diff --git a/gstreamer-editing-services/src/formatter.rs b/gstreamer-editing-services/src/formatter.rs
new file mode 100644
index 000000000..4f53f1ed5
--- /dev/null
+++ b/gstreamer-editing-services/src/formatter.rs
@@ -0,0 +1,73 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+use crate::prelude::*;
+use gst::glib::translate::*;
+
+pub trait FormatterExtManual: 'static {
+    fn can_load_uri(&self, uri: &str) -> Result<(), glib::Error>;
+    #[doc(alias = "ges_formatter_class_register_metas")]
+    fn register(
+        type_: glib::types::Type,
+        name: &str,
+        description: Option<&str>,
+        extensions: Option<&str>,
+        caps: Option<&str>,
+        version: f64,
+        rank: gst::Rank,
+    );
+}
+
+impl<O: IsA<crate::Formatter>> FormatterExtManual for O {
+    fn can_load_uri(&self, uri: &str) -> Result<(), glib::Error> {
+        unsafe {
+            let klass = self.class_of::<crate::Formatter>().unwrap();
+
+            let f = klass.as_ref().can_load_uri.ok_or_else(|| {
+                glib::Error::new(gst::CoreError::Failed, "No `can_load_uri` method defined")
+            })?;
+
+            let mut err = std::ptr::null_mut();
+            let res = f(
+                self.as_ref().to_glib_none().0,
+                uri.to_glib_none().0,
+                &mut err,
+            );
+
+            if res == glib::ffi::GTRUE {
+                Ok(())
+            } else {
+                Err(from_glib_full(err))
+            }
+        }
+    }
+
+    #[doc(alias = "ges_formatter_class_register_metas")]
+    fn register(
+        type_: glib::types::Type,
+        name: &str,
+        description: Option<&str>,
+        extensions: Option<&str>,
+        caps: Option<&str>,
+        version: f64,
+        rank: gst::Rank,
+    ) {
+        skip_assert_initialized!();
+
+        unsafe {
+            let klass = mut_override(
+                gst::glib::Class::<crate::Formatter>::from_type(type_)
+                    .unwrap()
+                    .as_ref(),
+            );
+
+            ffi::ges_formatter_class_register_metas(
+                klass,
+                name.to_glib_none().0,
+                description.to_glib_none().0,
+                extensions.to_glib_none().0,
+                caps.to_glib_none().0,
+                version,
+                rank.into_glib(),
+            );
+        }
+    }
+}
diff --git a/gstreamer-editing-services/src/lib.rs b/gstreamer-editing-services/src/lib.rs
index 405d92570..53fcdc2a4 100644
--- a/gstreamer-editing-services/src/lib.rs
+++ b/gstreamer-editing-services/src/lib.rs
@@ -54,7 +54,9 @@ macro_rules! skip_assert_initialized {
 #[allow(deprecated)]
 #[allow(unused_imports)]
 mod auto;
+mod formatter;
 pub use crate::auto::*;
+pub mod subclass;
 
 #[cfg(feature = "serde")]
 mod flag_serde;
@@ -65,9 +67,12 @@ pub mod prelude {
     #[doc(hidden)]
     pub use gio::prelude::*;
     #[doc(hidden)]
+    pub use glib::prelude::*;
+    #[doc(hidden)]
     pub use gst_base::prelude::*;
     #[doc(hidden)]
     pub use gst_pbutils::prelude::*;
 
     pub use crate::auto::traits::*;
+    pub use crate::formatter::FormatterExtManual;
 }
diff --git a/gstreamer-editing-services/src/subclass/formatter.rs b/gstreamer-editing-services/src/subclass/formatter.rs
new file mode 100644
index 000000000..744867e79
--- /dev/null
+++ b/gstreamer-editing-services/src/subclass/formatter.rs
@@ -0,0 +1,363 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+use crate::prelude::*;
+use crate::Formatter;
+use glib::{subclass::prelude::*, translate::*};
+
+pub trait FormatterImpl: FormatterImplExt + ObjectImpl + Send + Sync {
+    fn can_load_uri(&self, uri: &str) -> Result<(), glib::Error> {
+        self.parent_can_load_uri(uri)
+    }
+
+    fn load_from_uri(&self, timeline: &crate::Timeline, uri: &str) -> Result<(), glib::Error> {
+        self.parent_load_from_uri(timeline, uri)
+    }
+
+    fn save_to_uri(
+        &self,
+        timeline: &crate::Timeline,
+        uri: &str,
+        overwrite: bool,
+    ) -> Result<(), glib::Error> {
+        self.parent_save_to_uri(timeline, uri, overwrite)
+    }
+}
+
+pub trait FormatterImplExt: ObjectSubclass {
+    fn parent_can_load_uri(&self, uri: &str) -> Result<(), glib::Error>;
+
+    fn parent_load_from_uri(
+        &self,
+        timeline: &crate::Timeline,
+        uri: &str,
+    ) -> Result<(), glib::Error>;
+
+    fn parent_save_to_uri(
+        &self,
+        timeline: &crate::Timeline,
+        uri: &str,
+        overwrite: bool,
+    ) -> Result<(), glib::Error>;
+}
+
+impl<T: FormatterImpl> FormatterImplExt for T {
+    fn parent_can_load_uri(&self, uri: &str) -> Result<(), glib::Error> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GESFormatterClass;
