, &TrackElement, u64) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"snapping-started\0".as_ptr() as *const _,
-                transmute(snapping_started_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(snapping_started_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_track_added<F: Fn(&Self, &Track) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Track) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"track-added\0".as_ptr() as *const _,
-                transmute(track_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(track_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_track_removed<F: Fn(&Self, &Track) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Track) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"track-removed\0".as_ptr() as *const _,
-                transmute(track_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(track_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_auto_transition_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::auto-transition\0".as_ptr() as *const _,
-                transmute(notify_auto_transition_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_auto_transition_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_snapping_distance_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::snapping-distance\0".as_ptr() as *const _,
-                transmute(notify_snapping_distance_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_snapping_distance_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn commited_trampoline<P>(this: *mut ffi::GESTimeline, f: glib_ffi::gpointer)
+unsafe extern "C" fn commited_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimeline, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn group_added_trampoline<P>(this: *mut ffi::GESTimeline, group: *mut ffi::GESGroup, f: glib_ffi::gpointer)
+unsafe extern "C" fn group_added_trampoline<P, F: Fn(&P, &Group) + 'static>(this: *mut ffi::GESTimeline, group: *mut ffi::GESGroup, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &Group) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(group))
 }
 
-unsafe extern "C" fn layer_added_trampoline<P>(this: *mut ffi::GESTimeline, layer: *mut ffi::GESLayer, f: glib_ffi::gpointer)
+unsafe extern "C" fn layer_added_trampoline<P, F: Fn(&P, &Layer) + 'static>(this: *mut ffi::GESTimeline, layer: *mut ffi::GESLayer, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &Layer) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(layer))
 }
 
-unsafe extern "C" fn layer_removed_trampoline<P>(this: *mut ffi::GESTimeline, layer: *mut ffi::GESLayer, f: glib_ffi::gpointer)
+unsafe extern "C" fn layer_removed_trampoline<P, F: Fn(&P, &Layer) + 'static>(this: *mut ffi::GESTimeline, layer: *mut ffi::GESLayer, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &Layer) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(layer))
 }
 
-unsafe extern "C" fn snapping_ended_trampoline<P>(this: *mut ffi::GESTimeline, object: *mut ffi::GESTrackElement, p0: *mut ffi::GESTrackElement, p1: u64, f: glib_ffi::gpointer)
+unsafe extern "C" fn snapping_ended_trampoline<P, F: Fn(&P, &TrackElement, &TrackElement, u64) + 'static>(this: *mut ffi::GESTimeline, object: *mut ffi::GESTrackElement, p0: *mut ffi::GESTrackElement, p1: u64, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &TrackElement, &TrackElement, u64) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object), &from_glib_borrow(p0), p1)
 }
 
-unsafe extern "C" fn snapping_started_trampoline<P>(this: *mut ffi::GESTimeline, object: *mut ffi::GESTrackElement, p0: *mut ffi::GESTrackElement, p1: u64, f: glib_ffi::gpointer)
+unsafe extern "C" fn snapping_started_trampoline<P, F: Fn(&P, &TrackElement, &TrackElement, u64) + 'static>(this: *mut ffi::GESTimeline, object: *mut ffi::GESTrackElement, p0: *mut ffi::GESTrackElement, p1: u64, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &TrackElement, &TrackElement, u64) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object), &from_glib_borrow(p0), p1)
 }
 
-unsafe extern "C" fn track_added_trampoline<P>(this: *mut ffi::GESTimeline, track: *mut ffi::GESTrack, f: glib_ffi::gpointer)
+unsafe extern "C" fn track_added_trampoline<P, F: Fn(&P, &Track) + 'static>(this: *mut ffi::GESTimeline, track: *mut ffi::GESTrack, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &Track) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(track))
 }
 
-unsafe extern "C" fn track_removed_trampoline<P>(this: *mut ffi::GESTimeline, track: *mut ffi::GESTrack, f: glib_ffi::gpointer)
+unsafe extern "C" fn track_removed_trampoline<P, F: Fn(&P, &Track) + 'static>(this: *mut ffi::GESTimeline, track: *mut ffi::GESTrack, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P, &Track) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(track))
 }
 
-unsafe extern "C" fn notify_auto_transition_trampoline<P>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_auto_transition_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_duration_trampoline<P>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_snapping_distance_trampoline<P>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_snapping_distance_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Timeline> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Timeline::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/timeline_element.rs b/gstreamer-editing-services/src/auto/timeline_element.rs
index 96a72f77c..dbb88d9ab 100644
--- a/gstreamer-editing-services/src/auto/timeline_element.rs
+++ b/gstreamer-editing-services/src/auto/timeline_element.rs
@@ -31,7 +31,7 @@ glib_wrapper! {
 pub const NONE_TIMELINE_ELEMENT: Option<&TimelineElement> = None;
 
 pub trait TimelineElementExt: 'static {
-    //fn add_child_property<P: IsA</*Ignored*/glib::ParamSpec>, Q: IsA<glib::Object>>(&self, pspec: &P, child: &Q) -> bool;
+    //fn add_child_property<P: IsA<glib::Object>>(&self, pspec: /*Ignored*/&glib::ParamSpec, child: &P) -> bool;
 
     fn copy(&self, deep: bool) -> Option<TimelineElement>;
 
@@ -39,7 +39,7 @@ pub trait TimelineElementExt: 'static {
 
     //fn get_child_property(&self, property_name: &str, value: /*Ignored*/glib::Value) -> bool;
 
-    //fn get_child_property_by_pspec<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P, value: /*Ignored*/glib::Value);
+    //fn get_child_property_by_pspec(&self, pspec: /*Ignored*/&glib::ParamSpec, value: /*Ignored*/glib::Value);
 
     //fn get_child_property_valist(&self, first_property_name: &str, var_args: /*Unknown conversion*//*Unimplemented*/Unsupported);
 
@@ -69,7 +69,7 @@ pub trait TimelineElementExt: 'static {
 
     fn paste(&self, paste_position: gst::ClockTime) -> Option<TimelineElement>;
 
-    //fn remove_child_property<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P) -> bool;
+    //fn remove_child_property(&self, pspec: /*Ignored*/&glib::ParamSpec) -> bool;
 
     fn ripple(&self, start: gst::ClockTime) -> bool;
 
@@ -83,7 +83,7 @@ pub trait TimelineElementExt: 'static {
 
     //fn set_child_property(&self, property_name: &str, value: /*Ignored*/&glib::Value) -> bool;
 
-    //fn set_child_property_by_pspec<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P, value: /*Ignored*/&glib::Value);
+    //fn set_child_property_by_pspec(&self, pspec: /*Ignored*/&glib::ParamSpec, value: /*Ignored*/&glib::Value);
 
     //fn set_child_property_valist(&self, first_property_name: &str, var_args: /*Unknown conversion*//*Unimplemented*/Unsupported);
 
@@ -135,7 +135,7 @@ pub trait TimelineElementExt: 'static {
 }
 
 impl<O: IsA<TimelineElement>> TimelineElementExt for O {
-    //fn add_child_property<P: IsA</*Ignored*/glib::ParamSpec>, Q: IsA<glib::Object>>(&self, pspec: &P, child: &Q) -> bool {
+    //fn add_child_property<P: IsA<glib::Object>>(&self, pspec: /*Ignored*/&glib::ParamSpec, child: &P) -> bool {
     //    unsafe { TODO: call ffi::ges_timeline_element_add_child_property() }
     //}
 
@@ -153,7 +153,7 @@ impl<O: IsA<TimelineElement>> TimelineElementExt for O {
     //    unsafe { TODO: call ffi::ges_timeline_element_get_child_property() }
     //}
 
-    //fn get_child_property_by_pspec<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P, value: /*Ignored*/glib::Value) {
+    //fn get_child_property_by_pspec(&self, pspec: /*Ignored*/&glib::ParamSpec, value: /*Ignored*/glib::Value) {
     //    unsafe { TODO: call ffi::ges_timeline_element_get_child_property_by_pspec() }
     //}
 
@@ -235,7 +235,7 @@ impl<O: IsA<TimelineElement>> TimelineElementExt for O {
         }
     }
 
-    //fn remove_child_property<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P) -> bool {
+    //fn remove_child_property(&self, pspec: /*Ignored*/&glib::ParamSpec) -> bool {
     //    unsafe { TODO: call ffi::ges_timeline_element_remove_child_property() }
     //}
 
@@ -271,7 +271,7 @@ impl<O: IsA<TimelineElement>> TimelineElementExt for O {
     //    unsafe { TODO: call ffi::ges_timeline_element_set_child_property() }
     //}
 
-    //fn set_child_property_by_pspec<P: IsA</*Ignored*/glib::ParamSpec>>(&self, pspec: &P, value: /*Ignored*/&glib::Value) {
+    //fn set_child_property_by_pspec(&self, pspec: /*Ignored*/&glib::ParamSpec, value: /*Ignored*/&glib::Value) {
     //    unsafe { TODO: call ffi::ges_timeline_element_set_child_property_by_pspec() }
     //}
 
@@ -368,127 +368,127 @@ impl<O: IsA<TimelineElement>> TimelineElementExt for O {
 
     fn connect_property_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_in_point_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::in-point\0".as_ptr() as *const _,
-                transmute(notify_in_point_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_in_point_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_max_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-duration\0".as_ptr() as *const _,
-                transmute(notify_max_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_name_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::name\0".as_ptr() as *const _,
-                transmute(notify_name_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_name_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_parent_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::parent\0".as_ptr() as *const _,
-                transmute(notify_parent_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_parent_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_priority_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::priority\0".as_ptr() as *const _,
-                transmute(notify_priority_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_priority_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_serialize_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::serialize\0".as_ptr() as *const _,
-                transmute(notify_serialize_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_serialize_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_start_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::start\0".as_ptr() as *const _,
-                transmute(notify_start_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_start_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_timeline_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::timeline\0".as_ptr() as *const _,
-                transmute(notify_timeline_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_timeline_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_duration_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_in_point_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_in_point_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_max_duration_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_name_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_name_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_parent_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_parent_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_priority_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_priority_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_serialize_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_serialize_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_start_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_start_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_timeline_trampoline<P>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_timeline_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTimelineElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TimelineElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TimelineElement::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/track.rs b/gstreamer-editing-services/src/auto/track.rs
index 01894523b..5de333269 100644
--- a/gstreamer-editing-services/src/auto/track.rs
+++ b/gstreamer-editing-services/src/auto/track.rs
@@ -54,7 +54,7 @@ pub trait GESTrackExt: 'static {
 
     fn remove_element<P: IsA<TrackElement>>(&self, object: &P) -> Result<(), glib::error::BoolError>;
 
-    //fn set_create_element_for_gap_func(&self, func: /*Unknown conversion*//*Unimplemented*/CreateElementForGapFunc);
+    //fn set_create_element_for_gap_func<P: Fn(&Track) -> gst::Element + 'static>(&self, func: P);
 
     fn set_mixing(&self, mixing: bool);
 
@@ -126,7 +126,7 @@ impl<O: IsA<Track>> GESTrackExt for O {
         }
     }
 
-    //fn set_create_element_for_gap_func(&self, func: /*Unknown conversion*//*Unimplemented*/CreateElementForGapFunc) {
+    //fn set_create_element_for_gap_func<P: Fn(&Track) -> gst::Element + 'static>(&self, func: P) {
     //    unsafe { TODO: call ffi::ges_track_set_create_element_for_gap_func() }
     //}
 
@@ -180,85 +180,85 @@ impl<O: IsA<Track>> GESTrackExt for O {
 
     fn connect_commited<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"commited\0".as_ptr() as *const _,
-                transmute(commited_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(commited_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_track_element_added<F: Fn(&Self, &TrackElement) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TrackElement) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"track-element-added\0".as_ptr() as *const _,
-                transmute(track_element_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(track_element_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_track_element_removed<F: Fn(&Self, &TrackElement) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &TrackElement) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"track-element-removed\0".as_ptr() as *const _,
-                transmute(track_element_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(track_element_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_mixing_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mixing\0".as_ptr() as *const _,
-                transmute(notify_mixing_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mixing_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_restriction_caps_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::restriction-caps\0".as_ptr() as *const _,
-                transmute(notify_restriction_caps_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_restriction_caps_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn commited_trampoline<P>(this: *mut ffi::GESTrack, f: glib_ffi::gpointer)
+unsafe extern "C" fn commited_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrack, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn track_element_added_trampoline<P>(this: *mut ffi::GESTrack, effect: *mut ffi::GESTrackElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn track_element_added_trampoline<P, F: Fn(&P, &TrackElement) + 'static>(this: *mut ffi::GESTrack, effect: *mut ffi::GESTrackElement, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P, &TrackElement) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(effect))
 }
 
-unsafe extern "C" fn track_element_removed_trampoline<P>(this: *mut ffi::GESTrack, effect: *mut ffi::GESTrackElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn track_element_removed_trampoline<P, F: Fn(&P, &TrackElement) + 'static>(this: *mut ffi::GESTrack, effect: *mut ffi::GESTrackElement, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P, &TrackElement) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(effect))
 }
 
-unsafe extern "C" fn notify_duration_trampoline<P>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_mixing_trampoline<P>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mixing_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_restriction_caps_trampoline<P>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_restriction_caps_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrack, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Track> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Track::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/track_element.rs b/gstreamer-editing-services/src/auto/track_element.rs
index 14ca637e7..2cb9356b3 100644
--- a/gstreamer-editing-services/src/auto/track_element.rs
+++ b/gstreamer-editing-services/src/auto/track_element.rs
@@ -61,7 +61,7 @@ pub trait TrackElementExt: 'static {
 
     fn set_active(&self, active: bool) -> bool;
 
-    //fn set_control_source<P: IsA</*Ignored*/gst::ControlSource>>(&self, source: &P, property_name: &str, binding_type: &str) -> bool;
+    //fn set_control_source(&self, source: /*Ignored*/&gst::ControlSource, property_name: &str, binding_type: &str) -> bool;
 
     fn set_track_type(&self, type_: TrackType);
 
@@ -151,7 +151,7 @@ impl<O: IsA<TrackElement>> TrackElementExt for O {
         }
     }
 
-    //fn set_control_source<P: IsA</*Ignored*/gst::ControlSource>>(&self, source: &P, property_name: &str, binding_type: &str) -> bool {
+    //fn set_control_source(&self, source: /*Ignored*/&gst::ControlSource, property_name: &str, binding_type: &str) -> bool {
     //    unsafe { TODO: call ffi::ges_track_element_set_control_source() }
     //}
 
@@ -179,43 +179,43 @@ impl<O: IsA<TrackElement>> TrackElementExt for O {
 
     fn connect_property_active_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::active\0".as_ptr() as *const _,
-                transmute(notify_active_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_active_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_track_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::track\0".as_ptr() as *const _,
-                transmute(notify_track_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_track_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_track_type_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::track-type\0".as_ptr() as *const _,
-                transmute(notify_track_type_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_track_type_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_active_trampoline<P>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_active_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TrackElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TrackElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_track_trampoline<P>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_track_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TrackElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TrackElement::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_track_type_trampoline<P>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_track_type_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESTrackElement, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<TrackElement> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&TrackElement::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/uri_clip.rs b/gstreamer-editing-services/src/auto/uri_clip.rs
index 2cec8fd84..020508e51 100644
--- a/gstreamer-editing-services/src/auto/uri_clip.rs
+++ b/gstreamer-editing-services/src/auto/uri_clip.rs
@@ -29,7 +29,7 @@ glib_wrapper! {
 }
 
 impl UriClip {
-    pub fn new(uri: &str) -> UriClip {
+    pub fn new(uri: &str) -> Option<UriClip> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_none(ffi::ges_uri_clip_new(uri.to_glib_none().0))
@@ -110,43 +110,43 @@ impl<O: IsA<UriClip>> UriClipExt for O {
 
     fn connect_property_is_image_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::is-image\0".as_ptr() as *const _,
-                transmute(notify_is_image_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_is_image_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_mute_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mute\0".as_ptr() as *const _,
-                transmute(notify_mute_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mute_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_supported_formats_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::supported-formats\0".as_ptr() as *const _,
-                transmute(notify_supported_formats_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_supported_formats_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_is_image_trampoline<P>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_is_image_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UriClip> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&UriClip::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_mute_trampoline<P>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mute_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UriClip> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&UriClip::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_supported_formats_trampoline<P>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_supported_formats_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESUriClip, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UriClip> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&UriClip::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/uri_clip_asset.rs b/gstreamer-editing-services/src/auto/uri_clip_asset.rs
index 247d1c18d..4ff4d3389 100644
--- a/gstreamer-editing-services/src/auto/uri_clip_asset.rs
+++ b/gstreamer-editing-services/src/auto/uri_clip_asset.rs
@@ -29,7 +29,7 @@ glib_wrapper! {
 }
 
 impl UriClipAsset {
-    //pub fn new<'a, P: IsA<gio::Cancellable> + 'a, Q: Into<Option<&'a P>>, R: /*Unimplemented*/gio::AsyncReadyCallback>(uri: &str, cancellable: Q, callback: R) {
+    //pub fn new<'a, P: IsA<gio::Cancellable> + 'a, Q: Into<Option<&'a P>>, R: FnOnce(Result<(), Error>) + 'static>(uri: &str, cancellable: Q, callback: R) {
     //    unsafe { TODO: call ffi::ges_uri_clip_asset_new() }
     //}
 
