Re-add AC3/EAC3 audio demuxing support

media/ffmpeg/ffmpeg_common.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 "media/ffmpeg/ffmpeg_common.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/sha1.h"
@@ skipping 49 matching lines @@
 int64 ConvertToTimeBase(const AVRational& time_base,
                         const base::TimeDelta& timestamp) {
   return av_rescale_q(timestamp.InMicroseconds(), kMicrosBase, time_base);
 }
 
 // Converts an FFmpeg audio codec ID into its corresponding supported codec id.
 static AudioCodec CodecIDToAudioCodec(AVCodecID codec_id) {
   switch (codec_id) {
     case AV_CODEC_ID_AAC:
       return kCodecAAC;
+#if defined(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
+    case AV_CODEC_ID_AC3:
+      return kCodecAC3;
+    case AV_CODEC_ID_EAC3:
+      return kCodecEAC3;
+#endif
     case AV_CODEC_ID_MP3:
       return kCodecMP3;
     case AV_CODEC_ID_VORBIS:
       return kCodecVorbis;
     case AV_CODEC_ID_PCM_U8:
     case AV_CODEC_ID_PCM_S16LE:
     case AV_CODEC_ID_PCM_S24LE:
     case AV_CODEC_ID_PCM_F32LE:
       return kCodecPCM;
     case AV_CODEC_ID_PCM_S16BE:
@@ skipping 206 matching lines @@
   return AV_SAMPLE_FMT_NONE;
 }
 
 bool AVCodecContextToAudioDecoderConfig(const AVCodecContext* codec_context,
                                         bool is_encrypted,
                                         AudioDecoderConfig* config) {
   DCHECK_EQ(codec_context->codec_type, AVMEDIA_TYPE_AUDIO);
 
   AudioCodec codec = CodecIDToAudioCodec(codec_context->codec_id);
 
+  // For AC3/EAC3, FFmpeg does not fill |sample_fmt|.
   SampleFormat sample_format =
-      AVSampleFormatToSampleFormat(codec_context->sample_fmt);
+      (codec == kCodecAC3 || codec == kCodecEAC3)
+          ? kSampleFormatS16
+          : AVSampleFormatToSampleFormat(codec_context->sample_fmt);
 
   ChannelLayout channel_layout = ChannelLayoutToChromeChannelLayout(
       codec_context->channel_layout, codec_context->channels);
 
   int sample_rate = codec_context->sample_rate;
   if (codec == kCodecOpus) {
     // |codec_context->sample_fmt| is not set by FFmpeg because Opus decoding is
     // not enabled in FFmpeg.  It doesn't matter what value is set here, so long
     // as it's valid, the true sample format is selected inside the decoder.
     sample_format = kSampleFormatF32;
@@ skipping 28 matching lines @@
                       codec_context->extradata + codec_context->extradata_size);
   }
   config->Initialize(codec,
                      sample_format,
                      channel_layout,
                      sample_rate,
                      extra_data,
                      is_encrypted,
                      seek_preroll,
                      codec_context->delay);
-
-  if (codec != kCodecOpus) {
+  if (codec != kCodecOpus && codec != kCodecAC3 && codec != kCodecEAC3) {
     DCHECK_EQ(av_get_bytes_per_sample(codec_context->sample_fmt) * 8,
               config->bits_per_channel());
   }
 
   return true;
 }
 
 bool AVStreamToAudioDecoderConfig(const AVStream* stream,
                                   AudioDecoderConfig* config) {
   bool is_encrypted = false;
@@ skipping 323 matching lines @@
 }
 
 int32_t HashCodecName(const char* codec_name) {
   // Use the first 32-bits from the SHA1 hash as the identifier.
   int32_t hash;
   memcpy(&hash, base::SHA1HashString(codec_name).substr(0, 4).c_str(), 4);
   return hash;
 }
 
 }  // namespace media