+
+            let f = (*parent_class)
+                .can_load_uri
+                .expect("Missing parent function `can_load_uri`");
+
+            let mut error = std::ptr::null_mut();
+            let res = f(
+                self.obj()
+                    .unsafe_cast_ref::<crate::Formatter>()
+                    .to_glib_none()
+                    .0,
+                uri.to_glib_none().0,
+                &mut error,
+            );
+
+            if res == glib::ffi::GFALSE {
+                if error.is_null() {
+                    Err(glib::Error::new(
+                        gst::CoreError::Failed,
+                        "Can load uri failed",
+                    ))
+                } else {
+                    Err(from_glib_full(error))
+                }
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    fn parent_load_from_uri(
+        &self,
+        timeline: &crate::Timeline,
+        uri: &str,
+    ) -> Result<(), glib::Error> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GESFormatterClass;
+
+            let f = (*parent_class)
+                .load_from_uri
+                .expect("Missing parent function `load_from_uri`");
+
+            let mut error = std::ptr::null_mut();
+            let res = f(
+                self.obj()
+                    .unsafe_cast_ref::<crate::Formatter>()
+                    .to_glib_none()
+                    .0,
+                timeline
+                    .unsafe_cast_ref::<crate::Timeline>()
+                    .to_glib_none()
+                    .0,
+                uri.to_glib_none().0,
+                &mut error,
+            );
+
+            if res == glib::ffi::GFALSE {
+                if error.is_null() {
+                    Err(glib::Error::new(
+                        gst::CoreError::Failed,
+                        "Load from uri failed",
+                    ))
+                } else {
+                    Err(from_glib_full(error))
+                }
+            } else {
+                Ok(())
+            }
+        }
+    }
+    fn parent_save_to_uri(
+        &self,
+        timeline: &crate::Timeline,
+        uri: &str,
+        overwrite: bool,
+    ) -> Result<(), glib::Error> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *mut ffi::GESFormatterClass;
+
+            let f = (*parent_class)
+                .save_to_uri
+                .expect("Missing parent function `save_to_uri`");
+
+            let mut error = std::ptr::null_mut();
+            let res = f(
+                self.obj()
+                    .unsafe_cast_ref::<crate::Formatter>()
+                    .to_glib_none()
+                    .0,
+                timeline
+                    .unsafe_cast_ref::<crate::Timeline>()
+                    .to_glib_none()
+                    .0,
+                uri.to_glib_none().0,
+                overwrite.into_glib(),
+                &mut error,
+            );
+
+            if res == glib::ffi::GFALSE {
+                if error.is_null() {
+                    Err(glib::Error::new(
+                        gst::CoreError::Failed,
+                        "Save to uri failed",
+                    ))
+                } else {
+                    Err(from_glib_full(error))
+                }
+            } else {
+                Ok(())
+            }
+        }
+    }
+}
+
+unsafe impl<T: FormatterImpl> IsSubclassable<T> for Formatter {
+    fn class_init(klass: &mut glib::Class<Self>) {
+        Self::parent_class_init::<T>(klass);
+        let klass = klass.as_mut();
+        klass.can_load_uri = Some(formatter_can_load_uri::<T>);
+        klass.load_from_uri = Some(formatter_load_from_uri::<T>);
+        klass.save_to_uri = Some(formatter_save_to_uri::<T>);
+    }
+}
+
+unsafe extern "C" fn formatter_can_load_uri<T: FormatterImpl>(
+    ptr: *mut ffi::GESFormatter,
+    uri: *const libc::c_char,
+    error: *mut *mut glib::ffi::GError,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+
+    match imp.can_load_uri(glib::GString::from_glib_borrow(uri).as_str()) {
+        Err(err) => {
+            if !error.is_null() {
+                *error = err.into_glib_ptr();
+            }
+
+            glib::ffi::GFALSE
+        }
+        Ok(_) => glib::ffi::GTRUE,
+    }
+}
+
+unsafe extern "C" fn formatter_load_from_uri<T: FormatterImpl>(
+    ptr: *mut ffi::GESFormatter,
+    timeline: *mut ffi::GESTimeline,
+    uri: *const libc::c_char,
+    error: *mut *mut glib::ffi::GError,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let timeline = from_glib_borrow(timeline);
+
+    match imp.load_from_uri(&timeline, glib::GString::from_glib_borrow(uri).as_str()) {
+        Err(err) => {
+            if !error.is_null() {
