diff --git a/gstreamer-video/src/functions.rs b/gstreamer-video/src/functions.rs
new file mode 100644
index 000000000..7bff9d539
--- /dev/null
+++ b/gstreamer-video/src/functions.rs
@@ -0,0 +1,87 @@
+// Copyright (C) 2017 Sebastian Dröge <sebastian@centricular.com>
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use ffi;
+use gst_ffi;
+use glib_ffi;
+
+use gst;
+use glib;
+use glib::translate::{from_glib_full, from_glib_none, ToGlib, ToGlibPtr};
+
+use std::ptr;
+use std::mem;
+
+pub fn convert_sample(
+    sample: &gst::Sample,
+    caps: &gst::Caps,
+    timeout: gst::ClockTime,
+) -> Result<gst::Sample, glib::Error> {
+    unsafe {
+        let mut error = ptr::null_mut();
+        let ret = ffi::gst_video_convert_sample(
+            sample.to_glib_none().0,
+            caps.to_glib_none().0,
+            timeout.to_glib(),
+            &mut error,
+        );
+
+        if error.is_null() {
+            Ok(from_glib_full(ret))
+        } else {
+            Err(from_glib_full(error))
+        }
+    }
+}
+
+pub fn convert_sample_async<F>(
+    sample: &gst::Sample,
+    caps: &gst::Caps,
+    timeout: gst::ClockTime,
+    func: F,
+) where
+    F: FnOnce(Result<gst::Sample, glib::Error>) + Send + 'static,
+{
+    unsafe extern "C" fn convert_sample_async_trampoline<F>(
+        sample: *mut gst_ffi::GstSample,
+        error: *mut glib_ffi::GError,
+        user_data: glib_ffi::gpointer,
+    ) where
+        F: FnOnce(Result<gst::Sample, glib::Error>) + Send + 'static,
+    {
+        callback_guard!();
+        let callback: &mut Option<Box<F>> = mem::transmute(user_data);
+        let callback = callback.take().unwrap();
+
+        if error.is_null() {
+            callback(Ok(from_glib_none(sample)))
+        } else {
+            callback(Err(from_glib_none(error)))
+        }
+    }
+    unsafe extern "C" fn convert_sample_async_free<F>(user_data: glib_ffi::gpointer)
+    where
+        F: FnOnce(Result<gst::Sample, glib::Error>) + Send + 'static,
+    {
+        callback_guard!();
+        let _: Box<Option<Box<F>>> = Box::from_raw(user_data as *mut _);
+    }
+
+    unsafe {
+        let user_data: Box<Option<Box<F>>> = Box::new(Some(Box::new(func)));
+
+        ffi::gst_video_convert_sample_async(
+            sample.to_glib_none().0,
+            caps.to_glib_none().0,
+            timeout.to_glib(),
+            Some(convert_sample_async_trampoline::<F>),
+            Box::into_raw(user_data) as glib_ffi::gpointer,
+            Some(convert_sample_async_free::<F>),
+        );
+    }
+}
diff --git a/gstreamer-video/src/lib.rs b/gstreamer-video/src/lib.rs
index f08cea771..ff33a6c47 100644
--- a/gstreamer-video/src/lib.rs
+++ b/gstreamer-video/src/lib.rs
@@ -31,6 +31,12 @@ macro_rules! skip_assert_initialized {
     )
 }
 
+macro_rules! callback_guard {
+    () => (
+        let _guard = ::glib::CallbackGuard::new();
+    )
+}
+
 pub use glib::{Cast, Continue, Error, IsA, StaticType, ToValue, Type, TypedValue, Value};
 
 #[cfg_attr(feature = "cargo-clippy", allow(unreadable_literal))]
@@ -52,6 +58,8 @@ mod video_overlay;
 pub use video_overlay::VideoOverlayExtManual;
 mod video_event;
 pub use video_event::*;
+mod functions;
+pub use functions::*;
 
 // Re-export all the traits in a prelude module, so that applications
 // can always "use gst::prelude::*" without getting conflicts