diff --git a/gstreamer-app/src/app_sink.rs b/gstreamer-app/src/app_sink.rs
index b84285990..1d00f6495 100644
--- a/gstreamer-app/src/app_sink.rs
+++ b/gstreamer-app/src/app_sink.rs
@@ -4,7 +4,6 @@ use crate::AppSink;
 use glib::ffi::gpointer;
 use glib::prelude::*;
 use glib::translate::*;
-use std::cell::RefCell;
 use std::mem;
 use std::panic;
 use std::ptr;
@@ -22,18 +21,14 @@ use {
 
 #[allow(clippy::type_complexity)]
 pub struct AppSinkCallbacks {
-    eos: Option<RefCell<Box<dyn FnMut(&AppSink) + Send + 'static>>>,
+    eos: Option<Box<dyn FnMut(&AppSink) + Send + 'static>>,
     new_preroll: Option<
-        RefCell<
-            Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
-        >,
+        Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
     >,
     new_sample: Option<
-        RefCell<
-            Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
-        >,
+        Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
     >,
-    new_event: Option<RefCell<Box<dyn FnMut(&AppSink) -> bool + Send + 'static>>>,
+    new_event: Option<Box<dyn FnMut(&AppSink) -> bool + Send + 'static>>,
     panicked: AtomicBool,
     callbacks: ffi::GstAppSinkCallbacks,
 }
@@ -56,24 +51,20 @@ impl AppSinkCallbacks {
 #[allow(clippy::type_complexity)]
 #[must_use = "The builder must be built to be used"]
 pub struct AppSinkCallbacksBuilder {
-    eos: Option<RefCell<Box<dyn FnMut(&AppSink) + Send + 'static>>>,
+    eos: Option<Box<dyn FnMut(&AppSink) + Send + 'static>>,
     new_preroll: Option<
-        RefCell<
-            Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
-        >,
+        Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
     >,
     new_sample: Option<
-        RefCell<
-            Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
-        >,
+        Box<dyn FnMut(&AppSink) -> Result<gst::FlowSuccess, gst::FlowError> + Send + 'static>,
     >,
-    new_event: Option<RefCell<Box<dyn FnMut(&AppSink) -> bool + Send + 'static>>>,
+    new_event: Option<Box<dyn FnMut(&AppSink) -> bool + Send + 'static>>,
 }
 
 impl AppSinkCallbacksBuilder {
     pub fn eos<F: FnMut(&AppSink) + Send + 'static>(self, eos: F) -> Self {
         Self {
-            eos: Some(RefCell::new(Box::new(eos))),
+            eos: Some(Box::new(eos)),
             ..self
         }
     }
@@ -85,7 +76,7 @@ impl AppSinkCallbacksBuilder {
         new_preroll: F,
     ) -> Self {
         Self {
-            new_preroll: Some(RefCell::new(Box::new(new_preroll))),
+            new_preroll: Some(Box::new(new_preroll)),
             ..self
         }
     }
@@ -97,7 +88,7 @@ impl AppSinkCallbacksBuilder {
         new_sample: F,
     ) -> Self {
         Self {
-            new_sample: Some(RefCell::new(Box::new(new_sample))),
+            new_sample: Some(Box::new(new_sample)),
             ..self
         }
     }
@@ -106,7 +97,7 @@ impl AppSinkCallbacksBuilder {
     #[cfg_attr(feature = "dox", doc(cfg(feature = "v1_20")))]
     pub fn new_event<F: FnMut(&AppSink) -> bool + Send + 'static>(self, new_event: F) -> Self {
         Self {
-            new_event: Some(RefCell::new(Box::new(new_event))),
+            new_event: Some(Box::new(new_event)),
             ..self
         }
     }
@@ -159,21 +150,21 @@ fn post_panic_error_message(element: &AppSink, err: &dyn std::any::Any) {
 }
 
 unsafe extern "C" fn trampoline_eos(appsink: *mut ffi::GstAppSink, callbacks: gpointer) {
-    let callbacks = &*(callbacks as *const AppSinkCallbacks);
+    let callbacks = callbacks as *mut AppSinkCallbacks;
     let element: Borrowed<AppSink> = from_glib_borrow(appsink);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSink> = from_glib_borrow(appsink);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return;
     }
 
-    if let Some(ref eos) = callbacks.eos {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| (*eos.borrow_mut())(&element)));
+    if let Some(ref mut eos) = (*callbacks).eos {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| eos(&element)));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
             }
         }
@@ -184,23 +175,21 @@ unsafe extern "C" fn trampoline_new_preroll(
     appsink: *mut ffi::GstAppSink,
     callbacks: gpointer,
 ) -> gst::ffi::GstFlowReturn {
-    let callbacks = &*(callbacks as *const AppSinkCallbacks);
+    let callbacks = callbacks as *mut AppSinkCallbacks;
     let element: Borrowed<AppSink> = from_glib_borrow(appsink);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSink> = from_glib_borrow(appsink);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return gst::FlowReturn::Error.into_glib();
     }
 
