Support Opus Ambisonics playback

content/renderer/media/audio_renderer_mixer_manager.cc

Index: content/renderer/media/audio_renderer_mixer_manager.cc
diff --git a/content/renderer/media/audio_renderer_mixer_manager.cc b/content/renderer/media/audio_renderer_mixer_manager.cc
index f22bdc3f6d7c94d38cff3ee3f6ac4e05466c47ac..03b5fe86820095cda9a96fcbf29f813243d0fa49 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.cc
+++ b/content/renderer/media/audio_renderer_mixer_manager.cc
@@ -70,10 +70,17 @@ media::AudioParameters GetMixerOutputParams(
 
   DCHECK_NE(output_buffer_size, 0);
 
+  // If the input has discrete channel layout, the hardware channel mapping is
+  // unknown. Default to the hardware channel layout instead. Any input
+  // channels beyond the hardware channel count will not be played out.
+  media::ChannelLayout channel_layout =
+      input_params.channel_layout() == media::CHANNEL_LAYOUT_DISCRETE
+          ? hardware_params.channel_layout()
+          : input_params.channel_layout();
+

[DaleCurtis, 2017/03/31 19:06:53]

Needs set_channels.

[flim-chromium, 2017/04/05 18:19:34]

I ended up removing this. 

   // Force to 16-bit output for now since we know that works everywhere;
   // ChromeOS does not support other bit depths.
-  media::AudioParameters params(input_params.format(),
-                                input_params.channel_layout(),
+  media::AudioParameters params(input_params.format(), channel_layout,
                                 output_sample_rate, 16, output_buffer_size);
 
   // Specify the latency info to be passed to the browser side.