diff --git a/gstreamer-rtp/Cargo.toml b/gstreamer-rtp/Cargo.toml
index 2010a3e02..6dc780f71 100644
--- a/gstreamer-rtp/Cargo.toml
+++ b/gstreamer-rtp/Cargo.toml
@@ -16,6 +16,7 @@ rust-version = "1.56"
 [dependencies]
 bitflags = "1.0"
 once_cell = "1.0"
+libc = "0.2"
 ffi = { package = "gstreamer-rtp-sys", path = "sys", features = ["v1_8"] }
 glib = { git = "https://github.com/gtk-rs/gtk-rs-core" }
 gst = { package = "gstreamer", path = "../gstreamer" }
diff --git a/gstreamer-rtp/src/lib.rs b/gstreamer-rtp/src/lib.rs
index 2b2b3a616..f268b19a3 100644
--- a/gstreamer-rtp/src/lib.rs
+++ b/gstreamer-rtp/src/lib.rs
@@ -30,6 +30,8 @@ mod auto;
 pub use crate::auto::functions::*;
 pub use crate::auto::*;
 
+pub mod subclass;
+
 pub mod rtp_buffer;
 pub use crate::rtp_buffer::{compare_seqnum, RTPBuffer};
 #[cfg(any(feature = "v1_20", feature = "dox"))]
diff --git a/gstreamer-rtp/src/subclass/mod.rs b/gstreamer-rtp/src/subclass/mod.rs
new file mode 100644
index 000000000..23c8d5a0d
--- /dev/null
+++ b/gstreamer-rtp/src/subclass/mod.rs
@@ -0,0 +1,16 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+#![allow(clippy::cast_ptr_alignment)]
+
+#[cfg(any(feature = "v1_20", feature = "dox"))]
+#[cfg_attr(feature = "dox", doc(cfg(feature = "v1_20")))]
+mod rtp_header_extension;
+
+pub mod prelude {
+    #[doc(hidden)]
+    pub use gst::subclass::prelude::*;
+
+    #[cfg(any(feature = "v1_20", feature = "dox"))]
+    #[cfg_attr(feature = "dox", doc(cfg(feature = "v1_20")))]
+    pub use super::rtp_header_extension::{RTPHeaderExtensionImpl, RTPHeaderExtensionImplExt};
+}
diff --git a/gstreamer-rtp/src/subclass/rtp_header_extension.rs b/gstreamer-rtp/src/subclass/rtp_header_extension.rs
new file mode 100644
index 000000000..c439eac48
--- /dev/null
+++ b/gstreamer-rtp/src/subclass/rtp_header_extension.rs
@@ -0,0 +1,513 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+use super::prelude::*;
+use glib::prelude::*;
+use glib::subclass::prelude::*;
+use glib::translate::*;
+
+pub trait RTPHeaderExtensionImpl: RTPHeaderExtensionImplExt + ElementImpl {
+    const URI: &'static str;
+
+    fn supported_flags(&self, element: &Self::Type) -> crate::RTPHeaderExtensionFlags {
+        self.parent_supported_flags(element)
+    }
+
+    fn max_size(&self, element: &Self::Type, input: &gst::BufferRef) -> usize {
+        self.parent_max_size(element, input)
+    }
+
+    fn write(
+        &self,
+        element: &Self::Type,
+        input: &gst::BufferRef,
+        write_flags: crate::RTPHeaderExtensionFlags,
+        output: &mut gst::BufferRef,
+        output_data: &mut [u8],
+    ) -> Result<usize, gst::LoggableError> {
+        self.parent_write(element, input, write_flags, output, output_data)
+    }
+
+    fn read(
+        &self,
+        element: &Self::Type,
+        read_flags: crate::RTPHeaderExtensionFlags,
+        input_data: &[u8],
+        output: &mut gst::BufferRef,
+    ) -> Result<(), gst::LoggableError> {
+        self.parent_read(element, read_flags, input_data, output)
+    }
+
+    fn set_non_rtp_sink_caps(
+        &self,
+        element: &Self::Type,
+        caps: &gst::Caps,
+    ) -> Result<(), gst::LoggableError> {
+        self.parent_set_non_rtp_sink_caps(element, caps)
+    }
+
+    fn update_non_rtp_src_caps(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError> {
+        self.parent_update_non_rtp_src_caps(element, caps)
+    }
+
+    fn set_attributes(
+        &self,
+        element: &Self::Type,
+        direction: crate::RTPHeaderExtensionDirection,
+        attributes: &str,
+    ) -> Result<(), gst::LoggableError> {
+        self.parent_set_attributes(element, direction, attributes)
+    }
+
+    fn set_caps_from_attributes(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError> {
+        self.parent_set_caps_from_attributes(element, caps)
+    }
+}
+
+pub trait RTPHeaderExtensionImplExt: ObjectSubclass {
+    fn parent_supported_flags(&self, element: &Self::Type) -> crate::RTPHeaderExtensionFlags;
+    fn parent_max_size(&self, element: &Self::Type, input: &gst::BufferRef) -> usize;
+    fn parent_write(