@@ -92,15 +92,15 @@ impl<O: IsA<UriClipAsset>> UriClipAssetExt for O {
 
     fn connect_property_duration_notify<F: Fn(&Self) + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_duration_trampoline<P>(this: *mut ffi::GESUriClipAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_duration_trampoline<P, F: Fn(&P) + 'static>(this: *mut ffi::GESUriClipAsset, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<UriClipAsset> {
-    let f: &&(Fn(&P) + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&UriClipAsset::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-editing-services/src/auto/versions.txt b/gstreamer-editing-services/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-editing-services/src/auto/versions.txt
+++ b/gstreamer-editing-services/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-gl/src/auto/gl_base_filter.rs b/gstreamer-gl/src/auto/gl_base_filter.rs
index 2d6aa8771..0346e5a71 100644
--- a/gstreamer-gl/src/auto/gl_base_filter.rs
+++ b/gstreamer-gl/src/auto/gl_base_filter.rs
@@ -47,15 +47,15 @@ impl<O: IsA<GLBaseFilter>> GLBaseFilterExt for O {
 
     fn connect_property_context_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::context\0".as_ptr() as *const _,
-                transmute(notify_context_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_context_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_context_trampoline<P>(this: *mut ffi::GstGLBaseFilter, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_context_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstGLBaseFilter, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<GLBaseFilter> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&GLBaseFilter::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-gl/src/auto/gl_display.rs b/gstreamer-gl/src/auto/gl_display.rs
index b98e236da..9da8c496c 100644
--- a/gstreamer-gl/src/auto/gl_display.rs
+++ b/gstreamer-gl/src/auto/gl_display.rs
@@ -122,15 +122,15 @@ impl<O: IsA<GLDisplay>> GLDisplayExt for O {
 
     fn connect_create_context<F: Fn(&Self, &GLContext) -> GLContext + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &GLContext) -> GLContext + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"create-context\0".as_ptr() as *const _,
-                transmute(create_context_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(create_context_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn create_context_trampoline<P>(this: *mut ffi::GstGLDisplay, context: *mut ffi::GstGLContext, f: glib_ffi::gpointer) -> *mut ffi::GstGLContext
+unsafe extern "C" fn create_context_trampoline<P, F: Fn(&P, &GLContext) -> GLContext + Send + Sync + 'static>(this: *mut ffi::GstGLDisplay, context: *mut ffi::GstGLContext, f: glib_ffi::gpointer) -> *mut ffi::GstGLContext
 where P: IsA<GLDisplay> {
-    let f: &&(Fn(&P, &GLContext) -> GLContext + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&GLDisplay::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(context)).to_glib_full()
 }
diff --git a/gstreamer-gl/src/auto/gl_display_egl.rs b/gstreamer-gl/src/auto/gl_display_egl.rs
index 0a97f0880..18dfac41c 100644
--- a/gstreamer-gl/src/auto/gl_display_egl.rs
+++ b/gstreamer-gl/src/auto/gl_display_egl.rs
@@ -23,7 +23,7 @@ impl GLDisplayEGL {
         }
     }
 
-    //pub fn new_with_egl_display<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(display: P) -> GLDisplayEGL {
+    //pub fn new_with_egl_display(display: /*Unimplemented*/Option<Fundamental: Pointer>) -> GLDisplayEGL {
     //    unsafe { TODO: call ffi::gst_gl_display_egl_new_with_egl_display() }
     //}
 
diff --git a/gstreamer-gl/src/auto/gl_framebuffer.rs b/gstreamer-gl/src/auto/gl_framebuffer.rs
index bad058750..5c5c7e219 100644
--- a/gstreamer-gl/src/auto/gl_framebuffer.rs
+++ b/gstreamer-gl/src/auto/gl_framebuffer.rs
@@ -43,7 +43,7 @@ pub trait GLFramebufferExt: 'static {
 
     fn bind(&self);
 
-    //fn draw_to_texture<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, mem: /*Ignored*/&mut GLMemory, func: /*Unknown conversion*//*Unimplemented*/GLFramebufferFunc, user_data: P) -> bool;
+    //fn draw_to_texture(&self, mem: /*Ignored*/&mut GLMemory, func: /*Unimplemented*/Fn(/*Unimplemented*/Fundamental: Pointer) -> bool, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> bool;
 
     fn get_effective_dimensions(&self) -> (u32, u32);
 
@@ -61,7 +61,7 @@ impl<O: IsA<GLFramebuffer>> GLFramebufferExt for O {
         }
     }
 
-    //fn draw_to_texture<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, mem: /*Ignored*/&mut GLMemory, func: /*Unknown conversion*//*Unimplemented*/GLFramebufferFunc, user_data: P) -> bool {
+    //fn draw_to_texture(&self, mem: /*Ignored*/&mut GLMemory, func: /*Unimplemented*/Fn(/*Unimplemented*/Fundamental: Pointer) -> bool, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> bool {
     //    unsafe { TODO: call ffi::gst_gl_framebuffer_draw_to_texture() }
     //}
 
diff --git a/gstreamer-gl/src/auto/gl_shader.rs b/gstreamer-gl/src/auto/gl_shader.rs
index 2e9a9efe2..4b8a5bd51 100644
--- a/gstreamer-gl/src/auto/gl_shader.rs
+++ b/gstreamer-gl/src/auto/gl_shader.rs
@@ -255,9 +255,9 @@ impl GLShader {
 
     pub fn connect_property_linked_notify<F: Fn(&GLShader) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLShader) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::linked\0".as_ptr() as *const _,
-                transmute(notify_linked_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_linked_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -265,7 +265,7 @@ impl GLShader {
 unsafe impl Send for GLShader {}
 unsafe impl Sync for GLShader {}
 
-unsafe extern "C" fn notify_linked_trampoline(this: *mut ffi::GstGLShader, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLShader) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_linked_trampoline<F: Fn(&GLShader) + Send + Sync + 'static>(this: *mut ffi::GstGLShader, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-gl/src/auto/gl_view_convert.rs b/gstreamer-gl/src/auto/gl_view_convert.rs
index 60cb5a1f1..c96124ba7 100644
--- a/gstreamer-gl/src/auto/gl_view_convert.rs
+++ b/gstreamer-gl/src/auto/gl_view_convert.rs
@@ -137,41 +137,41 @@ impl GLViewConvert {
 
     pub fn connect_property_downmix_mode_notify<F: Fn(&GLViewConvert) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLViewConvert) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::downmix-mode\0".as_ptr() as *const _,
-                transmute(notify_downmix_mode_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_downmix_mode_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_input_flags_override_notify<F: Fn(&GLViewConvert) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLViewConvert) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::input-flags-override\0".as_ptr() as *const _,
-                transmute(notify_input_flags_override_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_input_flags_override_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_input_mode_override_notify<F: Fn(&GLViewConvert) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLViewConvert) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::input-mode-override\0".as_ptr() as *const _,
-                transmute(notify_input_mode_override_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_input_mode_override_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_output_flags_override_notify<F: Fn(&GLViewConvert) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLViewConvert) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::output-flags-override\0".as_ptr() as *const _,
-                transmute(notify_output_flags_override_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_output_flags_override_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_output_mode_override_notify<F: Fn(&GLViewConvert) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&GLViewConvert) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::output-mode-override\0".as_ptr() as *const _,
-                transmute(notify_output_mode_override_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_output_mode_override_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -185,27 +185,27 @@ impl Default for GLViewConvert {
 unsafe impl Send for GLViewConvert {}
 unsafe impl Sync for GLViewConvert {}
 
-unsafe extern "C" fn notify_downmix_mode_trampoline(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLViewConvert) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_downmix_mode_trampoline<F: Fn(&GLViewConvert) + Send + Sync + 'static>(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_input_flags_override_trampoline(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLViewConvert) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_input_flags_override_trampoline<F: Fn(&GLViewConvert) + Send + Sync + 'static>(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_input_mode_override_trampoline(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLViewConvert) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_input_mode_override_trampoline<F: Fn(&GLViewConvert) + Send + Sync + 'static>(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_output_flags_override_trampoline(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLViewConvert) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_output_flags_override_trampoline<F: Fn(&GLViewConvert) + Send + Sync + 'static>(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_output_mode_override_trampoline(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&GLViewConvert) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_output_mode_override_trampoline<F: Fn(&GLViewConvert) + Send + Sync + 'static>(this: *mut ffi::GstGLViewConvert, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-gl/src/auto/gl_window.rs b/gstreamer-gl/src/auto/gl_window.rs
index 1eda38a4f..182174e81 100644
--- a/gstreamer-gl/src/auto/gl_window.rs
+++ b/gstreamer-gl/src/auto/gl_window.rs
@@ -156,29 +156,29 @@ impl<O: IsA<GLWindow>> GLWindowExt for O {
 
     fn connect_key_event<F: Fn(&Self, &str, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &str, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"key-event\0".as_ptr() as *const _,
-                transmute(key_event_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(key_event_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_mouse_event<F: Fn(&Self, &str, i32, f64, f64) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &str, i32, f64, f64) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"mouse-event\0".as_ptr() as *const _,
-                transmute(mouse_event_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(mouse_event_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn key_event_trampoline<P>(this: *mut ffi::GstGLWindow, id: *mut libc::c_char, key: *mut libc::c_char, f: glib_ffi::gpointer)
+unsafe extern "C" fn key_event_trampoline<P, F: Fn(&P, &str, &str) + Send + Sync + 'static>(this: *mut ffi::GstGLWindow, id: *mut libc::c_char, key: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<GLWindow> {
-    let f: &&(Fn(&P, &str, &str) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&GLWindow::from_glib_borrow(this).unsafe_cast(), &GString::from_glib_borrow(id), &GString::from_glib_borrow(key))
 }
 
-unsafe extern "C" fn mouse_event_trampoline<P>(this: *mut ffi::GstGLWindow, id: *mut libc::c_char, button: libc::c_int, x: libc::c_double, y: libc::c_double, f: glib_ffi::gpointer)
+unsafe extern "C" fn mouse_event_trampoline<P, F: Fn(&P, &str, i32, f64, f64) + Send + Sync + 'static>(this: *mut ffi::GstGLWindow, id: *mut libc::c_char, button: libc::c_int, x: libc::c_double, y: libc::c_double, f: glib_ffi::gpointer)
 where P: IsA<GLWindow> {
-    let f: &&(Fn(&P, &str, i32, f64, f64) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&GLWindow::from_glib_borrow(this).unsafe_cast(), &GString::from_glib_borrow(id), button, x, y)
 }
diff --git a/gstreamer-gl/src/auto/versions.txt b/gstreamer-gl/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-gl/src/auto/versions.txt
+++ b/gstreamer-gl/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-net/src/auto/net_client_clock.rs b/gstreamer-net/src/auto/net_client_clock.rs
index bf0534185..e3db228cb 100644
--- a/gstreamer-net/src/auto/net_client_clock.rs
+++ b/gstreamer-net/src/auto/net_client_clock.rs
@@ -130,57 +130,57 @@ impl NetClientClock {
 
     pub fn connect_property_address_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::address\0".as_ptr() as *const _,
-                transmute(notify_address_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_address_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_bus_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::bus\0".as_ptr() as *const _,
-                transmute(notify_bus_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_bus_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_internal_clock_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::internal-clock\0".as_ptr() as *const _,
-                transmute(notify_internal_clock_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_internal_clock_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_minimum_update_interval_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::minimum-update-interval\0".as_ptr() as *const _,
-                transmute(notify_minimum_update_interval_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_minimum_update_interval_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_port_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::port\0".as_ptr() as *const _,
-                transmute(notify_port_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_port_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_qos_dscp_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::qos-dscp\0".as_ptr() as *const _,
-                transmute(notify_qos_dscp_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_qos_dscp_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_round_trip_limit_notify<F: Fn(&NetClientClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetClientClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::round-trip-limit\0".as_ptr() as *const _,
-                transmute(notify_round_trip_limit_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_round_trip_limit_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -188,37 +188,37 @@ impl NetClientClock {
 unsafe impl Send for NetClientClock {}
 unsafe impl Sync for NetClientClock {}
 
-unsafe extern "C" fn notify_address_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_address_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_bus_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_bus_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_internal_clock_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_internal_clock_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_minimum_update_interval_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_minimum_update_interval_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_port_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_port_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_qos_dscp_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_qos_dscp_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_round_trip_limit_trampoline(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetClientClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_round_trip_limit_trampoline<F: Fn(&NetClientClock) + Send + Sync + 'static>(this: *mut ffi::GstNetClientClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-net/src/auto/net_time_provider.rs b/gstreamer-net/src/auto/net_time_provider.rs
index 9b5fffddd..0f53d2f77 100644
--- a/gstreamer-net/src/auto/net_time_provider.rs
+++ b/gstreamer-net/src/auto/net_time_provider.rs
@@ -79,17 +79,17 @@ impl NetTimeProvider {
 
     pub fn connect_property_active_notify<F: Fn(&NetTimeProvider) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetTimeProvider) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::active\0".as_ptr() as *const _,
-                transmute(notify_active_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_active_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_qos_dscp_notify<F: Fn(&NetTimeProvider) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&NetTimeProvider) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::qos-dscp\0".as_ptr() as *const _,
-                transmute(notify_qos_dscp_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_qos_dscp_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -97,12 +97,12 @@ impl NetTimeProvider {
 unsafe impl Send for NetTimeProvider {}
 unsafe impl Sync for NetTimeProvider {}
 
-unsafe extern "C" fn notify_active_trampoline(this: *mut ffi::GstNetTimeProvider, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetTimeProvider) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_active_trampoline<F: Fn(&NetTimeProvider) + Send + Sync + 'static>(this: *mut ffi::GstNetTimeProvider, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_qos_dscp_trampoline(this: *mut ffi::GstNetTimeProvider, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&NetTimeProvider) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_qos_dscp_trampoline<F: Fn(&NetTimeProvider) + Send + Sync + 'static>(this: *mut ffi::GstNetTimeProvider, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-net/src/auto/ptp_clock.rs b/gstreamer-net/src/auto/ptp_clock.rs
index 84ca6ab39..ae220f732 100644
--- a/gstreamer-net/src/auto/ptp_clock.rs
+++ b/gstreamer-net/src/auto/ptp_clock.rs
@@ -58,25 +58,25 @@ impl PtpClock {
 
     pub fn connect_property_grandmaster_clock_id_notify<F: Fn(&PtpClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PtpClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::grandmaster-clock-id\0".as_ptr() as *const _,
-                transmute(notify_grandmaster_clock_id_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_grandmaster_clock_id_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_internal_clock_notify<F: Fn(&PtpClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PtpClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::internal-clock\0".as_ptr() as *const _,
-                transmute(notify_internal_clock_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_internal_clock_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_master_clock_id_notify<F: Fn(&PtpClock) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PtpClock) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::master-clock-id\0".as_ptr() as *const _,
-                transmute(notify_master_clock_id_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_master_clock_id_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -84,17 +84,17 @@ impl PtpClock {
 unsafe impl Send for PtpClock {}
 unsafe impl Sync for PtpClock {}
 
-unsafe extern "C" fn notify_grandmaster_clock_id_trampoline(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PtpClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_grandmaster_clock_id_trampoline<F: Fn(&PtpClock) + Send + Sync + 'static>(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_internal_clock_trampoline(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PtpClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_internal_clock_trampoline<F: Fn(&PtpClock) + Send + Sync + 'static>(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_master_clock_id_trampoline(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PtpClock) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_master_clock_id_trampoline<F: Fn(&PtpClock) + Send + Sync + 'static>(this: *mut ffi::GstPtpClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-net/src/auto/versions.txt b/gstreamer-net/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-net/src/auto/versions.txt
+++ b/gstreamer-net/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-pbutils/src/auto/discoverer.rs b/gstreamer-pbutils/src/auto/discoverer.rs
index fcb5e02bc..b4939c3a0 100644
--- a/gstreamer-pbutils/src/auto/discoverer.rs
+++ b/gstreamer-pbutils/src/auto/discoverer.rs
@@ -63,33 +63,33 @@ impl Discoverer {
 
     pub fn connect_discovered<F: Fn(&Discoverer, &DiscovererInfo, &Option<Error>) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Discoverer, &DiscovererInfo, &Option<Error>) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"discovered\0".as_ptr() as *const _,
-                transmute(discovered_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(discovered_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_finished<F: Fn(&Discoverer) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Discoverer) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"finished\0".as_ptr() as *const _,
-                transmute(finished_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(finished_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_source_setup<F: Fn(&Discoverer, &gst::Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Discoverer, &gst::Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"source-setup\0".as_ptr() as *const _,
-                transmute(source_setup_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(source_setup_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_starting<F: Fn(&Discoverer) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Discoverer) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"starting\0".as_ptr() as *const _,
-                transmute(starting_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(starting_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -97,22 +97,22 @@ impl Discoverer {
 unsafe impl Send for Discoverer {}
 unsafe impl Sync for Discoverer {}
 