-    let ret = if let Some(ref new_preroll) = callbacks.new_preroll {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-            (*new_preroll.borrow_mut())(&element).into()
-        }));
+    let ret = if let Some(ref mut new_preroll) = (*callbacks).new_preroll {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| new_preroll(&element).into()));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
 
                 gst::FlowReturn::Error
@@ -217,23 +206,21 @@ unsafe extern "C" fn trampoline_new_sample(
     appsink: *mut ffi::GstAppSink,
     callbacks: gpointer,
 ) -> gst::ffi::GstFlowReturn {
-    let callbacks = &*(callbacks as *const AppSinkCallbacks);
+    let callbacks = callbacks as *mut AppSinkCallbacks;
     let element: Borrowed<AppSink> = from_glib_borrow(appsink);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSink> = from_glib_borrow(appsink);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return gst::FlowReturn::Error.into_glib();
     }
 
-    let ret = if let Some(ref new_sample) = callbacks.new_sample {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-            (*new_sample.borrow_mut())(&element).into()
-        }));
+    let ret = if let Some(ref mut new_sample) = (*callbacks).new_sample {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| new_sample(&element).into()));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
 
                 gst::FlowReturn::Error
@@ -250,23 +237,21 @@ unsafe extern "C" fn trampoline_new_event(
     appsink: *mut ffi::GstAppSink,
     callbacks: gpointer,
 ) -> glib::ffi::gboolean {
-    let callbacks = &*(callbacks as *const AppSinkCallbacks);
+    let callbacks = callbacks as *mut AppSinkCallbacks;
     let element: Borrowed<AppSink> = from_glib_borrow(appsink);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSink> = from_glib_borrow(appsink);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return false.into_glib();
     }
 
-    let ret = if let Some(ref new_event) = callbacks.new_event {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-            (*new_event.borrow_mut())(&element)
-        }));
+    let ret = if let Some(ref mut new_event) = (*callbacks).new_event {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| new_event(&element)));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
 
                 false
diff --git a/gstreamer-app/src/app_src.rs b/gstreamer-app/src/app_src.rs
index b9e2c99ae..563aa344b 100644
--- a/gstreamer-app/src/app_src.rs
+++ b/gstreamer-app/src/app_src.rs
@@ -6,7 +6,6 @@ use glib::prelude::*;
 use glib::translate::*;
 
 use crate::AppSrc;
-use std::cell::RefCell;
 use std::mem;
 use std::panic;
 use std::pin::Pin;
@@ -17,7 +16,7 @@ use std::task::{Context, Poll, Waker};
 
 #[allow(clippy::type_complexity)]
 pub struct AppSrcCallbacks {
-    need_data: Option<RefCell<Box<dyn FnMut(&AppSrc, u32) + Send + 'static>>>,
+    need_data: Option<Box<dyn FnMut(&AppSrc, u32) + Send + 'static>>,
     enough_data: Option<Box<dyn Fn(&AppSrc) + Send + Sync + 'static>>,
     seek_data: Option<Box<dyn Fn(&AppSrc, u64) -> bool + Send + Sync + 'static>>,
     panicked: AtomicBool,
@@ -42,7 +41,7 @@ impl AppSrcCallbacks {
 #[allow(clippy::type_complexity)]
 #[must_use = "The builder must be built to be used"]
 pub struct AppSrcCallbacksBuilder {
-    need_data: Option<RefCell<Box<dyn FnMut(&AppSrc, u32) + Send + 'static>>>,
+    need_data: Option<Box<dyn FnMut(&AppSrc, u32) + Send + 'static>>,
     enough_data: Option<Box<dyn Fn(&AppSrc) + Send + Sync + 'static>>,
     seek_data: Option<Box<dyn Fn(&AppSrc, u64) -> bool + Send + Sync + 'static>>,
 }
@@ -50,7 +49,7 @@ pub struct AppSrcCallbacksBuilder {
 impl AppSrcCallbacksBuilder {
     pub fn need_data<F: FnMut(&AppSrc, u32) + Send + 'static>(self, need_data: F) -> Self {
         Self {
-            need_data: Some(RefCell::new(Box::new(need_data))),
+            need_data: Some(Box::new(need_data)),
             ..self
         }
     }
@@ -126,23 +125,21 @@ unsafe extern "C" fn trampoline_need_data(
     length: u32,
     callbacks: gpointer,
 ) {
-    let callbacks = &*(callbacks as *const AppSrcCallbacks);
+    let callbacks = callbacks as *mut AppSrcCallbacks;
     let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return;
     }
 