+        &self,
+        element: &Self::Type,
+        input: &gst::BufferRef,
+        write_flags: crate::RTPHeaderExtensionFlags,
+        output: &mut gst::BufferRef,
+        output_data: &mut [u8],
+    ) -> Result<usize, gst::LoggableError>;
+    fn parent_read(
+        &self,
+        element: &Self::Type,
+        read_flags: crate::RTPHeaderExtensionFlags,
+        input_data: &[u8],
+        output: &mut gst::BufferRef,
+    ) -> Result<(), gst::LoggableError>;
+    fn parent_set_non_rtp_sink_caps(
+        &self,
+        element: &Self::Type,
+        caps: &gst::Caps,
+    ) -> Result<(), gst::LoggableError>;
+    fn parent_update_non_rtp_src_caps(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError>;
+    fn parent_set_attributes(
+        &self,
+        element: &Self::Type,
+        direction: crate::RTPHeaderExtensionDirection,
+        attributes: &str,
+    ) -> Result<(), gst::LoggableError>;
+    fn parent_set_caps_from_attributes(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError>;
+}
+
+impl<T: RTPHeaderExtensionImpl> RTPHeaderExtensionImplExt for T {
+    fn parent_supported_flags(&self, element: &Self::Type) -> crate::RTPHeaderExtensionFlags {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            let f = (*parent_class)
+                .get_supported_flags
+                .expect("no parent \"get_supported_flags\" implementation");
+            from_glib(f(element
+                .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                .to_glib_none()
+                .0))
+        }
+    }
+
+    fn parent_max_size(&self, element: &Self::Type, input: &gst::BufferRef) -> usize {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            let f = (*parent_class)
+                .get_max_size
+                .expect("no parent \"get_max_size\" implementation");
+            f(
+                element
+                    .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                    .to_glib_none()
+                    .0,
+                input.as_ptr(),
+            )
+        }
+    }
+
+    fn parent_write(
+        &self,
+        element: &Self::Type,
+        input: &gst::BufferRef,
+        write_flags: crate::RTPHeaderExtensionFlags,
+        output: &mut gst::BufferRef,
+        output_data: &mut [u8],
+    ) -> Result<usize, gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            let f = (*parent_class)
+                .write
+                .expect("no parent \"write\" implementation");
+
+            let res = f(
+                element
+                    .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                    .to_glib_none()
+                    .0,
+                input.as_ptr(),
+                write_flags.into_glib(),
+                output.as_mut_ptr(),
+                output_data.as_mut_ptr(),
+                output_data.len(),
+            );
+
+            if res < 0 {
+                Err(gst::loggable_error!(
+                    gst::CAT_RUST,
+                    "Failed to write extension data"
+                ))
+            } else {
+                Ok(res as usize)
+            }
+        }
+    }
+
+    fn parent_read(
+        &self,
+        element: &Self::Type,
+        read_flags: crate::RTPHeaderExtensionFlags,
+        input_data: &[u8],
+        output: &mut gst::BufferRef,
+    ) -> Result<(), gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            let f = (*parent_class)
+                .read
+                .expect("no parent \"read\" implementation");
+
+            gst::result_from_gboolean!(
+                f(
+                    element
+                        .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                        .to_glib_none()
+                        .0,
+                    read_flags.into_glib(),
+                    input_data.as_ptr(),
+                    input_data.len(),
+                    output.as_mut_ptr(),
+                ),
+                gst::CAT_RUST,
+                "Failed to read extension data",