-unsafe extern "C" fn discovered_trampoline(this: *mut ffi::GstDiscoverer, info: *mut ffi::GstDiscovererInfo, error: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Discoverer, &DiscovererInfo, &Option<Error>) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn discovered_trampoline<F: Fn(&Discoverer, &DiscovererInfo, &Option<Error>) + Send + Sync + 'static>(this: *mut ffi::GstDiscoverer, info: *mut ffi::GstDiscovererInfo, error: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(info), &from_glib_borrow(error))
 }
 
-unsafe extern "C" fn finished_trampoline(this: *mut ffi::GstDiscoverer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Discoverer) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn finished_trampoline<F: Fn(&Discoverer) + Send + Sync + 'static>(this: *mut ffi::GstDiscoverer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn source_setup_trampoline(this: *mut ffi::GstDiscoverer, source: *mut gst_ffi::GstElement, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Discoverer, &gst::Element) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn source_setup_trampoline<F: Fn(&Discoverer, &gst::Element) + Send + Sync + 'static>(this: *mut ffi::GstDiscoverer, source: *mut gst_ffi::GstElement, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(source))
 }
 
-unsafe extern "C" fn starting_trampoline(this: *mut ffi::GstDiscoverer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Discoverer) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn starting_trampoline<F: Fn(&Discoverer) + Send + Sync + 'static>(this: *mut ffi::GstDiscoverer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-pbutils/src/auto/versions.txt b/gstreamer-pbutils/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-pbutils/src/auto/versions.txt
+++ b/gstreamer-pbutils/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-player/src/auto/player.rs b/gstreamer-player/src/auto/player.rs
index 2ab4d900b..c39225e71 100644
--- a/gstreamer-player/src/auto/player.rs
+++ b/gstreamer-player/src/auto/player.rs
@@ -352,201 +352,201 @@ impl Player {
 
     pub fn connect_buffering<F: Fn(&Player, i32) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, i32) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"buffering\0".as_ptr() as *const _,
-                transmute(buffering_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(buffering_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_end_of_stream<F: Fn(&Player) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"end-of-stream\0".as_ptr() as *const _,
-                transmute(end_of_stream_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(end_of_stream_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_error<F: Fn(&Player, &Error) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, &Error) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"error\0".as_ptr() as *const _,
-                transmute(error_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(error_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_media_info_updated<F: Fn(&Player, &PlayerMediaInfo) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, &PlayerMediaInfo) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"media-info-updated\0".as_ptr() as *const _,
-                transmute(media_info_updated_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(media_info_updated_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_mute_changed<F: Fn(&Player) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"mute-changed\0".as_ptr() as *const _,
-                transmute(mute_changed_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(mute_changed_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_state_changed<F: Fn(&Player, PlayerState) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, PlayerState) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"state-changed\0".as_ptr() as *const _,
-                transmute(state_changed_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(state_changed_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_uri_loaded<F: Fn(&Player, &str) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, &str) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"uri-loaded\0".as_ptr() as *const _,
-                transmute(uri_loaded_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(uri_loaded_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_video_dimensions_changed<F: Fn(&Player, i32, i32) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, i32, i32) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"video-dimensions-changed\0".as_ptr() as *const _,
-                transmute(video_dimensions_changed_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(video_dimensions_changed_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_volume_changed<F: Fn(&Player) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"volume-changed\0".as_ptr() as *const _,
-                transmute(volume_changed_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(volume_changed_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_warning<F: Fn(&Player, &Error) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player, &Error) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"warning\0".as_ptr() as *const _,
-                transmute(warning_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(warning_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_audio_video_offset_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::audio-video-offset\0".as_ptr() as *const _,
-                transmute(notify_audio_video_offset_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_audio_video_offset_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_current_audio_track_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::current-audio-track\0".as_ptr() as *const _,
-                transmute(notify_current_audio_track_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_current_audio_track_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_current_subtitle_track_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::current-subtitle-track\0".as_ptr() as *const _,
-                transmute(notify_current_subtitle_track_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_current_subtitle_track_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_current_video_track_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::current-video-track\0".as_ptr() as *const _,
-                transmute(notify_current_video_track_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_current_video_track_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_duration_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::duration\0".as_ptr() as *const _,
-                transmute(notify_duration_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_duration_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_media_info_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::media-info\0".as_ptr() as *const _,
-                transmute(notify_media_info_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_media_info_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_mute_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mute\0".as_ptr() as *const _,
-                transmute(notify_mute_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mute_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_pipeline_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::pipeline\0".as_ptr() as *const _,
-                transmute(notify_pipeline_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_pipeline_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_position_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::position\0".as_ptr() as *const _,
-                transmute(notify_position_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_position_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_rate_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::rate\0".as_ptr() as *const _,
-                transmute(notify_rate_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_rate_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_suburi_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::suburi\0".as_ptr() as *const _,
-                transmute(notify_suburi_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_suburi_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_uri_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::uri\0".as_ptr() as *const _,
-                transmute(notify_uri_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_uri_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_video_multiview_flags_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::video-multiview-flags\0".as_ptr() as *const _,
-                transmute(notify_video_multiview_flags_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_video_multiview_flags_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_video_multiview_mode_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::video-multiview-mode\0".as_ptr() as *const _,
-                transmute(notify_video_multiview_mode_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_video_multiview_mode_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_volume_notify<F: Fn(&Player) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Player) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::volume\0".as_ptr() as *const _,
-                transmute(notify_volume_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_volume_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -554,127 +554,127 @@ impl Player {
 unsafe impl Send for Player {}
 unsafe impl Sync for Player {}
 
-unsafe extern "C" fn buffering_trampoline(this: *mut ffi::GstPlayer, object: libc::c_int, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, i32) + Send + 'static) = transmute(f);
+unsafe extern "C" fn buffering_trampoline<F: Fn(&Player, i32) + Send + 'static>(this: *mut ffi::GstPlayer, object: libc::c_int, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), object)
 }
 
-unsafe extern "C" fn end_of_stream_trampoline(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + 'static) = transmute(f);
+unsafe extern "C" fn end_of_stream_trampoline<F: Fn(&Player) + Send + 'static>(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn error_trampoline(this: *mut ffi::GstPlayer, object: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, &Error) + Send + 'static) = transmute(f);
+unsafe extern "C" fn error_trampoline<F: Fn(&Player, &Error) + Send + 'static>(this: *mut ffi::GstPlayer, object: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn media_info_updated_trampoline(this: *mut ffi::GstPlayer, object: *mut ffi::GstPlayerMediaInfo, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, &PlayerMediaInfo) + Send + 'static) = transmute(f);
+unsafe extern "C" fn media_info_updated_trampoline<F: Fn(&Player, &PlayerMediaInfo) + Send + 'static>(this: *mut ffi::GstPlayer, object: *mut ffi::GstPlayerMediaInfo, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn mute_changed_trampoline(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + 'static) = transmute(f);
+unsafe extern "C" fn mute_changed_trampoline<F: Fn(&Player) + Send + 'static>(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn state_changed_trampoline(this: *mut ffi::GstPlayer, object: ffi::GstPlayerState, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, PlayerState) + Send + 'static) = transmute(f);
+unsafe extern "C" fn state_changed_trampoline<F: Fn(&Player, PlayerState) + Send + 'static>(this: *mut ffi::GstPlayer, object: ffi::GstPlayerState, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), from_glib(object))
 }
 
-unsafe extern "C" fn uri_loaded_trampoline(this: *mut ffi::GstPlayer, object: *mut libc::c_char, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, &str) + Send + 'static) = transmute(f);
+unsafe extern "C" fn uri_loaded_trampoline<F: Fn(&Player, &str) + Send + 'static>(this: *mut ffi::GstPlayer, object: *mut libc::c_char, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &GString::from_glib_borrow(object))
 }
 
-unsafe extern "C" fn video_dimensions_changed_trampoline(this: *mut ffi::GstPlayer, object: libc::c_int, p0: libc::c_int, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, i32, i32) + Send + 'static) = transmute(f);
+unsafe extern "C" fn video_dimensions_changed_trampoline<F: Fn(&Player, i32, i32) + Send + 'static>(this: *mut ffi::GstPlayer, object: libc::c_int, p0: libc::c_int, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), object, p0)
 }
 
-unsafe extern "C" fn volume_changed_trampoline(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + 'static) = transmute(f);
+unsafe extern "C" fn volume_changed_trampoline<F: Fn(&Player) + Send + 'static>(this: *mut ffi::GstPlayer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn warning_trampoline(this: *mut ffi::GstPlayer, object: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player, &Error) + Send + 'static) = transmute(f);
+unsafe extern "C" fn warning_trampoline<F: Fn(&Player, &Error) + Send + 'static>(this: *mut ffi::GstPlayer, object: *mut glib_ffi::GError, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn notify_audio_video_offset_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_audio_video_offset_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_current_audio_track_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_current_audio_track_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_current_subtitle_track_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_current_subtitle_track_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_current_video_track_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_current_video_track_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_duration_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_duration_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_media_info_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_media_info_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_mute_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_mute_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_pipeline_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_pipeline_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_position_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_position_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_rate_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_rate_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_suburi_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_suburi_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_uri_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_uri_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_video_multiview_flags_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_video_multiview_flags_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_video_multiview_mode_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_video_multiview_mode_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_volume_trampoline(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Player) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_volume_trampoline<F: Fn(&Player) + Send + Sync + 'static>(this: *mut ffi::GstPlayer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-player/src/auto/player_video_overlay_video_renderer.rs b/gstreamer-player/src/auto/player_video_overlay_video_renderer.rs
index 4846f5e87..faafa7738 100644
--- a/gstreamer-player/src/auto/player_video_overlay_video_renderer.rs
+++ b/gstreamer-player/src/auto/player_video_overlay_video_renderer.rs
@@ -55,7 +55,7 @@ impl PlayerVideoOverlayVideoRenderer {
         }
     }
 
-    //pub fn set_window_handle<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, window_handle: P) {
+    //pub fn set_window_handle(&self, window_handle: /*Unimplemented*/Option<Fundamental: Pointer>) {
     //    unsafe { TODO: call ffi::gst_player_video_overlay_video_renderer_set_window_handle() }
     //}
 
@@ -73,27 +73,27 @@ impl PlayerVideoOverlayVideoRenderer {
         }
     }
 
-    //pub fn new<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(window_handle: P) -> Option<PlayerVideoRenderer> {
+    //pub fn new(window_handle: /*Unimplemented*/Option<Fundamental: Pointer>) -> Option<PlayerVideoRenderer> {
     //    unsafe { TODO: call ffi::gst_player_video_overlay_video_renderer_new() }
     //}
 
-    //pub fn new_with_sink<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>, Q: IsA<gst::Element>>(window_handle: P, video_sink: &Q) -> Option<PlayerVideoRenderer> {
+    //pub fn new_with_sink<P: IsA<gst::Element>>(window_handle: /*Unimplemented*/Option<Fundamental: Pointer>, video_sink: &P) -> Option<PlayerVideoRenderer> {
     //    unsafe { TODO: call ffi::gst_player_video_overlay_video_renderer_new_with_sink() }
     //}
 
     pub fn connect_property_video_sink_notify<F: Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::video-sink\0".as_ptr() as *const _,
-                transmute(notify_video_sink_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_video_sink_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_window_handle_notify<F: Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::window-handle\0".as_ptr() as *const _,
-                transmute(notify_window_handle_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_window_handle_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -101,12 +101,12 @@ impl PlayerVideoOverlayVideoRenderer {
 unsafe impl Send for PlayerVideoOverlayVideoRenderer {}
 unsafe impl Sync for PlayerVideoOverlayVideoRenderer {}
 
-unsafe extern "C" fn notify_video_sink_trampoline(this: *mut ffi::GstPlayerVideoOverlayVideoRenderer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_video_sink_trampoline<F: Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>(this: *mut ffi::GstPlayerVideoOverlayVideoRenderer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_window_handle_trampoline(this: *mut ffi::GstPlayerVideoOverlayVideoRenderer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_window_handle_trampoline<F: Fn(&PlayerVideoOverlayVideoRenderer) + Send + Sync + 'static>(this: *mut ffi::GstPlayerVideoOverlayVideoRenderer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-player/src/auto/versions.txt b/gstreamer-player/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-player/src/auto/versions.txt
+++ b/gstreamer-player/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_auth.rs b/gstreamer-rtsp-server/src/auto/rtsp_auth.rs
index 4e9152c72..39f3f328d 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_auth.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_auth.rs
@@ -181,15 +181,15 @@ impl<O: IsA<RTSPAuth>> RTSPAuthExt for O {
 
     fn connect_accept_certificate<F: Fn(&Self, &gio::TlsConnection, &gio::TlsCertificate, gio::TlsCertificateFlags) -> bool + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &gio::TlsConnection, &gio::TlsCertificate, gio::TlsCertificateFlags) -> bool + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"accept-certificate\0".as_ptr() as *const _,
-                transmute(accept_certificate_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(accept_certificate_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn accept_certificate_trampoline<P>(this: *mut ffi::GstRTSPAuth, connection: *mut gio_ffi::GTlsConnection, peer_cert: *mut gio_ffi::GTlsCertificate, errors: gio_ffi::GTlsCertificateFlags, f: glib_ffi::gpointer) -> glib_ffi::gboolean
+unsafe extern "C" fn accept_certificate_trampoline<P, F: Fn(&P, &gio::TlsConnection, &gio::TlsCertificate, gio::TlsCertificateFlags) -> bool + Send + Sync + 'static>(this: *mut ffi::GstRTSPAuth, connection: *mut gio_ffi::GTlsConnection, peer_cert: *mut gio_ffi::GTlsCertificate, errors: gio_ffi::GTlsCertificateFlags, f: glib_ffi::gpointer) -> glib_ffi::gboolean
 where P: IsA<RTSPAuth> {
-    let f: &&(Fn(&P, &gio::TlsConnection, &gio::TlsCertificate, gio::TlsCertificateFlags) -> bool + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPAuth::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(connection), &from_glib_borrow(peer_cert), from_glib(errors)).to_glib()
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_client.rs b/gstreamer-rtsp-server/src/auto/rtsp_client.rs
index 0e0560331..ec095d26e 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_client.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_client.rs
@@ -70,7 +70,7 @@ pub trait RTSPClientExt: 'static {
 
     //fn send_message<'a, P: IsA<RTSPSession> + 'a, Q: Into<Option<&'a P>>>(&self, session: Q, message: /*Ignored*/&mut gst_rtsp::RTSPMessage) -> gst_rtsp::RTSPResult;
 
-    //fn session_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPClientSessionFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSession>;
+    //fn session_filter(&self, func: /*Unimplemented*/Fn(&RTSPClient, &RTSPSession) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSession>;
 
     fn set_auth<'a, P: IsA<RTSPAuth> + 'a, Q: Into<Option<&'a P>>>(&self, auth: Q);
 
@@ -78,7 +78,7 @@ pub trait RTSPClientExt: 'static {
 
     fn set_mount_points<'a, P: IsA<RTSPMountPoints> + 'a, Q: Into<Option<&'a P>>>(&self, mounts: Q);
 
-    //fn set_send_func<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, func: /*Unknown conversion*//*Unimplemented*/RTSPClientSendFunc, notify: P);
+    //fn set_send_func(&self, func: /*Unimplemented*/Fn(&RTSPClient, /*Ignored*/gst_rtsp::RTSPMessage, bool) -> bool, user_data: /*Unimplemented*/Option<Fundamental: Pointer>);
 
     fn set_session_pool<'a, P: IsA<RTSPSessionPool> + 'a, Q: Into<Option<&'a P>>>(&self, pool: Q);
 
@@ -198,7 +198,7 @@ impl<O: IsA<RTSPClient>> RTSPClientExt for O {
     //    unsafe { TODO: call ffi::gst_rtsp_client_send_message() }
     //}
 
-    //fn session_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPClientSessionFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSession> {
+    //fn session_filter(&self, func: /*Unimplemented*/Fn(&RTSPClient, &RTSPSession) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSession> {
     //    unsafe { TODO: call ffi::gst_rtsp_client_session_filter() }
     //}
 
@@ -220,7 +220,7 @@ impl<O: IsA<RTSPClient>> RTSPClientExt for O {
         }
     }
 
-    //fn set_send_func<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, func: /*Unknown conversion*//*Unimplemented*/RTSPClientSendFunc, notify: P) {
+    //fn set_send_func(&self, func: /*Unimplemented*/Fn(&RTSPClient, /*Ignored*/gst_rtsp::RTSPMessage, bool) -> bool, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) {
     //    unsafe { TODO: call ffi::gst_rtsp_client_set_send_func() }
     //}
 