-    if let Some(ref need_data) = callbacks.need_data {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-            (*need_data.borrow_mut())(&element, length)
-        }));
+    if let Some(ref mut need_data) = (*callbacks).need_data {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| need_data(&element, length)));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
             }
         }
@@ -150,21 +147,21 @@ unsafe extern "C" fn trampoline_need_data(
 }
 
 unsafe extern "C" fn trampoline_enough_data(appsrc: *mut ffi::GstAppSrc, callbacks: gpointer) {
-    let callbacks = &*(callbacks as *const AppSrcCallbacks);
+    let callbacks = callbacks as *const AppSrcCallbacks;
     let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return;
     }
 
-    if let Some(ref enough_data) = callbacks.enough_data {
-        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| (*enough_data)(&element)));
+    if let Some(ref enough_data) = (*callbacks).enough_data {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| enough_data(&element)));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
             }
         }
@@ -176,22 +173,21 @@ unsafe extern "C" fn trampoline_seek_data(
     offset: u64,
     callbacks: gpointer,
 ) -> gboolean {
-    let callbacks = &*(callbacks as *const AppSrcCallbacks);
+    let callbacks = callbacks as *const AppSrcCallbacks;
     let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
 
-    if callbacks.panicked.load(Ordering::Relaxed) {
+    if (*callbacks).panicked.load(Ordering::Relaxed) {
         let element: Borrowed<AppSrc> = from_glib_borrow(appsrc);
         gst::element_error!(element, gst::LibraryError::Failed, ["Panicked"]);
         return false.into_glib();
     }
 
-    let ret = if let Some(ref seek_data) = callbacks.seek_data {
-        let result =
-            panic::catch_unwind(panic::AssertUnwindSafe(|| (*seek_data)(&element, offset)));
+    let ret = if let Some(ref seek_data) = (*callbacks).seek_data {
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| seek_data(&element, offset)));
         match result {
             Ok(result) => result,
             Err(err) => {
-                callbacks.panicked.store(true, Ordering::Relaxed);
+                (*callbacks).panicked.store(true, Ordering::Relaxed);
                 post_panic_error_message(&element, &err);
 
                 false
diff --git a/gstreamer-rtsp-server/src/rtsp_session_pool.rs b/gstreamer-rtsp-server/src/rtsp_session_pool.rs
index 403853d56..579a9dc62 100644
--- a/gstreamer-rtsp-server/src/rtsp_session_pool.rs
+++ b/gstreamer-rtsp-server/src/rtsp_session_pool.rs
@@ -5,15 +5,14 @@ use glib::ffi::{gboolean, gpointer};
 use glib::prelude::*;
 use glib::source::{Continue, Priority};
 use glib::translate::*;
-use std::cell::RefCell;
 use std::mem::transmute;
 
 unsafe extern "C" fn trampoline_watch<F: FnMut(&RTSPSessionPool) -> Continue + Send + 'static>(
     pool: *mut ffi::GstRTSPSessionPool,
     func: gpointer,
 ) -> gboolean {
-    let func: &RefCell<F> = &*(func as *const RefCell<F>);
-    (*func.borrow_mut())(&from_glib_borrow(pool)).into_glib()
+    let func: &mut F = &mut *(func as *mut F);
+    func(&from_glib_borrow(pool)).into_glib()
 }
 
 unsafe extern "C" fn destroy_closure_watch<
@@ -21,12 +20,12 @@ unsafe extern "C" fn destroy_closure_watch<
 >(
     ptr: gpointer,
 ) {
-    Box::<RefCell<F>>::from_raw(ptr as *mut _);
+    Box::<F>::from_raw(ptr as *mut _);
 }
 
 fn into_raw_watch<F: FnMut(&RTSPSessionPool) -> Continue + Send + 'static>(func: F) -> gpointer {
     #[allow(clippy::type_complexity)]
-    let func: Box<RefCell<F>> = Box::new(RefCell::new(func));
+    let func: Box<F> = Box::new(func);
     Box::into_raw(func) as gpointer
 }
 
