media: Opus support for WebM in Media Source

media/base/audio_decoder_config.h

Index: media/base/audio_decoder_config.h
diff --git a/media/base/audio_decoder_config.h b/media/base/audio_decoder_config.h
index 1c61e70c3adba554c50a83d8f63e6f4208fc0296..77ba996f357f48c411a5b30bf7ec05e9cc4db106 100644
--- a/media/base/audio_decoder_config.h
+++ b/media/base/audio_decoder_config.h
@@ -80,6 +80,12 @@ class MEDIA_EXPORT AudioDecoderConfig {
   int samples_per_second() const { return samples_per_second_; }
   SampleFormat sample_format() const { return sample_format_; }
   int bytes_per_frame() const { return bytes_per_frame_; }
+  int64 seek_pre_roll() const { return seek_pre_roll_; }

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

nit: Use base::TimeDelta for this and the codec_delay since these fields
represent time. Since Opus only uses 48kHz we should be able to get the rounding
to microseconds to work out ok in all cases.

Another option is to specify these in terms of samples instead so that
conversions don't have to be done in the decoders. If you go the samples round,
use int instead and signal an error if we encounter a value in the file that
would overflow an int.

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

Done.

+  void set_seek_pre_roll(int64 seek_pre_roll) {

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

nit: These should be set in Initialize() and the constructor like all other
values.

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

Done.

+    seek_pre_roll_ = seek_pre_roll;
+  }
+  int64 codec_delay() const { return codec_delay_; }
+  void set_codec_delay(int64 codec_delay) { codec_delay_ = codec_delay; }
 
   // Optional byte data required to initialize audio decoders such as Vorbis
   // codebooks.
@@ -103,6 +109,15 @@ class MEDIA_EXPORT AudioDecoderConfig {
   std::vector<uint8> extra_data_;
   bool is_encrypted_;
 
+  // |seek_pre_roll_| is the duration in nanoseconds of the data that the
+  // decoder must decode before the decoded data is valid.
+  int64 seek_pre_roll_;
+
+  // |codec_delay_| is the overall delay overhead in nanoseconds added by the
+  // codec while encoding. This value should be subtracted from each block's
+  // timestamp to get the actual timestamp.
+  int64 codec_delay_;
+
   // Not using DISALLOW_COPY_AND_ASSIGN here intentionally to allow the compiler
   // generated copy constructor and assignment operator. Since the extra data is
   // typically small, the performance impact is minimal.