@@ -254,9 +254,9 @@ impl<O: IsA<RTSPClient>> RTSPClientExt for O {
 
     fn connect_announce_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"announce-request\0".as_ptr() as *const _,
-                transmute(announce_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(announce_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
@@ -266,163 +266,163 @@ impl<O: IsA<RTSPClient>> RTSPClientExt for O {
 
     fn connect_closed<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"closed\0".as_ptr() as *const _,
-                transmute(closed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(closed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_describe_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"describe-request\0".as_ptr() as *const _,
-                transmute(describe_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(describe_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_get_parameter_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"get-parameter-request\0".as_ptr() as *const _,
-                transmute(get_parameter_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(get_parameter_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_handle_response<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"handle-response\0".as_ptr() as *const _,
-                transmute(handle_response_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(handle_response_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_new_session<F: Fn(&Self, &RTSPSession) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPSession) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"new-session\0".as_ptr() as *const _,
-                transmute(new_session_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(new_session_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_options_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"options-request\0".as_ptr() as *const _,
-                transmute(options_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(options_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_pause_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pause-request\0".as_ptr() as *const _,
-                transmute(pause_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pause_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_play_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"play-request\0".as_ptr() as *const _,
-                transmute(play_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(play_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_announce_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-announce-request\0".as_ptr() as *const _,
-                transmute(pre_announce_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_announce_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_describe_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-describe-request\0".as_ptr() as *const _,
-                transmute(pre_describe_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_describe_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_get_parameter_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-get-parameter-request\0".as_ptr() as *const _,
-                transmute(pre_get_parameter_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_get_parameter_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_options_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-options-request\0".as_ptr() as *const _,
-                transmute(pre_options_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_options_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_pause_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-pause-request\0".as_ptr() as *const _,
-                transmute(pre_pause_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_pause_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_play_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-play-request\0".as_ptr() as *const _,
-                transmute(pre_play_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_play_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_record_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-record-request\0".as_ptr() as *const _,
-                transmute(pre_record_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_record_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_set_parameter_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-set-parameter-request\0".as_ptr() as *const _,
-                transmute(pre_set_parameter_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_set_parameter_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_setup_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-setup-request\0".as_ptr() as *const _,
-                transmute(pre_setup_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_setup_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_12", feature = "dox"))]
     fn connect_pre_teardown_request<F: Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pre-teardown-request\0".as_ptr() as *const _,
-                transmute(pre_teardown_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pre_teardown_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_record_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"record-request\0".as_ptr() as *const _,
-                transmute(record_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(record_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
@@ -432,215 +432,215 @@ impl<O: IsA<RTSPClient>> RTSPClientExt for O {
 
     fn connect_set_parameter_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"set-parameter-request\0".as_ptr() as *const _,
-                transmute(set_parameter_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(set_parameter_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_setup_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"setup-request\0".as_ptr() as *const _,
-                transmute(setup_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(setup_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_teardown_request<F: Fn(&Self, &RTSPContext) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPContext) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"teardown-request\0".as_ptr() as *const _,
-                transmute(teardown_request_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(teardown_request_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_drop_backlog_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::drop-backlog\0".as_ptr() as *const _,
-                transmute(notify_drop_backlog_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_drop_backlog_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_mount_points_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mount-points\0".as_ptr() as *const _,
-                transmute(notify_mount_points_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mount_points_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_session_pool_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::session-pool\0".as_ptr() as *const _,
-                transmute(notify_session_pool_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_session_pool_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn announce_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn announce_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn closed_trampoline<P>(this: *mut ffi::GstRTSPClient, f: glib_ffi::gpointer)
+unsafe extern "C" fn closed_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn describe_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn describe_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn get_parameter_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn get_parameter_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn handle_response_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn handle_response_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn new_session_trampoline<P>(this: *mut ffi::GstRTSPClient, object: *mut ffi::GstRTSPSession, f: glib_ffi::gpointer)
+unsafe extern "C" fn new_session_trampoline<P, F: Fn(&P, &RTSPSession) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, object: *mut ffi::GstRTSPSession, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPSession) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn options_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn options_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn pause_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn pause_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn play_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn play_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_announce_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_announce_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_describe_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_describe_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_get_parameter_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_get_parameter_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_options_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_options_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_pause_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_pause_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_play_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_play_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_record_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_record_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_set_parameter_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_set_parameter_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_setup_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_setup_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
 #[cfg(any(feature = "v1_12", feature = "dox"))]
-unsafe extern "C" fn pre_teardown_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
+unsafe extern "C" fn pre_teardown_request_trampoline<P, F: Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer) -> gst_rtsp_ffi::GstRTSPStatusCode
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) -> gst_rtsp::RTSPStatusCode + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx)).to_glib()
 }
 
-unsafe extern "C" fn record_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn record_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn set_parameter_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn set_parameter_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn setup_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn setup_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn teardown_request_trampoline<P>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
+unsafe extern "C" fn teardown_request_trampoline<P, F: Fn(&P, &RTSPContext) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, ctx: *mut ffi::GstRTSPContext, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P, &RTSPContext) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(ctx))
 }
 
-unsafe extern "C" fn notify_drop_backlog_trampoline<P>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_drop_backlog_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_mount_points_trampoline<P>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mount_points_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_session_pool_trampoline<P>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_session_pool_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPClient, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPClient> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPClient::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_media.rs b/gstreamer-rtsp-server/src/auto/rtsp_media.rs
index 554fd1ccb..66c0c6ac5 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_media.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_media.rs
@@ -107,7 +107,7 @@ pub trait RTSPMediaExt: 'static {
 
     fn n_streams(&self) -> u32;
 
-    //fn prepare<'a, P: Into<Option<&'a /*Ignored*/RTSPThread>>>(&self, thread: P) -> bool;
+    //fn prepare(&self, thread: /*Ignored*/Option<&mut RTSPThread>) -> bool;
 
     //fn seek(&self, range: /*Ignored*/&mut gst_rtsp::RTSPTimeRange) -> bool;
 
@@ -127,7 +127,7 @@ pub trait RTSPMediaExt: 'static {
 
     fn set_multicast_iface<'a, P: Into<Option<&'a str>>>(&self, multicast_iface: P);
 
-    //fn set_permissions<'a, P: Into<Option<&'a /*Ignored*/RTSPPermissions>>>(&self, permissions: P);
+    //fn set_permissions(&self, permissions: /*Ignored*/Option<&mut RTSPPermissions>);
 
     fn set_pipeline_state(&self, state: gst::State);
 
@@ -377,7 +377,7 @@ impl<O: IsA<RTSPMedia>> RTSPMediaExt for O {
         }
     }
 
-    //fn prepare<'a, P: Into<Option<&'a /*Ignored*/RTSPThread>>>(&self, thread: P) -> bool {
+    //fn prepare(&self, thread: /*Ignored*/Option<&mut RTSPThread>) -> bool {
     //    unsafe { TODO: call ffi::gst_rtsp_media_prepare() }
     //}
 
@@ -432,7 +432,7 @@ impl<O: IsA<RTSPMedia>> RTSPMediaExt for O {
         }
     }
 
-    //fn set_permissions<'a, P: Into<Option<&'a /*Ignored*/RTSPPermissions>>>(&self, permissions: P) {
+    //fn set_permissions(&self, permissions: /*Ignored*/Option<&mut RTSPPermissions>) {
     //    unsafe { TODO: call ffi::gst_rtsp_media_set_permissions() }
     //}
 
@@ -574,253 +574,253 @@ impl<O: IsA<RTSPMedia>> RTSPMediaExt for O {
 
     fn connect_new_state<F: Fn(&Self, i32) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, i32) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"new-state\0".as_ptr() as *const _,
-                transmute(new_state_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(new_state_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_new_stream<F: Fn(&Self, &RTSPStream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPStream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"new-stream\0".as_ptr() as *const _,
-                transmute(new_stream_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(new_stream_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_prepared<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"prepared\0".as_ptr() as *const _,
-                transmute(prepared_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(prepared_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_removed_stream<F: Fn(&Self, &RTSPStream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPStream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"removed-stream\0".as_ptr() as *const _,
-                transmute(removed_stream_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(removed_stream_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_target_state<F: Fn(&Self, i32) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, i32) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"target-state\0".as_ptr() as *const _,
-                transmute(target_state_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(target_state_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_unprepared<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"unprepared\0".as_ptr() as *const _,
-                transmute(unprepared_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(unprepared_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_buffer_size_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::buffer-size\0".as_ptr() as *const _,
-                transmute(notify_buffer_size_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_buffer_size_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_clock_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::clock\0".as_ptr() as *const _,
-                transmute(notify_clock_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_clock_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_eos_shutdown_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::eos-shutdown\0".as_ptr() as *const _,
-                transmute(notify_eos_shutdown_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_eos_shutdown_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_latency_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::latency\0".as_ptr() as *const _,
-                transmute(notify_latency_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_latency_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_profiles_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::profiles\0".as_ptr() as *const _,
-                transmute(notify_profiles_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_profiles_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_protocols_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::protocols\0".as_ptr() as *const _,
-                transmute(notify_protocols_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_protocols_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_reusable_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::reusable\0".as_ptr() as *const _,
-                transmute(notify_reusable_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_reusable_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_shared_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::shared\0".as_ptr() as *const _,
-                transmute(notify_shared_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_shared_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_stop_on_disconnect_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::stop-on-disconnect\0".as_ptr() as *const _,
-                transmute(notify_stop_on_disconnect_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_stop_on_disconnect_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_suspend_mode_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::suspend-mode\0".as_ptr() as *const _,
-                transmute(notify_suspend_mode_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_suspend_mode_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_time_provider_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::time-provider\0".as_ptr() as *const _,
-                transmute(notify_time_provider_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_time_provider_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_transport_mode_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::transport-mode\0".as_ptr() as *const _,
-                transmute(notify_transport_mode_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_transport_mode_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn new_state_trampoline<P>(this: *mut ffi::GstRTSPMedia, object: libc::c_int, f: glib_ffi::gpointer)
+unsafe extern "C" fn new_state_trampoline<P, F: Fn(&P, i32) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, object: libc::c_int, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P, i32) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast(), object)
 }
 
-unsafe extern "C" fn new_stream_trampoline<P>(this: *mut ffi::GstRTSPMedia, object: *mut ffi::GstRTSPStream, f: glib_ffi::gpointer)
+unsafe extern "C" fn new_stream_trampoline<P, F: Fn(&P, &RTSPStream) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, object: *mut ffi::GstRTSPStream, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P, &RTSPStream) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn prepared_trampoline<P>(this: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
+unsafe extern "C" fn prepared_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn removed_stream_trampoline<P>(this: *mut ffi::GstRTSPMedia, object: *mut ffi::GstRTSPStream, f: glib_ffi::gpointer)
+unsafe extern "C" fn removed_stream_trampoline<P, F: Fn(&P, &RTSPStream) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, object: *mut ffi::GstRTSPStream, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P, &RTSPStream) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn target_state_trampoline<P>(this: *mut ffi::GstRTSPMedia, object: libc::c_int, f: glib_ffi::gpointer)
+unsafe extern "C" fn target_state_trampoline<P, F: Fn(&P, i32) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, object: libc::c_int, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P, i32) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast(), object)
 }
 
-unsafe extern "C" fn unprepared_trampoline<P>(this: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
+unsafe extern "C" fn unprepared_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_buffer_size_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_buffer_size_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_clock_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_clock_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_eos_shutdown_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_eos_shutdown_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_latency_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_latency_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_profiles_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_profiles_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_protocols_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_protocols_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_reusable_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_reusable_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_shared_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_shared_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_stop_on_disconnect_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_stop_on_disconnect_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_suspend_mode_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_suspend_mode_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_time_provider_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_time_provider_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_transport_mode_trampoline<P>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_transport_mode_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMedia, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMedia> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMedia::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_media_factory.rs b/gstreamer-rtsp-server/src/auto/rtsp_media_factory.rs
index ceffaddb2..fd3af286a 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_media_factory.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_media_factory.rs
@@ -109,7 +109,7 @@ pub trait RTSPMediaFactoryExt: 'static {
 
     fn set_multicast_iface<'a, P: Into<Option<&'a str>>>(&self, multicast_iface: P);
 
-    //fn set_permissions<'a, P: Into<Option<&'a /*Ignored*/RTSPPermissions>>>(&self, permissions: P);
+    //fn set_permissions(&self, permissions: /*Ignored*/Option<&mut RTSPPermissions>);
 
     fn set_profiles(&self, profiles: gst_rtsp::RTSPProfile);
 
@@ -328,7 +328,7 @@ impl<O: IsA<RTSPMediaFactory>> RTSPMediaFactoryExt for O {
         }
     }
 
-    //fn set_permissions<'a, P: Into<Option<&'a /*Ignored*/RTSPPermissions>>>(&self, permissions: P) {
+    //fn set_permissions(&self, permissions: /*Ignored*/Option<&mut RTSPPermissions>) {
     //    unsafe { TODO: call ffi::gst_rtsp_media_factory_set_permissions() }
     //}
 
@@ -406,183 +406,183 @@ impl<O: IsA<RTSPMediaFactory>> RTSPMediaFactoryExt for O {
 
     fn connect_media_configure<F: Fn(&Self, &RTSPMedia) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPMedia) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"media-configure\0".as_ptr() as *const _,
-                transmute(media_configure_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(media_configure_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_media_constructed<F: Fn(&Self, &RTSPMedia) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPMedia) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"media-constructed\0".as_ptr() as *const _,
-                transmute(media_constructed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(media_constructed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_buffer_size_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::buffer-size\0".as_ptr() as *const _,
-                transmute(notify_buffer_size_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_buffer_size_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_clock_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::clock\0".as_ptr() as *const _,
-                transmute(notify_clock_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_clock_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_eos_shutdown_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::eos-shutdown\0".as_ptr() as *const _,
-                transmute(notify_eos_shutdown_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_eos_shutdown_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_latency_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::latency\0".as_ptr() as *const _,
-                transmute(notify_latency_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_latency_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_launch_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::launch\0".as_ptr() as *const _,
-                transmute(notify_launch_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_launch_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_profiles_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::profiles\0".as_ptr() as *const _,
-                transmute(notify_profiles_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_profiles_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_protocols_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::protocols\0".as_ptr() as *const _,
-                transmute(notify_protocols_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_protocols_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_shared_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::shared\0".as_ptr() as *const _,
-                transmute(notify_shared_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_shared_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_stop_on_disconnect_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::stop-on-disconnect\0".as_ptr() as *const _,
-                transmute(notify_stop_on_disconnect_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_stop_on_disconnect_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_suspend_mode_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::suspend-mode\0".as_ptr() as *const _,
-                transmute(notify_suspend_mode_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_suspend_mode_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_transport_mode_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::transport-mode\0".as_ptr() as *const _,
-                transmute(notify_transport_mode_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_transport_mode_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn media_configure_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, object: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
+unsafe extern "C" fn media_configure_trampoline<P, F: Fn(&P, &RTSPMedia) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, object: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P, &RTSPMedia) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn media_constructed_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, object: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
+unsafe extern "C" fn media_constructed_trampoline<P, F: Fn(&P, &RTSPMedia) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, object: *mut ffi::GstRTSPMedia, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P, &RTSPMedia) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn notify_buffer_size_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_buffer_size_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_clock_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_clock_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_eos_shutdown_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_eos_shutdown_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_latency_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_latency_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_launch_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_launch_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_profiles_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_profiles_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_protocols_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_protocols_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_shared_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_shared_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_stop_on_disconnect_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_stop_on_disconnect_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_suspend_mode_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_suspend_mode_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_transport_mode_trampoline<P>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_transport_mode_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactory, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactory> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactory::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_media_factory_uri.rs b/gstreamer-rtsp-server/src/auto/rtsp_media_factory_uri.rs
index f2df706e8..4f0ebe5c8 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_media_factory_uri.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_media_factory_uri.rs
@@ -88,29 +88,29 @@ impl<O: IsA<RTSPMediaFactoryURI>> RTSPMediaFactoryURIExt for O {
 
     fn connect_property_uri_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::uri\0".as_ptr() as *const _,
-                transmute(notify_uri_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_uri_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_use_gstpay_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::use-gstpay\0".as_ptr() as *const _,
-                transmute(notify_use_gstpay_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_use_gstpay_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_uri_trampoline<P>(this: *mut ffi::GstRTSPMediaFactoryURI, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_uri_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactoryURI, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactoryURI> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactoryURI::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_use_gstpay_trampoline<P>(this: *mut ffi::GstRTSPMediaFactoryURI, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_use_gstpay_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPMediaFactoryURI, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPMediaFactoryURI> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPMediaFactoryURI::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_server.rs b/gstreamer-rtsp-server/src/auto/rtsp_server.rs
index d4af8cb77..03a491282 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_server.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_server.rs
@@ -58,7 +58,7 @@ unsafe impl Sync for RTSPServer {}
 pub const NONE_RTSP_SERVER: Option<&RTSPServer> = None;
 
 pub trait RTSPServerExt: 'static {
-    //fn client_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPServerClientFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPClient>;
+    //fn client_filter(&self, func: /*Unimplemented*/Fn(&RTSPServer, &RTSPClient) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPClient>;
 
     fn create_socket<'a, P: IsA<gio::Cancellable> + 'a, Q: Into<Option<&'a P>>>(&self, cancellable: Q) -> Result<gio::Socket, Error>;
 
@@ -112,7 +112,7 @@ pub trait RTSPServerExt: 'static {
 }
 
 impl<O: IsA<RTSPServer>> RTSPServerExt for O {
-    //fn client_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPServerClientFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPClient> {
+    //fn client_filter(&self, func: /*Unimplemented*/Fn(&RTSPServer, &RTSPClient) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPClient> {
     //    unsafe { TODO: call ffi::gst_rtsp_server_client_filter() }
     //}
 