diff --git a/gstreamer/src/bus.rs b/gstreamer/src/bus.rs
index 4ad3ec83b..9e24e58bf 100644
--- a/gstreamer/src/bus.rs
+++ b/gstreamer/src/bus.rs
@@ -7,7 +7,6 @@ use glib::ffi::{gboolean, gpointer};
 use glib::prelude::*;
 use glib::source::{Continue, Priority, SourceId};
 use glib::translate::*;
-use std::cell::RefCell;
 use std::future;
 use std::mem::transmute;
 use std::pin::Pin;
@@ -23,8 +22,8 @@ unsafe extern "C" fn trampoline_watch<F: FnMut(&Bus, &Message) -> Continue + Sen
     msg: *mut ffi::GstMessage,
     func: gpointer,
 ) -> gboolean {
-    let func: &RefCell<F> = &*(func as *const RefCell<F>);
-    (*func.borrow_mut())(&from_glib_borrow(bus), &Message::from_glib_borrow(msg)).into_glib()
+    let func: &mut F = &mut *(func as *mut F);
+    func(&from_glib_borrow(bus), &Message::from_glib_borrow(msg)).into_glib()
 }
 
 unsafe extern "C" fn destroy_closure_watch<
@@ -32,12 +31,12 @@ unsafe extern "C" fn destroy_closure_watch<
 >(
     ptr: gpointer,
 ) {
-    Box::<RefCell<F>>::from_raw(ptr as *mut _);
+    Box::<F>::from_raw(ptr as *mut _);
 }
 
 fn into_raw_watch<F: FnMut(&Bus, &Message) -> Continue + Send + 'static>(func: F) -> gpointer {
     #[allow(clippy::type_complexity)]
-    let func: Box<RefCell<F>> = Box::new(RefCell::new(func));
+    let func: Box<F> = Box::new(func);
     Box::into_raw(func) as gpointer
 }
 
@@ -46,22 +45,21 @@ unsafe extern "C" fn trampoline_watch_local<F: FnMut(&Bus, &Message) -> Continue
     msg: *mut ffi::GstMessage,
     func: gpointer,
 ) -> gboolean {
-    let func: &glib::thread_guard::ThreadGuard<RefCell<F>> =
-        &*(func as *const glib::thread_guard::ThreadGuard<RefCell<F>>);
-    (*func.get_ref().borrow_mut())(&from_glib_borrow(bus), &Message::from_glib_borrow(msg))
-        .into_glib()
+    let func: &mut glib::thread_guard::ThreadGuard<F> =
+        &mut *(func as *mut glib::thread_guard::ThreadGuard<F>);
+    (func.get_mut())(&from_glib_borrow(bus), &Message::from_glib_borrow(msg)).into_glib()
 }
 
 unsafe extern "C" fn destroy_closure_watch_local<F: FnMut(&Bus, &Message) -> Continue + 'static>(
     ptr: gpointer,
 ) {
-    Box::<glib::thread_guard::ThreadGuard<RefCell<F>>>::from_raw(ptr as *mut _);
+    Box::<glib::thread_guard::ThreadGuard<F>>::from_raw(ptr as *mut _);
 }
 
 fn into_raw_watch_local<F: FnMut(&Bus, &Message) -> Continue + 'static>(func: F) -> gpointer {
     #[allow(clippy::type_complexity)]
-    let func: Box<glib::thread_guard::ThreadGuard<RefCell<F>>> =
-        Box::new(glib::thread_guard::ThreadGuard::new(RefCell::new(func)));
+    let func: Box<glib::thread_guard::ThreadGuard<F>> =
+        Box::new(glib::thread_guard::ThreadGuard::new(func));
     Box::into_raw(func) as gpointer
 }
 
diff --git a/gstreamer/src/pad.rs b/gstreamer/src/pad.rs
index 1be11836f..2e1685035 100644
--- a/gstreamer/src/pad.rs
+++ b/gstreamer/src/pad.rs
@@ -19,7 +19,6 @@ use crate::QueryRef;
 use crate::StaticPadTemplate;
 use crate::{SpecificFormattedValue, SpecificFormattedValueIntrinsic};
 
-use std::cell::RefCell;
 use std::mem;
 use std::num::NonZeroU64;
 use std::ops::ControlFlow;
@@ -1597,18 +1596,18 @@ unsafe extern "C" fn destroy_closure<F>(ptr: gpointer) {
 }
 
 unsafe extern "C" fn trampoline_pad_task<F: FnMut() + Send + 'static>(func: gpointer) {
-    let func: &RefCell<F> = &*(func as *const RefCell<F>);
-    (*func.borrow_mut())()
+    let func: &mut F = &mut *(func as *mut F);
+    func()
 }
 
 fn into_raw_pad_task<F: FnMut() + Send + 'static>(func: F) -> gpointer {
     #[allow(clippy::type_complexity)]
-    let func: Box<RefCell<F>> = Box::new(RefCell::new(func));
+    let func: Box<F> = Box::new(func);
     Box::into_raw(func) as gpointer
 }
 
 unsafe extern "C" fn destroy_closure_pad_task<F>(ptr: gpointer) {
-    Box::<RefCell<F>>::from_raw(ptr as *mut _);
+    Box::<F>::from_raw(ptr as *mut _);
 }
 
 impl Pad {