Pass more detailed audio hardware configuration information to the renderer

media/audio/mac/audio_manager_mac.cc

Index: media/audio/mac/audio_manager_mac.cc
===================================================================
--- media/audio/mac/audio_manager_mac.cc	(revision 186233)
+++ media/audio/mac/audio_manager_mac.cc	(working copy)
@@ -336,7 +336,8 @@
 
 AudioParameters AudioManagerMac::GetPreferredOutputStreamParameters(
     const AudioParameters& input_params) {
-  ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
+  ChannelLayout channel_layout = CHANNEL_LAYOUT_UNSUPPORTED;
+  
   int input_channels = 0;
   if (input_params.IsValid()) {
     channel_layout = input_params.channel_layout();

[DaleCurtis, 2013/03/06 19:19:30]

Instead of doing this I think you should use FFmpegCommon::GuessChannelLayout()
(please move this function into the channel_layout.{cc,h} file when
CHANNEL_LAYOUT is NOT channel_layout_discrete. This will fix
http://crbug.com/169396 

[Chris Rogers, 2013/03/07 00:34:17]

I think I've changed it to be more in line with your thinking here.

@@ -352,10 +353,24 @@
     }
   }
 
-  return AudioParameters(
-      AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout, input_channels,
-      AUAudioOutputStream::HardwareSampleRate(), 16,
+  AudioParameters params(
+      AudioParameters::AUDIO_PCM_LOW_LATENCY,
+      channel_layout,
+      input_channels,
+      AUAudioOutputStream::HardwareSampleRate(),
+      16,
       kDefaultLowLatencyBufferSize);
+
+  if (channel_layout == CHANNEL_LAYOUT_UNSUPPORTED) {
+    int channels = 2;
+    int channels_per_frame;
+    AudioHardwareUnifiedStream::GetDefaultOutputChannels(
+      &channels, &channels_per_frame);

[DaleCurtis, 2013/03/06 19:19:30]

4 space indent.

[Chris Rogers, 2013/03/07 00:34:17]

Done.

+
+    params.SetDiscreteChannels(channels);
+  }
+  
+  return params;
 }
 
 void AudioManagerMac::CreateDeviceListener() {