@@ -237,99 +237,99 @@ impl<O: IsA<RTSPServer>> RTSPServerExt for O {
 
     fn connect_client_connected<F: Fn(&Self, &RTSPClient) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPClient) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"client-connected\0".as_ptr() as *const _,
-                transmute(client_connected_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(client_connected_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_address_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::address\0".as_ptr() as *const _,
-                transmute(notify_address_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_address_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_backlog_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::backlog\0".as_ptr() as *const _,
-                transmute(notify_backlog_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_backlog_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_bound_port_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::bound-port\0".as_ptr() as *const _,
-                transmute(notify_bound_port_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_bound_port_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_mount_points_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::mount-points\0".as_ptr() as *const _,
-                transmute(notify_mount_points_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_mount_points_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_service_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::service\0".as_ptr() as *const _,
-                transmute(notify_service_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_service_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_session_pool_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::session-pool\0".as_ptr() as *const _,
-                transmute(notify_session_pool_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_session_pool_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn client_connected_trampoline<P>(this: *mut ffi::GstRTSPServer, object: *mut ffi::GstRTSPClient, f: glib_ffi::gpointer)
+unsafe extern "C" fn client_connected_trampoline<P, F: Fn(&P, &RTSPClient) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, object: *mut ffi::GstRTSPClient, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P, &RTSPClient) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn notify_address_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_address_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_backlog_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_backlog_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_bound_port_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_bound_port_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_mount_points_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_mount_points_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_service_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_service_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_session_pool_trampoline<P>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_session_pool_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPServer, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPServer> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPServer::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_session.rs b/gstreamer-rtsp-server/src/auto/rtsp_session.rs
index 42e3e54c2..68461ae2f 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_session.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_session.rs
@@ -44,7 +44,7 @@ pub const NONE_RTSP_SESSION: Option<&RTSPSession> = None;
 pub trait RTSPSessionExt: 'static {
     fn allow_expire(&self);
 
-    //fn filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPSessionFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSessionMedia>;
+    //fn filter(&self, func: /*Unimplemented*/Fn(&RTSPSession, &RTSPSessionMedia) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSessionMedia>;
 
     fn get_header(&self) -> Option<GString>;
 
@@ -88,7 +88,7 @@ impl<O: IsA<RTSPSession>> RTSPSessionExt for O {
         }
     }
 
-    //fn filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPSessionFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSessionMedia> {
+    //fn filter(&self, func: /*Unimplemented*/Fn(&RTSPSession, &RTSPSessionMedia) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSessionMedia> {
     //    unsafe { TODO: call ffi::gst_rtsp_session_filter() }
     //}
 
@@ -184,29 +184,29 @@ impl<O: IsA<RTSPSession>> RTSPSessionExt for O {
 
     fn connect_property_timeout_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::timeout\0".as_ptr() as *const _,
-                transmute(notify_timeout_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_timeout_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_timeout_always_visible_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::timeout-always-visible\0".as_ptr() as *const _,
-                transmute(notify_timeout_always_visible_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_timeout_always_visible_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_timeout_trampoline<P>(this: *mut ffi::GstRTSPSession, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_timeout_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPSession, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPSession> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPSession::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_timeout_always_visible_trampoline<P>(this: *mut ffi::GstRTSPSession, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_timeout_always_visible_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPSession, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPSession> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPSession::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_session_pool.rs b/gstreamer-rtsp-server/src/auto/rtsp_session_pool.rs
index 0071ce826..0dba71cac 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_session_pool.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_session_pool.rs
@@ -47,7 +47,7 @@ pub trait RTSPSessionPoolExt: 'static {
 
     fn create(&self) -> Option<RTSPSession>;
 
-    //fn filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPSessionPoolFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSession>;
+    //fn filter(&self, func: /*Unimplemented*/Fn(&RTSPSessionPool, &RTSPSession) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSession>;
 
     fn find(&self, sessionid: &str) -> Option<RTSPSession>;
 
@@ -77,7 +77,7 @@ impl<O: IsA<RTSPSessionPool>> RTSPSessionPoolExt for O {
         }
     }
 
-    //fn filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPSessionPoolFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPSession> {
+    //fn filter(&self, func: /*Unimplemented*/Fn(&RTSPSessionPool, &RTSPSession) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPSession> {
     //    unsafe { TODO: call ffi::gst_rtsp_session_pool_filter() }
     //}
 
@@ -113,29 +113,29 @@ impl<O: IsA<RTSPSessionPool>> RTSPSessionPoolExt for O {
 
     fn connect_session_removed<F: Fn(&Self, &RTSPSession) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &RTSPSession) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"session-removed\0".as_ptr() as *const _,
-                transmute(session_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(session_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_max_sessions_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-sessions\0".as_ptr() as *const _,
-                transmute(notify_max_sessions_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_sessions_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn session_removed_trampoline<P>(this: *mut ffi::GstRTSPSessionPool, object: *mut ffi::GstRTSPSession, f: glib_ffi::gpointer)
+unsafe extern "C" fn session_removed_trampoline<P, F: Fn(&P, &RTSPSession) + Send + Sync + 'static>(this: *mut ffi::GstRTSPSessionPool, object: *mut ffi::GstRTSPSession, f: glib_ffi::gpointer)
 where P: IsA<RTSPSessionPool> {
-    let f: &&(Fn(&P, &RTSPSession) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPSessionPool::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn notify_max_sessions_trampoline<P>(this: *mut ffi::GstRTSPSessionPool, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_sessions_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPSessionPool, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPSessionPool> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPSessionPool::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_stream.rs b/gstreamer-rtsp-server/src/auto/rtsp_stream.rs
index 44d6ce099..501569a14 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_stream.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_stream.rs
@@ -164,7 +164,7 @@ pub trait RTSPStreamExt: 'static {
 
     fn set_seqnum_offset(&self, seqnum: u16);
 
-    //fn transport_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPStreamTransportFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPStreamTransport>;
+    //fn transport_filter(&self, func: /*Unimplemented*/Fn(&RTSPStream, &RTSPStreamTransport) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPStreamTransport>;
 
     fn unblock_linked(&self) -> bool;
 
@@ -539,7 +539,7 @@ impl<O: IsA<RTSPStream>> RTSPStreamExt for O {
         }
     }
 
-    //fn transport_filter<'a, P: Into<Option<&'a /*Unimplemented*/RTSPStreamTransportFilterFunc>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: P, user_data: Q) -> Vec<RTSPStreamTransport> {
+    //fn transport_filter(&self, func: /*Unimplemented*/Fn(&RTSPStream, &RTSPStreamTransport) -> /*Ignored*/RTSPFilterResult, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> Vec<RTSPStreamTransport> {
     //    unsafe { TODO: call ffi::gst_rtsp_stream_transport_filter() }
     //}
 
@@ -558,71 +558,71 @@ impl<O: IsA<RTSPStream>> RTSPStreamExt for O {
 
     fn connect_new_rtcp_encoder<F: Fn(&Self, &gst::Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &gst::Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"new-rtcp-encoder\0".as_ptr() as *const _,
-                transmute(new_rtcp_encoder_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(new_rtcp_encoder_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_new_rtp_encoder<F: Fn(&Self, &gst::Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &gst::Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"new-rtp-encoder\0".as_ptr() as *const _,
-                transmute(new_rtp_encoder_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(new_rtp_encoder_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_control_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::control\0".as_ptr() as *const _,
-                transmute(notify_control_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_control_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_profiles_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::profiles\0".as_ptr() as *const _,
-                transmute(notify_profiles_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_profiles_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_protocols_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::protocols\0".as_ptr() as *const _,
-                transmute(notify_protocols_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_protocols_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn new_rtcp_encoder_trampoline<P>(this: *mut ffi::GstRTSPStream, object: *mut gst_ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn new_rtcp_encoder_trampoline<P, F: Fn(&P, &gst::Element) + Send + Sync + 'static>(this: *mut ffi::GstRTSPStream, object: *mut gst_ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<RTSPStream> {
-    let f: &&(Fn(&P, &gst::Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPStream::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn new_rtp_encoder_trampoline<P>(this: *mut ffi::GstRTSPStream, object: *mut gst_ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn new_rtp_encoder_trampoline<P, F: Fn(&P, &gst::Element) + Send + Sync + 'static>(this: *mut ffi::GstRTSPStream, object: *mut gst_ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<RTSPStream> {
-    let f: &&(Fn(&P, &gst::Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPStream::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object))
 }
 
-unsafe extern "C" fn notify_control_trampoline<P>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_control_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPStream> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPStream::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_profiles_trampoline<P>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_profiles_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPStream> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPStream::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_protocols_trampoline<P>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_protocols_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPStream> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPStream::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_stream_transport.rs b/gstreamer-rtsp-server/src/auto/rtsp_stream_transport.rs
index ae71cd2bd..f6943edfa 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_stream_transport.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_stream_transport.rs
@@ -10,6 +10,7 @@ use glib::object::IsA;
 use glib::translate::*;
 use gst;
 use gst_rtsp;
+use std::boxed::Box as Box_;
 
 glib_wrapper! {
     pub struct RTSPStreamTransport(Object<ffi::GstRTSPStreamTransport, ffi::GstRTSPStreamTransportClass, RTSPStreamTransportClass>);
@@ -46,9 +47,9 @@ pub trait RTSPStreamTransportExt: 'static {
 
     fn set_active(&self, active: bool) -> Result<(), glib::error::BoolError>;
 
-    //fn set_callbacks<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, send_rtp: /*Unknown conversion*//*Unimplemented*/RTSPSendFunc, send_rtcp: /*Unknown conversion*//*Unimplemented*/RTSPSendFunc, notify: P);
+    //fn set_callbacks<P: Fn(&gst::Buffer, u8) -> bool + 'static, Q: Fn(&gst::Buffer, u8) -> bool + 'static>(&self, send_rtp: P, send_rtcp: Q);
 
-    //fn set_keepalive<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, keep_alive: /*Unknown conversion*//*Unimplemented*/RTSPKeepAliveFunc, notify: P);
+    fn set_keepalive<P: Fn() + 'static>(&self, keep_alive: P);
 
     fn set_timed_out(&self, timedout: bool);
 
@@ -110,13 +111,26 @@ impl<O: IsA<RTSPStreamTransport>> RTSPStreamTransportExt for O {
         }
     }
 
-    //fn set_callbacks<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, send_rtp: /*Unknown conversion*//*Unimplemented*/RTSPSendFunc, send_rtcp: /*Unknown conversion*//*Unimplemented*/RTSPSendFunc, notify: P) {
+    //fn set_callbacks<P: Fn(&gst::Buffer, u8) -> bool + 'static, Q: Fn(&gst::Buffer, u8) -> bool + 'static>(&self, send_rtp: P, send_rtcp: Q) {
     //    unsafe { TODO: call ffi::gst_rtsp_stream_transport_set_callbacks() }
     //}
 
-    //fn set_keepalive<'a, P: Into<Option<&'a /*Ignored*/glib::DestroyNotify>>>(&self, keep_alive: /*Unknown conversion*//*Unimplemented*/RTSPKeepAliveFunc, notify: P) {
-    //    unsafe { TODO: call ffi::gst_rtsp_stream_transport_set_keepalive() }
-    //}
+    fn set_keepalive<P: Fn() + 'static>(&self, keep_alive: P) {
+        let keep_alive_data: Box_<P> = Box::new(keep_alive);
+        unsafe extern "C" fn keep_alive_func<P: Fn() + 'static>(user_data: glib_ffi::gpointer) {
+            let callback: &P = &*(user_data as *mut _);
+            (*callback)();
+        }
+        let keep_alive = Some(keep_alive_func::<P> as _);
+        unsafe extern "C" fn notify_func<P: Fn() + 'static>(data: glib_ffi::gpointer) {
+            let _callback: Box_<P> = Box_::from_raw(data as *mut _);
+        }
+        let destroy_call3 = Some(notify_func::<P> as _);
+        let super_callback0: Box_<P> = keep_alive_data;
+        unsafe {
+            ffi::gst_rtsp_stream_transport_set_keepalive(self.as_ref().to_glib_none().0, keep_alive, Box::into_raw(super_callback0) as *mut _, destroy_call3);
+        }
+    }
 
     fn set_timed_out(&self, timedout: bool) {
         unsafe {
diff --git a/gstreamer-rtsp-server/src/auto/rtsp_thread_pool.rs b/gstreamer-rtsp-server/src/auto/rtsp_thread_pool.rs
index 3be4853fc..ae0e5911c 100644
--- a/gstreamer-rtsp-server/src/auto/rtsp_thread_pool.rs
+++ b/gstreamer-rtsp-server/src/auto/rtsp_thread_pool.rs
@@ -76,15 +76,15 @@ impl<O: IsA<RTSPThreadPool>> RTSPThreadPoolExt for O {
 
     fn connect_property_max_threads_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::max-threads\0".as_ptr() as *const _,
-                transmute(notify_max_threads_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_max_threads_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_max_threads_trampoline<P>(this: *mut ffi::GstRTSPThreadPool, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_max_threads_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstRTSPThreadPool, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<RTSPThreadPool> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&RTSPThreadPool::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer-rtsp-server/src/auto/versions.txt b/gstreamer-rtsp-server/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-rtsp-server/src/auto/versions.txt
+++ b/gstreamer-rtsp-server/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-rtsp/src/auto/versions.txt b/gstreamer-rtsp/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-rtsp/src/auto/versions.txt
+++ b/gstreamer-rtsp/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-sdp/src/auto/mikey_payload.rs b/gstreamer-sdp/src/auto/mikey_payload.rs
index 3e1bd03e0..9a9968056 100644
--- a/gstreamer-sdp/src/auto/mikey_payload.rs
+++ b/gstreamer-sdp/src/auto/mikey_payload.rs
@@ -24,7 +24,7 @@ glib_wrapper! {
 }
 
 impl MIKEYPayload {
-    pub fn new(type_: MIKEYPayloadType) -> MIKEYPayload {
+    pub fn new(type_: MIKEYPayloadType) -> Option<MIKEYPayload> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gst_mikey_payload_new(type_.to_glib()))
diff --git a/gstreamer-sdp/src/auto/versions.txt b/gstreamer-sdp/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-sdp/src/auto/versions.txt
+++ b/gstreamer-sdp/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-video/src/auto/versions.txt b/gstreamer-video/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-video/src/auto/versions.txt
+++ b/gstreamer-video/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-webrtc/src/auto/versions.txt b/gstreamer-webrtc/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer-webrtc/src/auto/versions.txt
+++ b/gstreamer-webrtc/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)
diff --git a/gstreamer-webrtc/src/auto/web_rtcdtls_transport.rs b/gstreamer-webrtc/src/auto/web_rtcdtls_transport.rs
index d2e04e9ac..678767e65 100644
--- a/gstreamer-webrtc/src/auto/web_rtcdtls_transport.rs
+++ b/gstreamer-webrtc/src/auto/web_rtcdtls_transport.rs
@@ -110,41 +110,41 @@ impl WebRTCDTLSTransport {
 
     pub fn connect_property_certificate_notify<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::certificate\0".as_ptr() as *const _,
-                transmute(notify_certificate_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_certificate_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_client_notify<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::client\0".as_ptr() as *const _,
-                transmute(notify_client_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_client_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_remote_certificate_notify<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::remote-certificate\0".as_ptr() as *const _,
-                transmute(notify_remote_certificate_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_remote_certificate_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_state_notify<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::state\0".as_ptr() as *const _,
-                transmute(notify_state_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_state_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_transport_notify<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::transport\0".as_ptr() as *const _,
-                transmute(notify_transport_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_transport_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -152,27 +152,27 @@ impl WebRTCDTLSTransport {
 unsafe impl Send for WebRTCDTLSTransport {}
 unsafe impl Sync for WebRTCDTLSTransport {}
 
-unsafe extern "C" fn notify_certificate_trampoline(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCDTLSTransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_certificate_trampoline<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_client_trampoline(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCDTLSTransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_client_trampoline<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_remote_certificate_trampoline(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCDTLSTransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_remote_certificate_trampoline<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_state_trampoline(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCDTLSTransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_state_trampoline<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_transport_trampoline(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCDTLSTransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_transport_trampoline<F: Fn(&WebRTCDTLSTransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCDTLSTransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer-webrtc/src/auto/web_rtcice_transport.rs b/gstreamer-webrtc/src/auto/web_rtcice_transport.rs
index 79284c1f9..cb4f6162d 100644
--- a/gstreamer-webrtc/src/auto/web_rtcice_transport.rs
+++ b/gstreamer-webrtc/src/auto/web_rtcice_transport.rs
@@ -78,33 +78,33 @@ impl WebRTCICETransport {
 
     pub fn connect_on_new_candidate<F: Fn(&WebRTCICETransport, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCICETransport, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"on-new-candidate\0".as_ptr() as *const _,
-                transmute(on_new_candidate_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(on_new_candidate_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_on_selected_candidate_pair_change<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCICETransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"on-selected-candidate-pair-change\0".as_ptr() as *const _,
-                transmute(on_selected_candidate_pair_change_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(on_selected_candidate_pair_change_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_gathering_state_notify<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCICETransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::gathering-state\0".as_ptr() as *const _,
-                transmute(notify_gathering_state_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_gathering_state_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_state_notify<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&WebRTCICETransport) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::state\0".as_ptr() as *const _,
-                transmute(notify_state_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_state_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -112,22 +112,22 @@ impl WebRTCICETransport {
 unsafe impl Send for WebRTCICETransport {}
 unsafe impl Sync for WebRTCICETransport {}
 
