diff --git a/Gir_GstApp.toml b/Gir_GstApp.toml
index 69bf3f53a..6df5c2151 100644
--- a/Gir_GstApp.toml
+++ b/Gir_GstApp.toml
@@ -55,6 +55,12 @@ trait = false
     # Action signal
     ignore = true
 
+    [[object.function]]
+    name = "set_caps"
+        [[object.function.parameter]]
+            name = "caps"
+            nullable = true
+
 [[object]]
 name = "GstApp.AppSrc"
 status = "generate"
@@ -80,6 +86,12 @@ trait = false
     # Action signal
     ignore = true
 
+    [[object.function]]
+    name = "set_caps"
+        [[object.function.parameter]]
+            name = "caps"
+            nullable = true
+
 [[object]]
 name = "Gst.Structure"
 status = "manual"
diff --git a/gstreamer-app/src/auto/app_sink.rs b/gstreamer-app/src/auto/app_sink.rs
index e29a9cede..90b19024b 100644
--- a/gstreamer-app/src/auto/app_sink.rs
+++ b/gstreamer-app/src/auto/app_sink.rs
@@ -97,9 +97,11 @@ impl AppSink {
     //    unsafe { TODO: call ffi::gst_app_sink_set_callbacks() }
     //}
 
-    pub fn set_caps(&self, caps: &gst::Caps) {
+    pub fn set_caps<'a, P: Into<Option<&'a gst::Caps>>>(&self, caps: P) {
+        let caps = caps.into();
+        let caps = caps.to_glib_none();
         unsafe {
-            ffi::gst_app_sink_set_caps(self.to_glib_none().0, caps.to_glib_none().0);
+            ffi::gst_app_sink_set_caps(self.to_glib_none().0, caps.0);
         }
     }
 
diff --git a/gstreamer-app/src/auto/app_src.rs b/gstreamer-app/src/auto/app_src.rs
index bb0e3e955..c41e3e248 100644
--- a/gstreamer-app/src/auto/app_src.rs
+++ b/gstreamer-app/src/auto/app_src.rs
@@ -101,9 +101,11 @@ impl AppSrc {
     //    unsafe { TODO: call ffi::gst_app_src_set_callbacks() }
     //}
 
-    pub fn set_caps(&self, caps: &gst::Caps) {
+    pub fn set_caps<'a, P: Into<Option<&'a gst::Caps>>>(&self, caps: P) {
+        let caps = caps.into();
+        let caps = caps.to_glib_none();
         unsafe {
-            ffi::gst_app_src_set_caps(self.to_glib_none().0, caps.to_glib_none().0);
+            ffi::gst_app_src_set_caps(self.to_glib_none().0, caps.0);
         }
     }