Support (E)AC3 passthrough

media/base/audio_bus.cc

Index: media/base/audio_bus.cc
diff --git a/media/base/audio_bus.cc b/media/base/audio_bus.cc
index 31e9e4f49cc215448cd95b60858d584a2b651370..1daa6a3712ace29c0c0ecf8f9a7c7b79170b3195 100644
--- a/media/base/audio_bus.cc
+++ b/media/base/audio_bus.cc
@@ -62,7 +62,9 @@ void AudioBus::CheckOverflow(int start_frame, int frames, int total_frames) {
 }
 
 AudioBus::AudioBus(int channels, int frames)
-    : frames_(frames),
+    : data_size_(0),
+      is_bitstream_format_(false),
+      frames_(frames),
       can_set_channel_data_(false) {
   ValidateConfig(channels, frames_);
 
@@ -76,7 +78,9 @@ AudioBus::AudioBus(int channels, int frames)
 }
 
 AudioBus::AudioBus(int channels, int frames, float* data)
-    : frames_(frames),
+    : data_size_(0),
+      is_bitstream_format_(false),
+      frames_(frames),
       can_set_channel_data_(false) {
   // Since |data| may have come from an external source, ensure it's valid.
   CHECK(data);
@@ -89,7 +93,9 @@ AudioBus::AudioBus(int channels, int frames, float* data)
 }
 
 AudioBus::AudioBus(int frames, const std::vector<float*>& channel_data)
-    : channel_data_(channel_data),
+    : data_size_(0),
+      is_bitstream_format_(false),
+      channel_data_(channel_data),
       frames_(frames),
       can_set_channel_data_(false) {
   ValidateConfig(
@@ -101,7 +107,9 @@ AudioBus::AudioBus(int frames, const std::vector<float*>& channel_data)
 }
 
 AudioBus::AudioBus(int channels)
-    : channel_data_(channels),
+    : data_size_(0),
+      is_bitstream_format_(false),
+      channel_data_(channels),
       frames_(0),
       can_set_channel_data_(true) {
   CHECK_GT(channels, 0);
@@ -158,8 +166,10 @@ void AudioBus::SetChannelData(int channel, float* data) {
 }
 
 void AudioBus::set_frames(int frames) {
-  CHECK(can_set_channel_data_);
-  ValidateConfig(static_cast<int>(channel_data_.size()), frames);
+  if (!is_bitstream_format()) {

[DaleCurtis, 2017/06/15 21:46:32]

Why? Just change to CHECK(can_set_channel_data_ || is_bitstream_format())?

[AndyWu, 2017/08/02 01:43:40]

Done.

+    CHECK(can_set_channel_data_);
+    ValidateConfig(static_cast<int>(channel_data_.size()), frames);
+  }
   frames_ = frames;
 }
 
@@ -308,6 +318,14 @@ void AudioBus::ToInterleavedPartial(int start_frame,
 }
 
 void AudioBus::CopyTo(AudioBus* dest) const {
+  dest->set_is_bitstream_format(is_bitstream_format());

[DaleCurtis, 2017/06/15 21:46:32]

Move inside? I don't think we need to worry about switching between the two
buffers do we?

[AndyWu, 2017/08/02 01:43:40]

Not sure it's a good idea to assume the state of a parameter |dest|. I would
rather to ensure the state consistency.

+  if (is_bitstream_format()) {
+    dest->set_data_size(data_size());
+    dest->set_frames(frames());
+    memcpy(dest->channel(0), channel(0), data_size());
+    return;
+  }
+
   CopyPartialFramesTo(0, frames(), 0, dest);
 }