-unsafe extern "C" fn on_new_candidate_trampoline(this: *mut ffi::GstWebRTCICETransport, object: *mut libc::c_char, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCICETransport, &str) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn on_new_candidate_trampoline<F: Fn(&WebRTCICETransport, &str) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCICETransport, object: *mut libc::c_char, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &GString::from_glib_borrow(object))
 }
 
-unsafe extern "C" fn on_selected_candidate_pair_change_trampoline(this: *mut ffi::GstWebRTCICETransport, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCICETransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn on_selected_candidate_pair_change_trampoline<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCICETransport, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_gathering_state_trampoline(this: *mut ffi::GstWebRTCICETransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCICETransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_gathering_state_trampoline<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCICETransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_state_trampoline(this: *mut ffi::GstWebRTCICETransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&WebRTCICETransport) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_state_trampoline<F: Fn(&WebRTCICETransport) + Send + Sync + 'static>(this: *mut ffi::GstWebRTCICETransport, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer/src/auto/bin.rs b/gstreamer/src/auto/bin.rs
index b8d02d030..3f80bdd7a 100644
--- a/gstreamer/src/auto/bin.rs
+++ b/gstreamer/src/auto/bin.rs
@@ -234,88 +234,88 @@ impl<O: IsA<Bin>> GstBinExt for O {
     #[cfg(any(feature = "v1_10", feature = "dox"))]
     fn connect_deep_element_added<F: Fn(&Self, &Bin, &Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Bin, &Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"deep-element-added\0".as_ptr() as *const _,
-                transmute(deep_element_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(deep_element_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     #[cfg(any(feature = "v1_10", feature = "dox"))]
     fn connect_deep_element_removed<F: Fn(&Self, &Bin, &Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Bin, &Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"deep-element-removed\0".as_ptr() as *const _,
-                transmute(deep_element_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(deep_element_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_element_added<F: Fn(&Self, &Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"element-added\0".as_ptr() as *const _,
-                transmute(element_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(element_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_element_removed<F: Fn(&Self, &Element) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Element) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"element-removed\0".as_ptr() as *const _,
-                transmute(element_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(element_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_async_handling_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::async-handling\0".as_ptr() as *const _,
-                transmute(notify_async_handling_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_async_handling_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_message_forward_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::message-forward\0".as_ptr() as *const _,
-                transmute(notify_message_forward_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_message_forward_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
 #[cfg(any(feature = "v1_10", feature = "dox"))]
-unsafe extern "C" fn deep_element_added_trampoline<P>(this: *mut ffi::GstBin, sub_bin: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn deep_element_added_trampoline<P, F: Fn(&P, &Bin, &Element) + Send + Sync + 'static>(this: *mut ffi::GstBin, sub_bin: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P, &Bin, &Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(sub_bin), &from_glib_borrow(element))
 }
 
 #[cfg(any(feature = "v1_10", feature = "dox"))]
-unsafe extern "C" fn deep_element_removed_trampoline<P>(this: *mut ffi::GstBin, sub_bin: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn deep_element_removed_trampoline<P, F: Fn(&P, &Bin, &Element) + Send + Sync + 'static>(this: *mut ffi::GstBin, sub_bin: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P, &Bin, &Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(sub_bin), &from_glib_borrow(element))
 }
 
-unsafe extern "C" fn element_added_trampoline<P>(this: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn element_added_trampoline<P, F: Fn(&P, &Element) + Send + Sync + 'static>(this: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P, &Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(element))
 }
 
-unsafe extern "C" fn element_removed_trampoline<P>(this: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn element_removed_trampoline<P, F: Fn(&P, &Element) + Send + Sync + 'static>(this: *mut ffi::GstBin, element: *mut ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P, &Element) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(element))
 }
 
-unsafe extern "C" fn notify_async_handling_trampoline<P>(this: *mut ffi::GstBin, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_async_handling_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBin, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_message_forward_trampoline<P>(this: *mut ffi::GstBin, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_message_forward_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstBin, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Bin> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Bin::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/bus.rs b/gstreamer/src/auto/bus.rs
index 31dffe293..ada609423 100644
--- a/gstreamer/src/auto/bus.rs
+++ b/gstreamer/src/auto/bus.rs
@@ -37,15 +37,7 @@ impl Bus {
         }
     }
 
-    //pub fn add_watch<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/BusFunc, user_data: P) -> u32 {
-    //    unsafe { TODO: call ffi::gst_bus_add_watch() }
-    //}
-
-    //pub fn add_watch_full(&self, priority: i32, func: /*Unknown conversion*//*Unimplemented*/BusFunc, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> u32 {
-    //    unsafe { TODO: call ffi::gst_bus_add_watch_full() }
-    //}
-
-    //pub fn async_signal_func<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, message: &Message, data: P) -> bool {
+    //pub fn async_signal_func(&self, message: &Message, data: /*Unimplemented*/Option<Fundamental: Pointer>) -> bool {
     //    unsafe { TODO: call ffi::gst_bus_async_signal_func() }
     //}
 
@@ -108,11 +100,7 @@ impl Bus {
         }
     }
 
-    //pub fn set_sync_handler<'a, P: Into<Option<&'a /*Unimplemented*/BusSyncHandler>>>(&self, func: P, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_bus_set_sync_handler() }
-    //}
-
-    //pub fn sync_signal_handler<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, message: &Message, data: P) -> BusSyncReply {
+    //pub fn sync_signal_handler(&self, message: &Message, data: /*Unimplemented*/Option<Fundamental: Pointer>) -> BusSyncReply {
     //    unsafe { TODO: call ffi::gst_bus_sync_signal_handler() }
     //}
 
@@ -124,17 +112,17 @@ impl Bus {
 
     pub fn connect_message<F: Fn(&Bus, &Message) + Send + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Bus, &Message) + Send + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"message\0".as_ptr() as *const _,
-                transmute(message_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(message_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_sync_message<F: Fn(&Bus, &Message) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Bus, &Message) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"sync-message\0".as_ptr() as *const _,
-                transmute(sync_message_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(sync_message_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -148,12 +136,12 @@ impl Default for Bus {
 unsafe impl Send for Bus {}
 unsafe impl Sync for Bus {}
 
-unsafe extern "C" fn message_trampoline(this: *mut ffi::GstBus, message: *mut ffi::GstMessage, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Bus, &Message) + Send + 'static) = transmute(f);
+unsafe extern "C" fn message_trampoline<F: Fn(&Bus, &Message) + Send + 'static>(this: *mut ffi::GstBus, message: *mut ffi::GstMessage, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(message))
 }
 
-unsafe extern "C" fn sync_message_trampoline(this: *mut ffi::GstBus, message: *mut ffi::GstMessage, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Bus, &Message) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn sync_message_trampoline<F: Fn(&Bus, &Message) + Send + Sync + 'static>(this: *mut ffi::GstBus, message: *mut ffi::GstMessage, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(message))
 }
diff --git a/gstreamer/src/auto/child_proxy.rs b/gstreamer/src/auto/child_proxy.rs
index 4eb36565b..f82cae1ee 100644
--- a/gstreamer/src/auto/child_proxy.rs
+++ b/gstreamer/src/auto/child_proxy.rs
@@ -120,29 +120,29 @@ impl<O: IsA<ChildProxy>> ChildProxyExt for O {
 
     fn connect_child_added<F: Fn(&Self, &glib::Object, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &glib::Object, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"child-added\0".as_ptr() as *const _,
-                transmute(child_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(child_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_child_removed<F: Fn(&Self, &glib::Object, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &glib::Object, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"child-removed\0".as_ptr() as *const _,
-                transmute(child_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(child_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn child_added_trampoline<P>(this: *mut ffi::GstChildProxy, object: *mut gobject_ffi::GObject, name: *mut libc::c_char, f: glib_ffi::gpointer)
+unsafe extern "C" fn child_added_trampoline<P, F: Fn(&P, &glib::Object, &str) + Send + Sync + 'static>(this: *mut ffi::GstChildProxy, object: *mut gobject_ffi::GObject, name: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<ChildProxy> {
-    let f: &&(Fn(&P, &glib::Object, &str) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&ChildProxy::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object), &GString::from_glib_borrow(name))
 }
 
-unsafe extern "C" fn child_removed_trampoline<P>(this: *mut ffi::GstChildProxy, object: *mut gobject_ffi::GObject, name: *mut libc::c_char, f: glib_ffi::gpointer)
+unsafe extern "C" fn child_removed_trampoline<P, F: Fn(&P, &glib::Object, &str) + Send + Sync + 'static>(this: *mut ffi::GstChildProxy, object: *mut gobject_ffi::GObject, name: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<ChildProxy> {
-    let f: &&(Fn(&P, &glib::Object, &str) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&ChildProxy::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(object), &GString::from_glib_borrow(name))
 }
diff --git a/gstreamer/src/auto/clock.rs b/gstreamer/src/auto/clock.rs
index d84d83037..34e6a86a0 100644
--- a/gstreamer/src/auto/clock.rs
+++ b/gstreamer/src/auto/clock.rs
@@ -28,7 +28,7 @@ glib_wrapper! {
 }
 
 impl Clock {
-    //pub fn id_compare_func<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>, Q: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(id1: P, id2: Q) -> i32 {
+    //pub fn id_compare_func(id1: /*Unimplemented*/Option<Fundamental: Pointer>, id2: /*Unimplemented*/Option<Fundamental: Pointer>) -> i32 {
     //    unsafe { TODO: call ffi::gst_clock_id_compare_func() }
     //}
 
@@ -52,7 +52,7 @@ impl Clock {
     //    unsafe { TODO: call ffi::gst_clock_id_wait() }
     //}
 
-    //pub fn id_wait_async(id: /*Unimplemented*/ClockID, func: /*Unknown conversion*//*Unimplemented*/ClockCallback, destroy_data: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> ClockReturn {
+    //pub fn id_wait_async(id: /*Unimplemented*/ClockID, func: /*Unimplemented*/Fn(&Clock, ClockTime, /*Unimplemented*/ClockID) -> bool, user_data: /*Unimplemented*/Option<Fundamental: Pointer>) -> ClockReturn {
     //    unsafe { TODO: call ffi::gst_clock_id_wait_async() }
     //}
 }
@@ -285,57 +285,57 @@ impl<O: IsA<Clock>> ClockExt for O {
 
     fn connect_synced<F: Fn(&Self, bool) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, bool) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"synced\0".as_ptr() as *const _,
-                transmute(synced_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(synced_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_timeout_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::timeout\0".as_ptr() as *const _,
-                transmute(notify_timeout_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_timeout_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_window_size_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::window-size\0".as_ptr() as *const _,
-                transmute(notify_window_size_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_window_size_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_window_threshold_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::window-threshold\0".as_ptr() as *const _,
-                transmute(notify_window_threshold_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_window_threshold_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn synced_trampoline<P>(this: *mut ffi::GstClock, synced: glib_ffi::gboolean, f: glib_ffi::gpointer)
+unsafe extern "C" fn synced_trampoline<P, F: Fn(&P, bool) + Send + Sync + 'static>(this: *mut ffi::GstClock, synced: glib_ffi::gboolean, f: glib_ffi::gpointer)
 where P: IsA<Clock> {
-    let f: &&(Fn(&P, bool) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clock::from_glib_borrow(this).unsafe_cast(), from_glib(synced))
 }
 
-unsafe extern "C" fn notify_timeout_trampoline<P>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_timeout_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Clock> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clock::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_window_size_trampoline<P>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_window_size_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Clock> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clock::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_window_threshold_trampoline<P>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_window_threshold_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Clock> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Clock::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/date_time.rs b/gstreamer/src/auto/date_time.rs
index af6f05a79..f9d54c07c 100644
--- a/gstreamer/src/auto/date_time.rs
+++ b/gstreamer/src/auto/date_time.rs
@@ -26,14 +26,14 @@ impl DateTime {
         }
     }
 
-    pub fn new_from_g_date_time(dt: &glib::DateTime) -> DateTime {
+    pub fn new_from_g_date_time(dt: &glib::DateTime) -> Option<DateTime> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gst_date_time_new_from_g_date_time(dt.to_glib_full()))
         }
     }
 
-    pub fn new_from_iso8601_string(string: &str) -> DateTime {
+    pub fn new_from_iso8601_string(string: &str) -> Option<DateTime> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gst_date_time_new_from_iso8601_string(string.to_glib_none().0))
diff --git a/gstreamer/src/auto/device.rs b/gstreamer/src/auto/device.rs
index 7073b2712..bbd479b45 100644
--- a/gstreamer/src/auto/device.rs
+++ b/gstreamer/src/auto/device.rs
@@ -103,15 +103,15 @@ impl<O: IsA<Device>> DeviceExt for O {
 
     fn connect_removed<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"removed\0".as_ptr() as *const _,
-                transmute(removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn removed_trampoline<P>(this: *mut ffi::GstDevice, f: glib_ffi::gpointer)
+unsafe extern "C" fn removed_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstDevice, f: glib_ffi::gpointer)
 where P: IsA<Device> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Device::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/device_monitor.rs b/gstreamer/src/auto/device_monitor.rs
index 3fbd365fd..05685c8d8 100644
--- a/gstreamer/src/auto/device_monitor.rs
+++ b/gstreamer/src/auto/device_monitor.rs
@@ -114,15 +114,15 @@ impl<O: IsA<DeviceMonitor>> DeviceMonitorExt for O {
 
     fn connect_property_show_all_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::show-all\0".as_ptr() as *const _,
-                transmute(notify_show_all_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_show_all_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_show_all_trampoline<P>(this: *mut ffi::GstDeviceMonitor, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_show_all_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstDeviceMonitor, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<DeviceMonitor> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&DeviceMonitor::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/device_provider.rs b/gstreamer/src/auto/device_provider.rs
index 5006e8cf1..41bd2cd43 100644
--- a/gstreamer/src/auto/device_provider.rs
+++ b/gstreamer/src/auto/device_provider.rs
@@ -140,29 +140,29 @@ impl<O: IsA<DeviceProvider>> DeviceProviderExt for O {
 
     fn connect_provider_hidden<F: Fn(&Self, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"provider-hidden\0".as_ptr() as *const _,
-                transmute(provider_hidden_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(provider_hidden_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_provider_unhidden<F: Fn(&Self, &str) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &str) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"provider-unhidden\0".as_ptr() as *const _,
-                transmute(provider_unhidden_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(provider_unhidden_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn provider_hidden_trampoline<P>(this: *mut ffi::GstDeviceProvider, object: *mut libc::c_char, f: glib_ffi::gpointer)
+unsafe extern "C" fn provider_hidden_trampoline<P, F: Fn(&P, &str) + Send + Sync + 'static>(this: *mut ffi::GstDeviceProvider, object: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<DeviceProvider> {
-    let f: &&(Fn(&P, &str) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&DeviceProvider::from_glib_borrow(this).unsafe_cast(), &GString::from_glib_borrow(object))
 }
 
-unsafe extern "C" fn provider_unhidden_trampoline<P>(this: *mut ffi::GstDeviceProvider, object: *mut libc::c_char, f: glib_ffi::gpointer)
+unsafe extern "C" fn provider_unhidden_trampoline<P, F: Fn(&P, &str) + Send + Sync + 'static>(this: *mut ffi::GstDeviceProvider, object: *mut libc::c_char, f: glib_ffi::gpointer)
 where P: IsA<DeviceProvider> {
-    let f: &&(Fn(&P, &str) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&DeviceProvider::from_glib_borrow(this).unsafe_cast(), &GString::from_glib_borrow(object))
 }
diff --git a/gstreamer/src/auto/element.rs b/gstreamer/src/auto/element.rs
index 098821e98..9c848343c 100644
--- a/gstreamer/src/auto/element.rs
+++ b/gstreamer/src/auto/element.rs
@@ -66,19 +66,16 @@ pub trait ElementExt: 'static {
 
     fn add_pad<P: IsA<Pad>>(&self, pad: &P) -> Result<(), glib::error::BoolError>;
 
-    //#[cfg(any(feature = "v1_10", feature = "dox"))]
-    //fn call_async(&self, func: /*Unknown conversion*//*Unimplemented*/ElementCallAsyncFunc, destroy_notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
     fn create_all_pads(&self);
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool;
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool;
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_sink_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool;
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_sink_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool;
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_src_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool;
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_src_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool;
 
     fn get_base_time(&self) -> ClockTime;
 