+                *error = err.into_glib_ptr();
+            }
+
+            glib::ffi::GFALSE
+        }
+        Ok(_) => glib::ffi::GTRUE,
+    }
+}
+
+unsafe extern "C" fn formatter_save_to_uri<T: FormatterImpl>(
+    ptr: *mut ffi::GESFormatter,
+    timeline: *mut ffi::GESTimeline,
+    uri: *const libc::c_char,
+    overwrite: glib::ffi::gboolean,
+    error: *mut *mut glib::ffi::GError,
+) -> glib::ffi::gboolean {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.imp();
+    let timeline = from_glib_borrow(timeline);
+
+    match imp.save_to_uri(
+        &timeline,
+        glib::GString::from_glib_borrow(uri).as_str(),
+        from_glib(overwrite),
+    ) {
+        Err(err) => {
+            if !error.is_null() {
+                *error = err.into_glib_ptr();
+            }
+
+            glib::ffi::GFALSE
+        }
+        Ok(_) => glib::ffi::GTRUE,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Formatter;
+
+    pub mod imp {
+        use super::*;
+
+        #[derive(Default)]
+        pub struct SimpleFormatter;
+
+        #[glib::object_subclass]
+        impl ObjectSubclass for SimpleFormatter {
+            const NAME: &'static str = "SimpleFormatter";
+            type Type = super::SimpleFormatter;
+            type ParentType = Formatter;
+        }
+        impl ObjectImpl for SimpleFormatter {}
+        impl FormatterImpl for SimpleFormatter {
+            fn can_load_uri(&self, uri: &str) -> Result<(), glib::Error> {
+                if uri.starts_with("ges:test") {
+                    Ok(())
+                } else {
+                    self.parent_can_load_uri(uri)
+                }
+            }
+
+            fn load_from_uri(
+                &self,
+                timeline: &crate::Timeline,
+                _uri: &str,
+            ) -> Result<(), glib::Error> {
+                timeline.append_layer();
+
+                Ok(())
+            }
+
+            fn save_to_uri(
+                &self,
+                timeline: &crate::Timeline,
+                uri: &str,
+                _overwrite: bool,
+            ) -> Result<(), glib::Error> {
+                unsafe { timeline.set_data("saved", uri.to_string()) };
+
+                Ok(())
+            }
+        }
+    }
+
+    glib::wrapper! {
+        pub struct SimpleFormatter(ObjectSubclass<imp::SimpleFormatter>) @extends Formatter, gst::Object;
+    }
+
+    impl SimpleFormatter {
+        pub fn new() -> Self {
+            glib::Object::builder().build()
+        }
+    }
+
+    impl Default for SimpleFormatter {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+
+    #[test]
+    fn test_formatter_subclass() {
+        crate::init().unwrap();
+
+        let formatter = SimpleFormatter::new();
+        formatter
+            .can_load_uri("ges:test:")
+            .expect("We can load anything...");
+
+        assert!(formatter.can_load_uri("nottest").is_err());
+
+        let timeline = crate::Timeline::new();
+        assert_eq!(timeline.layers().len(), 0);
+        #[allow(deprecated)]
+        formatter
+            .load_from_uri(&timeline, "test")
+            .expect("We can load anything...");
+        assert_eq!(timeline.layers().len(), 1);
+
+        unsafe {
+            assert_eq!(timeline.data::<Option<String>>("saved"), None);
+        }
+        #[allow(deprecated)]
+        formatter
+            .save_to_uri(&timeline, "test", false)
+            .expect("We can save anything...");
+        unsafe {
+            assert_eq!(
+                timeline.data::<String>("saved").unwrap().as_ref(),
+                &"test".to_string()
+            );
+        }
+
+        Formatter::register(
+            SimpleFormatter::static_type(),
+            "SimpleFormatter",
+            None,
+            None,
+            None,
+            1.0,
+            gst::Rank::Primary,
+        );
+
+        let proj = crate::Project::new(Some("ges:test:"));
+        let timeline = proj
+            .extract()
+            .unwrap()
+            .downcast::<crate::Timeline>()
+            .unwrap();
+        assert_eq!(timeline.layers().len(), 1);
+
+        let proj = crate::Project::new(Some("ges:notest:"));
+        assert!(proj.extract().is_err());
+    }
+}
diff --git a/gstreamer-editing-services/src/subclass/mod.rs b/gstreamer-editing-services/src/subclass/mod.rs
new file mode 100644
index 000000000..8c644bed6
--- /dev/null
+++ b/gstreamer-editing-services/src/subclass/mod.rs
@@ -0,0 +1,13 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+#![allow(clippy::cast_ptr_alignment)]
+
+mod formatter;
+
+pub mod prelude {
+    #[doc(hidden)]
+    pub use glib::subclass::prelude::*;
+    pub use gst::subclass::prelude::*;
+
+    pub use super::formatter::{FormatterImpl, FormatterImplExt};
+}