+            )
+        }
+    }
+
+    fn parent_set_non_rtp_sink_caps(
+        &self,
+        element: &Self::Type,
+        caps: &gst::Caps,
+    ) -> Result<(), gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            if let Some(f) = (*parent_class).set_non_rtp_sink_caps {
+                gst::result_from_gboolean!(
+                    f(
+                        element
+                            .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                            .to_glib_none()
+                            .0,
+                        caps.as_mut_ptr(),
+                    ),
+                    gst::CAT_RUST,
+                    "Failed to set non-RTP sink caps",
+                )
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    fn parent_update_non_rtp_src_caps(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            if let Some(f) = (*parent_class).update_non_rtp_src_caps {
+                gst::result_from_gboolean!(
+                    f(
+                        element
+                            .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                            .to_glib_none()
+                            .0,
+                        caps.as_mut_ptr(),
+                    ),
+                    gst::CAT_RUST,
+                    "Failed to update non-RTP source caps",
+                )
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    fn parent_set_attributes(
+        &self,
+        element: &Self::Type,
+        direction: crate::RTPHeaderExtensionDirection,
+        attributes: &str,
+    ) -> Result<(), gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            if let Some(f) = (*parent_class).set_attributes {
+                gst::result_from_gboolean!(
+                    f(
+                        element
+                            .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                            .to_glib_none()
+                            .0,
+                        direction.into_glib(),
+                        attributes.to_glib_none().0,
+                    ),
+                    gst::CAT_RUST,
+                    "Failed to set attributes",
+                )
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    fn parent_set_caps_from_attributes(
+        &self,
+        element: &Self::Type,
+        caps: &mut gst::CapsRef,
+    ) -> Result<(), gst::LoggableError> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GstRTPHeaderExtensionClass;
+            let f = (*parent_class)
+                .set_caps_from_attributes
+                .expect("no parent \"set_caps_from_attributes\" implementation");
+
+            gst::result_from_gboolean!(
+                f(
+                    element
+                        .unsafe_cast_ref::<crate::RTPHeaderExtension>()
+                        .to_glib_none()
+                        .0,
+                    caps.as_mut_ptr(),
+                ),
+                gst::CAT_RUST,
+                "Failed to set caps from attributes",
+            )
+        }
+    }
+}
+
+unsafe impl<T: RTPHeaderExtensionImpl> IsSubclassable<T> for crate::RTPHeaderExtension {
+    fn class_init(klass: &mut glib::Class<Self>) {
+        Self::parent_class_init::<T>(klass);
+        let klass = klass.as_mut();
+        klass.get_supported_flags = Some(get_supported_flags::<T>);
+        klass.get_max_size = Some(get_max_size::<T>);
+        klass.write = Some(write::<T>);
+        klass.read = Some(read::<T>);
+        klass.set_non_rtp_sink_caps = Some(set_non_rtp_sink_caps::<T>);
+        klass.update_non_rtp_src_caps = Some(update_non_rtp_src_caps::<T>);
+        klass.set_attributes = Some(set_attributes::<T>);
+        klass.set_caps_from_attributes = Some(set_caps_from_attributes::<T>);
+
+        unsafe {
+            ffi::gst_rtp_header_extension_class_set_uri(&mut *klass, T::URI.to_glib_none().0);
+        }
+    }
+}
+
+unsafe extern "C" fn get_supported_flags<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+) -> ffi::GstRTPHeaderExtensionFlags {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(
