Add Opus decode wrapper to media.

webkit/media/filter_helpers.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/media/filter_helpers.h"
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "media/base/filter_collection.h"
+#include "media/base/media_switches.h"
 #include "media/filters/decrypting_audio_decoder.h"
 #include "media/filters/decrypting_video_decoder.h"
 #include "media/filters/chunk_demuxer.h"
 #include "media/filters/dummy_demuxer.h"
 #include "media/filters/ffmpeg_audio_decoder.h"
 #include "media/filters/ffmpeg_demuxer.h"
 #include "media/filters/ffmpeg_video_decoder.h"
+#include "media/filters/opus_audio_decoder.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURL.h"
 #include "webkit/media/crypto/proxy_decryptor.h"
 #include "webkit/media/media_stream_client.h"
 
 namespace webkit_media {
 
 // Constructs and adds the default audio/video decoders to |filter_collection|.
 // Note that decoders in the |filter_collection| are ordered. The first
 // audio/video decoder in the |filter_collection| that supports the input
 // audio/video stream will be selected as the audio/video decoder in the media
 // pipeline. This is done by trying to initialize the decoder with the input
 // stream. Some decoder may only accept certain types of streams. For example,
 // DecryptingVideoDecoder only supports encrypted video stream.
 static void AddDefaultDecodersToCollection(
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     media::FilterCollection* filter_collection,
     ProxyDecryptor* proxy_decryptor) {
+
+  const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
+  if (cmd_line->HasSwitch(switches::kEnableVp9OpusPlayback)) {
+    scoped_refptr<media::OpusAudioDecoder> opus_audio_decoder =
+        new media::OpusAudioDecoder(message_loop);
+    filter_collection->GetAudioDecoders()->push_back(opus_audio_decoder);
+  }

[xhwang, 2012/12/14 08:41:48]

media pipeline tries each audio decoder in the order they are pushed until an
audio decoder that can decode certain input stream is found. since in most cases
audio is not opus (and I assume FFmpegAudioDecoder cannot decode opus?), can we
move this block to line 47?

[Tom Finegan, 2012/12/14 20:21:34]

Done.

+
   scoped_refptr<media::FFmpegAudioDecoder> ffmpeg_audio_decoder =
       new media::FFmpegAudioDecoder(message_loop);
   filter_collection->GetAudioDecoders()->push_back(ffmpeg_audio_decoder);
 
   if (proxy_decryptor) {
     scoped_refptr<media::DecryptingAudioDecoder> decrypting_audio_decoder =
         new media::DecryptingAudioDecoder(
             message_loop,
             base::Bind(&ProxyDecryptor::RequestDecryptorNotification,
                        base::Unretained(proxy_decryptor)));
@@ skipping 65 matching lines @@
     media::FilterCollection* filter_collection,
     ProxyDecryptor* proxy_decryptor) {
   filter_collection->SetDemuxer(new media::FFmpegDemuxer(
       message_loop, data_source));
 
   AddDefaultDecodersToCollection(message_loop, filter_collection,
                                  proxy_decryptor);
 }
 
 }  // webkit_media