diff --git a/audio/src/decoder.rs b/audio/src/decoder.rs
index d2e443c3..17bedfd6 100644
--- a/audio/src/decoder.rs
+++ b/audio/src/decoder.rs
@@ -2,7 +2,7 @@ use std::boxed::FnBox;
 use std::sync::Mutex;
 
 pub struct AudioDecoderCallbacks {
-    pub eos: Mutex<Option<Box<FnBox() + Send + 'static>>>,
+    pub eos: Mutex<Option<Box<FnBox(u32) + Send + 'static>>>,
     pub error: Mutex<Option<Box<FnBox() + Send + 'static>>>,
     pub progress: Option<Box<Fn(Box<AsRef<[f32]>>) + Send + Sync + 'static>>,
 }
@@ -16,11 +16,11 @@ impl AudioDecoderCallbacks {
         }
     }
 
-    pub fn eos(&self) {
+    pub fn eos(&self, channels: u32) {
         let eos = self.eos.lock().unwrap().take();
         match eos {
             None => return,
-            Some(callback) => callback(),
+            Some(callback) => callback(channels),
         };
     }
 
@@ -44,13 +44,13 @@ unsafe impl Send for AudioDecoderCallbacks {}
 unsafe impl Sync for AudioDecoderCallbacks {}
 
 pub struct AudioDecoderCallbacksBuilder {
-    eos: Option<Box<FnBox() + Send + 'static>>,
+    eos: Option<Box<FnBox(u32) + Send + 'static>>,
     error: Option<Box<FnBox() + Send + 'static>>,
     progress: Option<Box<Fn(Box<AsRef<[f32]>>) + Send + Sync + 'static>>,
 }
 
 impl AudioDecoderCallbacksBuilder {
-    pub fn eos<F: FnOnce() + Send + 'static>(self, eos: F) -> Self {
+    pub fn eos<F: FnOnce(u32) + Send + 'static>(self, eos: F) -> Self {
         Self {
             eos: Some(Box::new(eos)),
             ..self
@@ -82,14 +82,12 @@ impl AudioDecoderCallbacksBuilder {
 
 pub struct AudioDecoderOptions {
     pub sample_rate: f32,
-    pub channels: u32,
 }
 
 impl Default for AudioDecoderOptions {
     fn default() -> Self {
         AudioDecoderOptions {
             sample_rate: 44100.,
-            channels: 1,
         }
     }
 }
diff --git a/backends/gstreamer/src/audio_decoder.rs b/backends/gstreamer/src/audio_decoder.rs
index ea131d1d..70dbb309 100644
--- a/backends/gstreamer/src/audio_decoder.rs
+++ b/backends/gstreamer/src/audio_decoder.rs
@@ -76,11 +76,11 @@ impl AudioDecoder for GStreamerAudioDecoder {
             let pipeline = &pipeline_;
             let callbacks = &callbacks_;
 
-            let (is_audio, _) = {
+            let (is_audio, caps) = {
                 let media_type = src_pad.get_current_caps().and_then(|caps| {
                     caps.get_structure(0).map(|s| {
                         let name = s.get_name();
-                        (name.starts_with("audio/"), name.starts_with("video/"))
+                        (name.starts_with("audio/"), caps.clone())
                     })
                 });
 
@@ -103,12 +103,15 @@ impl AudioDecoder for GStreamerAudioDecoder {
                 let resample = gst::ElementFactory::make("audioresample", None).ok_or(())?;
                 let sink = gst::ElementFactory::make("appsink", None).ok_or(())?;
                 let appsink = sink.clone().dynamic_cast::<AppSink>().map_err(|_| ())?;
-                sink.set_property("sync", &false.to_value()).map_err(|_| ())?;
+                sink.set_property("sync", &false.to_value())
+                    .map_err(|_| ())?;
 
+                let sample_audio_info = gst_audio::AudioInfo::from_caps(&caps).ok_or(())?;
+                let channels = sample_audio_info.channels();
                 let audio_info = gst_audio::AudioInfo::new(
                     gst_audio::AUDIO_FORMAT_F32,
                     options.sample_rate as u32,
-                    options.channels,
+                    channels,
                 ).build()
                     .ok_or(())?;
                 appsink.set_caps(&audio_info.to_caps().unwrap());
@@ -149,7 +152,7 @@ impl AudioDecoder for GStreamerAudioDecoder {
                             gst::FlowReturn::Ok
                         })
                         .eos(move |_| {
-                            callbacks__.eos();
+                            callbacks__.eos(channels);
                             let _ = pipeline__.set_state(gst::State::Null);
                         })
                         .build(),
diff --git a/examples/audio_decoder.rs b/examples/audio_decoder.rs
index cf2417a5..bd472a01 100644
--- a/examples/audio_decoder.rs
+++ b/examples/audio_decoder.rs
@@ -26,8 +26,8 @@ fn run_example(servo_media: Arc<ServoMedia>) {
     let progress = decoded_audio.clone();
     let (sender, receiver) = mpsc::channel();
     let callbacks = AudioDecoderCallbacks::new()
-        .eos(move || {
-            sender.send(()).unwrap();
+        .eos(move |channels| {
+            sender.send(channels).unwrap();
         })
         .error(|| {
             eprintln!("Error decoding audio");
@@ -41,8 +41,8 @@ fn run_example(servo_media: Arc<ServoMedia>) {
         .build();
     context.decode_audio_data(bytes.to_vec(), callbacks);
     println!("Decoding audio");
-    receiver.recv().unwrap();
-    println!("Audio decoded");
+    let channels = receiver.recv().unwrap();
+    println!("Audio decoded. Channels {}", channels);
     let buffer_source =
         context.create_node(AudioNodeInit::AudioBufferSourceNode(Default::default()));
     let dest = context.dest_node();