+        &wrap,
+        imp.panicked(),
+        crate::RTPHeaderExtensionFlags::empty(),
+        { imp.supported_flags(wrap.unsafe_cast_ref()) }
+    )
+    .into_glib()
+}
+
+unsafe extern "C" fn get_max_size<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    input: *const gst::ffi::GstBuffer,
+) -> usize {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), 0, {
+        imp.max_size(wrap.unsafe_cast_ref(), gst::BufferRef::from_ptr(input))
+    })
+}
+
+unsafe extern "C" fn write<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    input: *const gst::ffi::GstBuffer,
+    write_flags: ffi::GstRTPHeaderExtensionFlags,
+    output: *mut gst::ffi::GstBuffer,
+    output_data: *mut u8,
+    output_data_len: usize,
+) -> isize {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), -1, {
+        match imp.write(
+            wrap.unsafe_cast_ref(),
+            gst::BufferRef::from_ptr(input),
+            from_glib(write_flags),
+            gst::BufferRef::from_mut_ptr(output),
+            std::slice::from_raw_parts_mut(output_data, output_data_len),
+        ) {
+            Ok(len) => len as isize,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                -1
+            }
+        }
+    })
+}
+
+unsafe extern "C" fn read<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    read_flags: ffi::GstRTPHeaderExtensionFlags,
+    input_data: *const u8,
+    input_data_len: usize,
+    output: *mut gst::ffi::GstBuffer,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), false, {
+        match imp.read(
+            wrap.unsafe_cast_ref(),
+            from_glib(read_flags),
+            std::slice::from_raw_parts(input_data, input_data_len),
+            gst::BufferRef::from_mut_ptr(output),
+        ) {
+            Ok(_) => true,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                false
+            }
+        }
+    })
+    .into_glib()
+}
+
+unsafe extern "C" fn set_non_rtp_sink_caps<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    caps: *mut gst::ffi::GstCaps,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), false, {
+        match imp.set_non_rtp_sink_caps(wrap.unsafe_cast_ref(), &from_glib_borrow(caps)) {
+            Ok(_) => true,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                false
+            }
+        }
+    })
+    .into_glib()
+}
+
+unsafe extern "C" fn update_non_rtp_src_caps<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    caps: *mut gst::ffi::GstCaps,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), false, {
+        match imp.update_non_rtp_src_caps(wrap.unsafe_cast_ref(), gst::CapsRef::from_mut_ptr(caps))
+        {
+            Ok(_) => true,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                false
+            }
+        }
+    })
+    .into_glib()
+}
+
+unsafe extern "C" fn set_attributes<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    direction: ffi::GstRTPHeaderExtensionDirection,
+    attributes: *const libc::c_char,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), false, {
+        match imp.set_attributes(
+            wrap.unsafe_cast_ref(),
+            from_glib(direction),
+            &glib::GString::from_glib_borrow(attributes),
+        ) {
+            Ok(_) => true,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                false
+            }
+        }
+    })
+    .into_glib()
+}
+
+unsafe extern "C" fn set_caps_from_attributes<T: RTPHeaderExtensionImpl>(
+    ptr: *mut ffi::GstRTPHeaderExtension,
+    caps: *mut gst::ffi::GstCaps,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: Borrowed<crate::RTPHeaderExtension> = from_glib_borrow(ptr);
+
+    gst::panic_to_error!(&wrap, imp.panicked(), false, {
+        match imp.set_caps_from_attributes(wrap.unsafe_cast_ref(), gst::CapsRef::from_mut_ptr(caps))
+        {
+            Ok(_) => true,
+            Err(err) => {
+                err.log_with_object(&*wrap);
+                false
+            }
+        }
+    })
+    .into_glib()
+}