media: Opus support for WebM in Media Source

media/webm/webm_audio_client.cc

Index: media/webm/webm_audio_client.cc
diff --git a/media/webm/webm_audio_client.cc b/media/webm/webm_audio_client.cc
index e52f44b4a9a7f33ee8bf8119b044999e4e4c8eee..3cec3fb10ed7df0d4109e545a946f3abc79fb879 100644
--- a/media/webm/webm_audio_client.cc
+++ b/media/webm/webm_audio_client.cc
@@ -26,12 +26,15 @@ void WebMAudioClient::Reset() {
 
 bool WebMAudioClient::InitializeConfig(
     const std::string& codec_id, const std::vector<uint8>& codec_private,
-    bool is_encrypted, AudioDecoderConfig* config) {
+    int64 seek_pre_roll, int64 codec_delay, bool is_encrypted,
+    AudioDecoderConfig* config) {
   DCHECK(config);
 
   AudioCodec audio_codec = kUnknownAudioCodec;
   if (codec_id == "A_VORBIS") {
     audio_codec = kCodecVorbis;
+  } else if (codec_id == "A_OPUS" || codec_id == "A_OPUS/EXPERIMENTAL") {

[acolwell GONE FROM CHROMIUM, 2013/08/28 20:44:47]

The spec only specifies A_OPUS. I'd prefer to force people to only use that
codec_id if they want to use their content w/ MediaSource.

[vignesh, 2013/08/29 21:37:31]

Right now ffmpeg puts A_OPUS/EXPERIMENTAL. I thought we can allow such files to
playback (for now atleast) and remove this later once Opus becomes stable.
Please let me know if you think otherwise and I can change this.

[acolwell GONE FROM CHROMIUM, 2013/09/03 20:14:01]

I have concerns that a large amount of content will be generated with the
/EXPERIMENTAL suffix and we will never be able to drop it. For example, it would
make me really sad if YouTube reencoded all the content w/ the
A_OPUS/EXPERIMENTAL form. Any idea why FFMPEG isn't committing to just using
A_OPUS at this point?

[vignesh, 2013/09/03 22:43:03]

I understand your concern. I will remove the Experimental suffix. 

As to why ffmpeg isn't committing to A_OPUS at this point, i am unsure. Anyway,
I am going to try and push ffmpeg to drop the suffix, because now that the
matroska opus spec is finalized, it does not make sense to have the suffix
anymore.

+    audio_codec = kCodecOpus;
   } else {
     MEDIA_LOG(log_cb_) << "Unsupported audio codec_id " << codec_id;
     return false;
@@ -63,8 +66,12 @@ bool WebMAudioClient::InitializeConfig(
   }
 
   config->Initialize(
-      audio_codec, kSampleFormatPlanarF32, channel_layout,
+      audio_codec,
+      (audio_codec == kCodecOpus) ? kSampleFormatS16 : kSampleFormatPlanarF32,
+      channel_layout,

[Tom Finegan, 2013/08/28 01:35:35]

Ditto on the question re unconditional S16 for Opus.

[vignesh, 2013/08/29 21:37:31]

Done.

       samples_per_second, extra_data, extra_data_size, is_encrypted, true);
+  config->set_seek_pre_roll(seek_pre_roll);
+  config->set_codec_delay(codec_delay);
   return config->IsValidConfig();
 }