@@ -181,31 +178,62 @@ impl<O: IsA<Element>> ElementExt for O {
         }
     }
 
-    //#[cfg(any(feature = "v1_10", feature = "dox"))]
-    //fn call_async(&self, func: /*Unknown conversion*//*Unimplemented*/ElementCallAsyncFunc, destroy_notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_element_call_async() }
-    //}
-
     fn create_all_pads(&self) {
         unsafe {
             ffi::gst_element_create_all_pads(self.as_ref().to_glib_none().0);
         }
     }
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool {
-    //    unsafe { TODO: call ffi::gst_element_foreach_pad() }
-    //}
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool {
+        let func_data: P = func;
+        unsafe extern "C" fn func_func<P: FnMut(&Element, &Pad) -> bool>(element: *mut ffi::GstElement, pad: *mut ffi::GstPad, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let element = from_glib_borrow(element);
+            let pad = from_glib_borrow(pad);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&element, &pad);
+            res.to_glib()
+        }
+        let func = Some(func_func::<P> as _);
+        let super_callback0: &P = &func_data;
+        unsafe {
+            from_glib(ffi::gst_element_foreach_pad(self.as_ref().to_glib_none().0, func, super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_sink_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool {
-    //    unsafe { TODO: call ffi::gst_element_foreach_sink_pad() }
-    //}
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_sink_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool {
+        let func_data: P = func;
+        unsafe extern "C" fn func_func<P: FnMut(&Element, &Pad) -> bool>(element: *mut ffi::GstElement, pad: *mut ffi::GstPad, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let element = from_glib_borrow(element);
+            let pad = from_glib_borrow(pad);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&element, &pad);
+            res.to_glib()
+        }
+        let func = Some(func_func::<P> as _);
+        let super_callback0: &P = &func_data;
+        unsafe {
+            from_glib(ffi::gst_element_foreach_sink_pad(self.as_ref().to_glib_none().0, func, super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
-    //#[cfg(any(feature = "v1_14", feature = "dox"))]
-    //fn foreach_src_pad<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, func: /*Unknown conversion*//*Unimplemented*/ElementForeachPadFunc, user_data: P) -> bool {
-    //    unsafe { TODO: call ffi::gst_element_foreach_src_pad() }
-    //}
+    #[cfg(any(feature = "v1_14", feature = "dox"))]
+    fn foreach_src_pad<P: FnMut(&Element, &Pad) -> bool>(&self, func: P) -> bool {
+        let func_data: P = func;
+        unsafe extern "C" fn func_func<P: FnMut(&Element, &Pad) -> bool>(element: *mut ffi::GstElement, pad: *mut ffi::GstPad, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let element = from_glib_borrow(element);
+            let pad = from_glib_borrow(pad);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&element, &pad);
+            res.to_glib()
+        }
+        let func = Some(func_func::<P> as _);
+        let super_callback0: &P = &func_data;
+        unsafe {
+            from_glib(ffi::gst_element_foreach_src_pad(self.as_ref().to_glib_none().0, func, super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
     fn get_base_time(&self) -> ClockTime {
         unsafe {
@@ -449,43 +477,43 @@ impl<O: IsA<Element>> ElementExt for O {
 
     fn connect_no_more_pads<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"no-more-pads\0".as_ptr() as *const _,
-                transmute(no_more_pads_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(no_more_pads_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_pad_added<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Pad) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pad-added\0".as_ptr() as *const _,
-                transmute(pad_added_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pad_added_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_pad_removed<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Pad) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pad-removed\0".as_ptr() as *const _,
-                transmute(pad_removed_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pad_removed_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn no_more_pads_trampoline<P>(this: *mut ffi::GstElement, f: glib_ffi::gpointer)
+unsafe extern "C" fn no_more_pads_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstElement, f: glib_ffi::gpointer)
 where P: IsA<Element> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Element::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn pad_added_trampoline<P>(this: *mut ffi::GstElement, new_pad: *mut ffi::GstPad, f: glib_ffi::gpointer)
+unsafe extern "C" fn pad_added_trampoline<P, F: Fn(&P, &Pad) + Send + Sync + 'static>(this: *mut ffi::GstElement, new_pad: *mut ffi::GstPad, f: glib_ffi::gpointer)
 where P: IsA<Element> {
-    let f: &&(Fn(&P, &Pad) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Element::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(new_pad))
 }
 
-unsafe extern "C" fn pad_removed_trampoline<P>(this: *mut ffi::GstElement, old_pad: *mut ffi::GstPad, f: glib_ffi::gpointer)
+unsafe extern "C" fn pad_removed_trampoline<P, F: Fn(&P, &Pad) + Send + Sync + 'static>(this: *mut ffi::GstElement, old_pad: *mut ffi::GstPad, f: glib_ffi::gpointer)
 where P: IsA<Element> {
-    let f: &&(Fn(&P, &Pad) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Element::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(old_pad))
 }
diff --git a/gstreamer/src/auto/ghost_pad.rs b/gstreamer/src/auto/ghost_pad.rs
index 13612b84a..854c6e604 100644
--- a/gstreamer/src/auto/ghost_pad.rs
+++ b/gstreamer/src/auto/ghost_pad.rs
@@ -22,19 +22,19 @@ glib_wrapper! {
 }
 
 impl GhostPad {
-    pub fn new_no_target<'a, P: Into<Option<&'a str>>>(name: P, dir: PadDirection) -> GhostPad {
+    pub fn new_no_target<'a, P: Into<Option<&'a str>>>(name: P, dir: PadDirection) -> Option<GhostPad> {
         assert_initialized_main_thread!();
         let name = name.into();
         unsafe {
-            Pad::from_glib_none(ffi::gst_ghost_pad_new_no_target(name.to_glib_none().0, dir.to_glib())).unsafe_cast()
+            Option::<Pad>::from_glib_none(ffi::gst_ghost_pad_new_no_target(name.to_glib_none().0, dir.to_glib())).map(|o| o.unsafe_cast())
         }
     }
 
-    pub fn new_no_target_from_template<'a, P: Into<Option<&'a str>>>(name: P, templ: &PadTemplate) -> GhostPad {
+    pub fn new_no_target_from_template<'a, P: Into<Option<&'a str>>>(name: P, templ: &PadTemplate) -> Option<GhostPad> {
         skip_assert_initialized!();
         let name = name.into();
         unsafe {
-            Pad::from_glib_none(ffi::gst_ghost_pad_new_no_target_from_template(name.to_glib_none().0, templ.to_glib_none().0)).unsafe_cast()
+            Option::<Pad>::from_glib_none(ffi::gst_ghost_pad_new_no_target_from_template(name.to_glib_none().0, templ.to_glib_none().0)).map(|o| o.unsafe_cast())
         }
     }
 }
diff --git a/gstreamer/src/auto/object.rs b/gstreamer/src/auto/object.rs
index d7713fe02..bf4cb58b6 100644
--- a/gstreamer/src/auto/object.rs
+++ b/gstreamer/src/auto/object.rs
@@ -32,11 +32,11 @@ impl Object {
         }
     }
 
-    //pub fn default_deep_notify<P: IsA<glib::Object>, Q: IsA<Object>, R: IsA</*Ignored*/glib::ParamSpec>>(object: &P, orig: &Q, pspec: &R, excluded_props: &[&str]) {
+    //pub fn default_deep_notify<P: IsA<glib::Object>, Q: IsA<Object>>(object: &P, orig: &Q, pspec: /*Ignored*/&glib::ParamSpec, excluded_props: &[&str]) {
     //    unsafe { TODO: call ffi::gst_object_default_deep_notify() }
     //}
 
-    //pub fn ref_sink<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(object: P) -> /*Unimplemented*/Option<Fundamental: Pointer> {
+    //pub fn ref_sink(object: /*Unimplemented*/Option<Fundamental: Pointer>) -> /*Unimplemented*/Option<Fundamental: Pointer> {
     //    unsafe { TODO: call ffi::gst_object_ref_sink() }
     //}
 
@@ -51,7 +51,7 @@ unsafe impl Sync for Object {}
 pub const NONE_OBJECT: Option<&Object> = None;
 
 pub trait GstObjectExt: 'static {
-    //fn add_control_binding<P: IsA</*Ignored*/ControlBinding>>(&self, binding: &P) -> bool;
+    //fn add_control_binding(&self, binding: /*Ignored*/&ControlBinding) -> bool;
 
     fn default_error<'a, P: Into<Option<&'a str>>>(&self, error: &Error, debug: P);
 
@@ -69,7 +69,7 @@ pub trait GstObjectExt: 'static {
 
     //fn get_value(&self, property_name: &str, timestamp: ClockTime) -> /*Ignored*/Option<glib::Value>;
 
-    //fn get_value_array<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, property_name: &str, timestamp: ClockTime, interval: ClockTime, n_values: u32, values: P) -> bool;
+    //fn get_value_array(&self, property_name: &str, timestamp: ClockTime, interval: ClockTime, n_values: u32, values: /*Unimplemented*/Option<Fundamental: Pointer>) -> bool;
 
     fn has_active_control_bindings(&self) -> bool;
 
@@ -79,7 +79,7 @@ pub trait GstObjectExt: 'static {
 
     fn has_as_parent<P: IsA<Object>>(&self, parent: &P) -> bool;
 
-    //fn remove_control_binding<P: IsA</*Ignored*/ControlBinding>>(&self, binding: &P) -> bool;
+    //fn remove_control_binding(&self, binding: /*Ignored*/&ControlBinding) -> bool;
 
     fn set_control_binding_disabled(&self, property_name: &str, disabled: bool);
 
@@ -105,7 +105,7 @@ pub trait GstObjectExt: 'static {
 }
 
 impl<O: IsA<Object>> GstObjectExt for O {
-    //fn add_control_binding<P: IsA</*Ignored*/ControlBinding>>(&self, binding: &P) -> bool {
+    //fn add_control_binding(&self, binding: /*Ignored*/&ControlBinding) -> bool {
     //    unsafe { TODO: call ffi::gst_object_add_control_binding() }
     //}
 
@@ -152,7 +152,7 @@ impl<O: IsA<Object>> GstObjectExt for O {
     //    unsafe { TODO: call ffi::gst_object_get_value() }
     //}
 
-    //fn get_value_array<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, property_name: &str, timestamp: ClockTime, interval: ClockTime, n_values: u32, values: P) -> bool {
+    //fn get_value_array(&self, property_name: &str, timestamp: ClockTime, interval: ClockTime, n_values: u32, values: /*Unimplemented*/Option<Fundamental: Pointer>) -> bool {
     //    unsafe { TODO: call ffi::gst_object_get_value_array() }
     //}
 
@@ -180,7 +180,7 @@ impl<O: IsA<Object>> GstObjectExt for O {
         }
     }
 
-    //fn remove_control_binding<P: IsA</*Ignored*/ControlBinding>>(&self, binding: &P) -> bool {
+    //fn remove_control_binding(&self, binding: /*Ignored*/&ControlBinding) -> bool {
     //    unsafe { TODO: call ffi::gst_object_remove_control_binding() }
     //}
 
@@ -238,29 +238,29 @@ impl<O: IsA<Object>> GstObjectExt for O {
 
     fn connect_property_name_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::name\0".as_ptr() as *const _,
-                transmute(notify_name_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_name_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_parent_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::parent\0".as_ptr() as *const _,
-                transmute(notify_parent_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_parent_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_name_trampoline<P>(this: *mut ffi::GstObject, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_name_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstObject, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Object> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Object::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_parent_trampoline<P>(this: *mut ffi::GstObject, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_parent_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstObject, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Object> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Object::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/pad.rs b/gstreamer/src/auto/pad.rs
index e65065793..aa61bf032 100644
--- a/gstreamer/src/auto/pad.rs
+++ b/gstreamer/src/auto/pad.rs
@@ -65,8 +65,6 @@ pub const NONE_PAD: Option<&Pad> = None;
 pub trait PadExt: 'static {
     fn activate_mode(&self, mode: PadMode, active: bool) -> Result<(), glib::error::BoolError>;
 
-    //fn add_probe(&self, mask: PadProbeType, callback: /*Unknown conversion*//*Unimplemented*/PadProbeCallback, destroy_data: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> libc::c_ulong;
-
     fn can_link<P: IsA<Pad>>(&self, sinkpad: &P) -> bool;
 
     fn check_reconfigure(&self) -> bool;
@@ -77,7 +75,7 @@ pub trait PadExt: 'static {
 
     //fn create_stream_id_printf_valist<'a, P: IsA<Element>, Q: Into<Option<&'a str>>>(&self, parent: &P, stream_id: Q, var_args: /*Unknown conversion*//*Unimplemented*/Unsupported) -> Option<GString>;
 
-    //fn forward<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, forward: /*Unknown conversion*//*Unimplemented*/PadForwardFunction, user_data: P) -> bool;
+    fn forward<P: FnMut(&Pad) -> bool>(&self, forward: P) -> bool;
 
     fn get_allowed_caps(&self) -> Option<Caps>;
 
@@ -141,38 +139,12 @@ pub trait PadExt: 'static {
 
     fn query_caps<'a, P: Into<Option<&'a Caps>>>(&self, filter: P) -> Option<Caps>;
 
-    //fn set_activate_function_full(&self, activate: /*Unknown conversion*//*Unimplemented*/PadActivateFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_activatemode_function_full(&self, activatemode: /*Unknown conversion*//*Unimplemented*/PadActivateModeFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
     fn set_active(&self, active: bool) -> Result<(), glib::error::BoolError>;
 
-    //fn set_chain_function_full(&self, chain: /*Unknown conversion*//*Unimplemented*/PadChainFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_chain_list_function_full(&self, chainlist: /*Unknown conversion*//*Unimplemented*/PadChainListFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_element_private<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, priv_: P);
-
-    //fn set_event_full_function_full(&self, event: /*Unknown conversion*//*Unimplemented*/PadEventFullFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_event_function_full(&self, event: /*Unknown conversion*//*Unimplemented*/PadEventFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_getrange_function_full(&self, get: /*Unknown conversion*//*Unimplemented*/PadGetRangeFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_iterate_internal_links_function_full(&self, iterintlink: /*Unknown conversion*//*Unimplemented*/PadIterIntLinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_link_function_full(&self, link: /*Unknown conversion*//*Unimplemented*/PadLinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
+    //fn set_element_private(&self, priv_: /*Unimplemented*/Option<Fundamental: Pointer>);
 
     fn set_offset(&self, offset: i64);
 
-    //fn set_query_function_full(&self, query: /*Unknown conversion*//*Unimplemented*/PadQueryFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn set_unlink_function_full(&self, unlink: /*Unknown conversion*//*Unimplemented*/PadUnlinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify);
-
-    //fn start_task(&self, func: /*Unknown conversion*//*Unimplemented*/TaskFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> bool;
-
-    //fn sticky_events_foreach<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, foreach_func: /*Unknown conversion*//*Unimplemented*/PadStickyEventsForeachFunction, user_data: P);
-
     fn stop_task(&self) -> Result<(), glib::error::BoolError>;
 
     fn unlink<P: IsA<Pad>>(&self, sinkpad: &P) -> Result<(), glib::error::BoolError>;
@@ -203,10 +175,6 @@ impl<O: IsA<Pad>> PadExt for O {
         }
     }
 
-    //fn add_probe(&self, mask: PadProbeType, callback: /*Unknown conversion*//*Unimplemented*/PadProbeCallback, destroy_data: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> libc::c_ulong {
-    //    unsafe { TODO: call ffi::gst_pad_add_probe() }
-    //}
-
     fn can_link<P: IsA<Pad>>(&self, sinkpad: &P) -> bool {
         unsafe {
             from_glib(ffi::gst_pad_can_link(self.as_ref().to_glib_none().0, sinkpad.as_ref().to_glib_none().0))
@@ -234,9 +202,20 @@ impl<O: IsA<Pad>> PadExt for O {
     //    unsafe { TODO: call ffi::gst_pad_create_stream_id_printf_valist() }
     //}
 
-    //fn forward<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, forward: /*Unknown conversion*//*Unimplemented*/PadForwardFunction, user_data: P) -> bool {
-    //    unsafe { TODO: call ffi::gst_pad_forward() }
-    //}
+    fn forward<P: FnMut(&Pad) -> bool>(&self, forward: P) -> bool {
+        let forward_data: P = forward;
+        unsafe extern "C" fn forward_func<P: FnMut(&Pad) -> bool>(pad: *mut ffi::GstPad, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let pad = from_glib_borrow(pad);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&pad);
+            res.to_glib()
+        }
+        let forward = Some(forward_func::<P> as _);
+        let super_callback0: &P = &forward_data;
+        unsafe {
+            from_glib(ffi::gst_pad_forward(self.as_ref().to_glib_none().0, forward, super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
     fn get_allowed_caps(&self) -> Option<Caps> {
         unsafe {
@@ -412,74 +391,22 @@ impl<O: IsA<Pad>> PadExt for O {
         }
     }
 
-    //fn set_activate_function_full(&self, activate: /*Unknown conversion*//*Unimplemented*/PadActivateFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_activate_function_full() }
-    //}
-
-    //fn set_activatemode_function_full(&self, activatemode: /*Unknown conversion*//*Unimplemented*/PadActivateModeFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_activatemode_function_full() }
-    //}
-
     fn set_active(&self, active: bool) -> Result<(), glib::error::BoolError> {
         unsafe {
             glib_result_from_gboolean!(ffi::gst_pad_set_active(self.as_ref().to_glib_none().0, active.to_glib()), "Failed to activate pad")
         }
     }
 
-    //fn set_chain_function_full(&self, chain: /*Unknown conversion*//*Unimplemented*/PadChainFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_chain_function_full() }
-    //}
-
-    //fn set_chain_list_function_full(&self, chainlist: /*Unknown conversion*//*Unimplemented*/PadChainListFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_chain_list_function_full() }
-    //}
-
-    //fn set_element_private<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, priv_: P) {
+    //fn set_element_private(&self, priv_: /*Unimplemented*/Option<Fundamental: Pointer>) {
     //    unsafe { TODO: call ffi::gst_pad_set_element_private() }
     //}
 
