Support (E)AC3 passthrough

media/base/audio_bus.h

Index: media/base/audio_bus.h
diff --git a/media/base/audio_bus.h b/media/base/audio_bus.h
index 6d381ccac3daa3c9325fb9d4af99259e4cef3825..3610be806241696d1249b644565dab45045cdc07 100644
--- a/media/base/audio_bus.h
+++ b/media/base/audio_bus.h
@@ -72,6 +72,12 @@ class MEDIA_EXPORT AudioBus {
   void SetChannelData(int channel, float* data);
   void set_frames(int frames);
 
+  int data_size() const { return data_size_; }
+  void set_data_size(int data_size);

[DaleCurtis, 2016/11/01 23:05:13]

hacker_style() methods must be inline; I know we have some on here that aren't,
but don't add more. But that said, why are these changes necessary? Last we
discussed the RAW formats are all CBR, so you should be able to just construct a
single channel AudioBus with frames/4 size (1 byte vs float). Then you shouldn't
need to modify this class at all.

[AndyWu, 2016/11/04 18:04:24]

Thanks, I fixed hacker_style() methods.

Last time you pointed out that both AC3 and EAC3 are CBR. However, there are
more RAW formats:
https://developer.android.com/reference/android/media/AudioFormat.html
DTS-HD MA is VBR:
http://www.audiogurus.com/learn/electronics/dts-hd-master-audio/186
Do we really want to support CBR only?

One question, how to get "audio bit rate" in AudioRendererImpl::Initialize()?
That would be the key if we want to support CBR only and keep changes minimum.

+
+  int is_raw_format() const { return is_raw_format_; }
+  void set_is_raw_format(bool is_raw_format);
+
   // Overwrites the sample values stored in this AudioBus instance with values
   // from a given interleaved |source_buffer| with expected layout
   // [ch0, ch1, ..., chN, ch0, ch1, ...] and sample values in the format
@@ -209,6 +215,8 @@ class MEDIA_EXPORT AudioBus {
 
   // Contiguous block of channel memory.
   std::unique_ptr<float, base::AlignedFreeDeleter> data_;
+  int data_size_;
+  bool is_raw_format_;
 
   // One float pointer per channel pointing to a contiguous block of memory for
   // that channel. If the memory is owned by this instance, this will