-    //fn set_event_full_function_full(&self, event: /*Unknown conversion*//*Unimplemented*/PadEventFullFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_event_full_function_full() }
-    //}
-
-    //fn set_event_function_full(&self, event: /*Unknown conversion*//*Unimplemented*/PadEventFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_event_function_full() }
-    //}
-
-    //fn set_getrange_function_full(&self, get: /*Unknown conversion*//*Unimplemented*/PadGetRangeFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_getrange_function_full() }
-    //}
-
-    //fn set_iterate_internal_links_function_full(&self, iterintlink: /*Unknown conversion*//*Unimplemented*/PadIterIntLinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_iterate_internal_links_function_full() }
-    //}
-
-    //fn set_link_function_full(&self, link: /*Unknown conversion*//*Unimplemented*/PadLinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_link_function_full() }
-    //}
-
     fn set_offset(&self, offset: i64) {
         unsafe {
             ffi::gst_pad_set_offset(self.as_ref().to_glib_none().0, offset);
         }
     }
 
-    //fn set_query_function_full(&self, query: /*Unknown conversion*//*Unimplemented*/PadQueryFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_query_function_full() }
-    //}
-
-    //fn set_unlink_function_full(&self, unlink: /*Unknown conversion*//*Unimplemented*/PadUnlinkFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) {
-    //    unsafe { TODO: call ffi::gst_pad_set_unlink_function_full() }
-    //}
-
-    //fn start_task(&self, func: /*Unknown conversion*//*Unimplemented*/TaskFunction, notify: /*Unknown conversion*//*Unimplemented*/DestroyNotify) -> bool {
-    //    unsafe { TODO: call ffi::gst_pad_start_task() }
-    //}
-
-    //fn sticky_events_foreach<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, foreach_func: /*Unknown conversion*//*Unimplemented*/PadStickyEventsForeachFunction, user_data: P) {
-    //    unsafe { TODO: call ffi::gst_pad_sticky_events_foreach() }
-    //}
-
     fn stop_task(&self) -> Result<(), glib::error::BoolError> {
         unsafe {
             glib_result_from_gboolean!(ffi::gst_pad_stop_task(self.as_ref().to_glib_none().0), "Failed to stop pad task")
@@ -522,71 +449,71 @@ impl<O: IsA<Pad>> PadExt for O {
 
     fn connect_linked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Pad) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"linked\0".as_ptr() as *const _,
-                transmute(linked_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(linked_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_unlinked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self, &Pad) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"unlinked\0".as_ptr() as *const _,
-                transmute(unlinked_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(unlinked_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_caps_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::caps\0".as_ptr() as *const _,
-                transmute(notify_caps_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_caps_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_offset_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::offset\0".as_ptr() as *const _,
-                transmute(notify_offset_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_offset_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_template_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::template\0".as_ptr() as *const _,
-                transmute(notify_template_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_template_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn linked_trampoline<P>(this: *mut ffi::GstPad, peer: *mut ffi::GstPad, f: glib_ffi::gpointer)
+unsafe extern "C" fn linked_trampoline<P, F: Fn(&P, &Pad) + Send + Sync + 'static>(this: *mut ffi::GstPad, peer: *mut ffi::GstPad, f: glib_ffi::gpointer)
 where P: IsA<Pad> {
-    let f: &&(Fn(&P, &Pad) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pad::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(peer))
 }
 
-unsafe extern "C" fn unlinked_trampoline<P>(this: *mut ffi::GstPad, peer: *mut ffi::GstPad, f: glib_ffi::gpointer)
+unsafe extern "C" fn unlinked_trampoline<P, F: Fn(&P, &Pad) + Send + Sync + 'static>(this: *mut ffi::GstPad, peer: *mut ffi::GstPad, f: glib_ffi::gpointer)
 where P: IsA<Pad> {
-    let f: &&(Fn(&P, &Pad) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pad::from_glib_borrow(this).unsafe_cast(), &from_glib_borrow(peer))
 }
 
-unsafe extern "C" fn notify_caps_trampoline<P>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_caps_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pad> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pad::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_offset_trampoline<P>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_offset_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pad> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pad::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_template_trampoline<P>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_template_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPad, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pad> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pad::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/pad_template.rs b/gstreamer/src/auto/pad_template.rs
index 3c2617639..a66454880 100644
--- a/gstreamer/src/auto/pad_template.rs
+++ b/gstreamer/src/auto/pad_template.rs
@@ -32,7 +32,7 @@ glib_wrapper! {
 }
 
 impl PadTemplate {
-    pub fn new(name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps) -> PadTemplate {
+    pub fn new(name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps) -> Option<PadTemplate> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_none(ffi::gst_pad_template_new(name_template.to_glib_none().0, direction.to_glib(), presence.to_glib(), caps.to_glib_none().0))
@@ -40,7 +40,7 @@ impl PadTemplate {
     }
 
     #[cfg(any(feature = "v1_14", feature = "dox"))]
-    pub fn new_with_gtype(name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps, pad_type: glib::types::Type) -> PadTemplate {
+    pub fn new_with_gtype(name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps, pad_type: glib::types::Type) -> Option<PadTemplate> {
         assert_initialized_main_thread!();
         unsafe {
             from_glib_none(ffi::gst_pad_template_new_with_gtype(name_template.to_glib_none().0, direction.to_glib(), presence.to_glib(), caps.to_glib_none().0, pad_type.to_glib()))
@@ -94,9 +94,9 @@ impl PadTemplate {
 
     pub fn connect_pad_created<F: Fn(&PadTemplate, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&PadTemplate, &Pad) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"pad-created\0".as_ptr() as *const _,
-                transmute(pad_created_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(pad_created_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -104,7 +104,7 @@ impl PadTemplate {
 unsafe impl Send for PadTemplate {}
 unsafe impl Sync for PadTemplate {}
 
-unsafe extern "C" fn pad_created_trampoline(this: *mut ffi::GstPadTemplate, pad: *mut ffi::GstPad, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&PadTemplate, &Pad) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn pad_created_trampoline<F: Fn(&PadTemplate, &Pad) + Send + Sync + 'static>(this: *mut ffi::GstPadTemplate, pad: *mut ffi::GstPad, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(pad))
 }
diff --git a/gstreamer/src/auto/pipeline.rs b/gstreamer/src/auto/pipeline.rs
index 1d89485b2..fb2afa99e 100644
--- a/gstreamer/src/auto/pipeline.rs
+++ b/gstreamer/src/auto/pipeline.rs
@@ -125,43 +125,43 @@ impl<O: IsA<Pipeline>> PipelineExt for O {
 
     fn connect_property_auto_flush_bus_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::auto-flush-bus\0".as_ptr() as *const _,
-                transmute(notify_auto_flush_bus_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_auto_flush_bus_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_delay_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::delay\0".as_ptr() as *const _,
-                transmute(notify_delay_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_delay_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 
     fn connect_property_latency_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::latency\0".as_ptr() as *const _,
-                transmute(notify_latency_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_latency_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_auto_flush_bus_trampoline<P>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_auto_flush_bus_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_delay_trampoline<P>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_delay_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
 
-unsafe extern "C" fn notify_latency_trampoline<P>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_latency_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstPipeline, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<Pipeline> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&Pipeline::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/plugin.rs b/gstreamer/src/auto/plugin.rs
index 571a616a7..15e7689c4 100644
--- a/gstreamer/src/auto/plugin.rs
+++ b/gstreamer/src/auto/plugin.rs
@@ -110,14 +110,6 @@ impl Plugin {
             if error.is_null() { Ok(from_glib_full(ret)) } else { Err(from_glib_full(error)) }
         }
     }
-
-    //pub fn register_static(major_version: i32, minor_version: i32, name: &str, description: &str, init_func: /*Unknown conversion*//*Unimplemented*/PluginInitFunc, version: &str, license: &str, source: &str, package: &str, origin: &str) -> bool {
-    //    unsafe { TODO: call ffi::gst_plugin_register_static() }
-    //}
-
-    //pub fn register_static_full<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(major_version: i32, minor_version: i32, name: &str, description: &str, init_full_func: /*Unknown conversion*//*Unimplemented*/PluginInitFullFunc, version: &str, license: &str, source: &str, package: &str, origin: &str, user_data: P) -> bool {
-    //    unsafe { TODO: call ffi::gst_plugin_register_static_full() }
-    //}
 }
 
 unsafe impl Send for Plugin {}
diff --git a/gstreamer/src/auto/registry.rs b/gstreamer/src/auto/registry.rs
index 7bbd58c48..d09b668bf 100644
--- a/gstreamer/src/auto/registry.rs
+++ b/gstreamer/src/auto/registry.rs
@@ -44,9 +44,20 @@ impl Registry {
         }
     }
 
-    //pub fn feature_filter<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, filter: /*Unknown conversion*//*Unimplemented*/PluginFeatureFilter, first: bool, user_data: P) -> Vec<PluginFeature> {
-    //    unsafe { TODO: call ffi::gst_registry_feature_filter() }
-    //}
+    pub fn feature_filter<P: FnMut(&PluginFeature) -> bool>(&self, filter: P, first: bool) -> Vec<PluginFeature> {
+        let filter_data: P = filter;
+        unsafe extern "C" fn filter_func<P: FnMut(&PluginFeature) -> bool>(feature: *mut ffi::GstPluginFeature, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let feature = from_glib_borrow(feature);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&feature);
+            res.to_glib()
+        }
+        let filter = Some(filter_func::<P> as _);
+        let super_callback0: &P = &filter_data;
+        unsafe {
+            FromGlibPtrContainer::from_glib_full(ffi::gst_registry_feature_filter(self.to_glib_none().0, filter, first.to_glib(), super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
     pub fn find_feature(&self, name: &str, type_: glib::types::Type) -> Option<PluginFeature> {
         unsafe {
@@ -96,9 +107,20 @@ impl Registry {
         }
     }
 
-    //pub fn plugin_filter<P: Into<Option</*Unimplemented*/Fundamental: Pointer>>>(&self, filter: /*Unknown conversion*//*Unimplemented*/PluginFilter, first: bool, user_data: P) -> Vec<Plugin> {
-    //    unsafe { TODO: call ffi::gst_registry_plugin_filter() }
-    //}
+    pub fn plugin_filter<P: FnMut(&Plugin) -> bool>(&self, filter: P, first: bool) -> Vec<Plugin> {
+        let filter_data: P = filter;
+        unsafe extern "C" fn filter_func<P: FnMut(&Plugin) -> bool>(plugin: *mut ffi::GstPlugin, user_data: glib_ffi::gpointer) -> glib_ffi::gboolean {
+            let plugin = from_glib_borrow(plugin);
+            let callback: *mut P = user_data as *const _ as usize as *mut P;
+            let res = (*callback)(&plugin);
+            res.to_glib()
+        }
+        let filter = Some(filter_func::<P> as _);
+        let super_callback0: &P = &filter_data;
+        unsafe {
+            FromGlibPtrContainer::from_glib_full(ffi::gst_registry_plugin_filter(self.to_glib_none().0, filter, first.to_glib(), super_callback0 as *const _ as usize as *mut _))
+        }
+    }
 
     pub fn remove_feature<P: IsA<PluginFeature>>(&self, feature: &P) {
         unsafe {
@@ -127,17 +149,17 @@ impl Registry {
 
     pub fn connect_feature_added<F: Fn(&Registry, &PluginFeature) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Registry, &PluginFeature) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"feature-added\0".as_ptr() as *const _,
-                transmute(feature_added_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(feature_added_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_plugin_added<F: Fn(&Registry, &Plugin) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Registry, &Plugin) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"plugin-added\0".as_ptr() as *const _,
-                transmute(plugin_added_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(plugin_added_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -145,12 +167,12 @@ impl Registry {
 unsafe impl Send for Registry {}
 unsafe impl Sync for Registry {}
 
-unsafe extern "C" fn feature_added_trampoline(this: *mut ffi::GstRegistry, feature: *mut ffi::GstPluginFeature, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Registry, &PluginFeature) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn feature_added_trampoline<F: Fn(&Registry, &PluginFeature) + Send + Sync + 'static>(this: *mut ffi::GstRegistry, feature: *mut ffi::GstPluginFeature, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(feature))
 }
 
-unsafe extern "C" fn plugin_added_trampoline(this: *mut ffi::GstRegistry, plugin: *mut ffi::GstPlugin, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Registry, &Plugin) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn plugin_added_trampoline<F: Fn(&Registry, &Plugin) + Send + Sync + 'static>(this: *mut ffi::GstRegistry, plugin: *mut ffi::GstPlugin, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this), &from_glib_borrow(plugin))
 }
diff --git a/gstreamer/src/auto/stream.rs b/gstreamer/src/auto/stream.rs
index f8039fd41..07ccfd9bb 100644
--- a/gstreamer/src/auto/stream.rs
+++ b/gstreamer/src/auto/stream.rs
@@ -160,33 +160,33 @@ impl Stream {
 
     pub fn connect_property_caps_notify<F: Fn(&Stream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Stream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::caps\0".as_ptr() as *const _,
-                transmute(notify_caps_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_caps_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_stream_flags_notify<F: Fn(&Stream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Stream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::stream-flags\0".as_ptr() as *const _,
-                transmute(notify_stream_flags_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_stream_flags_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_stream_type_notify<F: Fn(&Stream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Stream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::stream-type\0".as_ptr() as *const _,
-                transmute(notify_stream_type_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_stream_type_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 
     pub fn connect_property_tags_notify<F: Fn(&Stream) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Stream) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::tags\0".as_ptr() as *const _,
-                transmute(notify_tags_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_tags_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -194,22 +194,22 @@ impl Stream {
 unsafe impl Send for Stream {}
 unsafe impl Sync for Stream {}
 
-unsafe extern "C" fn notify_caps_trampoline(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Stream) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_caps_trampoline<F: Fn(&Stream) + Send + Sync + 'static>(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_stream_flags_trampoline(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Stream) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_stream_flags_trampoline<F: Fn(&Stream) + Send + Sync + 'static>(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_stream_type_trampoline(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Stream) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_stream_type_trampoline<F: Fn(&Stream) + Send + Sync + 'static>(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
 
-unsafe extern "C" fn notify_tags_trampoline(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&Stream) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_tags_trampoline<F: Fn(&Stream) + Send + Sync + 'static>(this: *mut ffi::GstStream, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer/src/auto/stream_collection.rs b/gstreamer/src/auto/stream_collection.rs
index e660469d1..5eb2fbe45 100644
--- a/gstreamer/src/auto/stream_collection.rs
+++ b/gstreamer/src/auto/stream_collection.rs
@@ -69,9 +69,9 @@ impl StreamCollection {
 
     pub fn connect_property_upstream_id_notify<F: Fn(&StreamCollection) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&StreamCollection) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::upstream-id\0".as_ptr() as *const _,
-                transmute(notify_upstream_id_trampoline as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_upstream_id_trampoline::<F> as usize)), Box_::into_raw(f))
         }
     }
 }
@@ -79,7 +79,7 @@ impl StreamCollection {
 unsafe impl Send for StreamCollection {}
 unsafe impl Sync for StreamCollection {}
 
-unsafe extern "C" fn notify_upstream_id_trampoline(this: *mut ffi::GstStreamCollection, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
-    let f: &&(Fn(&StreamCollection) + Send + Sync + 'static) = transmute(f);
+unsafe extern "C" fn notify_upstream_id_trampoline<F: Fn(&StreamCollection) + Send + Sync + 'static>(this: *mut ffi::GstStreamCollection, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer) {
+    let f: &F = transmute(f);
     f(&from_glib_borrow(this))
 }
diff --git a/gstreamer/src/auto/system_clock.rs b/gstreamer/src/auto/system_clock.rs
index acc347086..0cd3dc3f5 100644
--- a/gstreamer/src/auto/system_clock.rs
+++ b/gstreamer/src/auto/system_clock.rs
@@ -73,15 +73,15 @@ impl<O: IsA<SystemClock>> SystemClockExt for O {
 
     fn connect_property_clock_type_notify<F: Fn(&Self) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe {
-            let f: Box_<Box_<Fn(&Self) + Send + Sync + 'static>> = Box_::new(Box_::new(f));
+            let f: Box_<F> = Box_::new(f);
             connect_raw(self.as_ptr() as *mut _, b"notify::clock-type\0".as_ptr() as *const _,
-                transmute(notify_clock_type_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
+                Some(transmute(notify_clock_type_trampoline::<Self, F> as usize)), Box_::into_raw(f))
         }
     }
 }
 
-unsafe extern "C" fn notify_clock_type_trampoline<P>(this: *mut ffi::GstSystemClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
+unsafe extern "C" fn notify_clock_type_trampoline<P, F: Fn(&P) + Send + Sync + 'static>(this: *mut ffi::GstSystemClock, _param_spec: glib_ffi::gpointer, f: glib_ffi::gpointer)
 where P: IsA<SystemClock> {
-    let f: &&(Fn(&P) + Send + Sync + 'static) = transmute(f);
+    let f: &F = transmute(f);
     f(&SystemClock::from_glib_borrow(this).unsafe_cast())
 }
diff --git a/gstreamer/src/auto/versions.txt b/gstreamer/src/auto/versions.txt
index 502cec64b..48014f977 100644
--- a/gstreamer/src/auto/versions.txt
+++ b/gstreamer/src/auto/versions.txt
@@ -1,2 +1,2 @@
-Generated by gir (https://github.com/gtk-rs/gir @ 4620f19)
+Generated by gir (https://github.com/gtk-rs/gir @ eb84608)
 from gir-files (https://github.com/gtk-rs/gir-files @ ???)