cras_unified: set channel layout

Convert the channel layout value and set to created
cras_audio_format. This will allow CRAS to do correct
down mix and channel mapping.

BUG=214597
TEST=Build and deploy Chrome to Pixel, add debug log to CRAS,
play a 6-channel .wav file to verify the channel_layout is set.

Review URL: https://codereview.chromium.org/32543002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231677 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 33 insertions, 0 deletions

diff --git a/media/audio/cras/cras_unified.cc b/media/audio/cras/cras_unified.cc
index fe2c7b0..906f209 100644
--- a/media/audio/cras/cras_unified.cc
+++ b/media/audio/cras/cras_unified.cc
@@ -161,6 +161,23 @@ void CrasUnifiedStream::Close() {
 
 void CrasUnifiedStream::Start(AudioSourceCallback* callback) {
   CHECK(callback);
+
+  // Channel map to CRAS_CHANNEL, values in the same order of
+  // corresponding source in Chromium defined Channels.
+  static const int kChannelMap[] = {
+    CRAS_CH_FL,
+    CRAS_CH_FR,
+    CRAS_CH_FC,
+    CRAS_CH_LFE,
+    CRAS_CH_RL,
+    CRAS_CH_RR,
+    CRAS_CH_FLC,
+    CRAS_CH_FRC,
+    CRAS_CH_RC,
+    CRAS_CH_SL,
+    CRAS_CH_SR
+  };
+
   source_callback_ = callback;
 
   // Only start if we can enter the playing state.
@@ -179,6 +196,22 @@ void CrasUnifiedStream::Start(AudioSourceCallback* callback) {
     return;
   }
 
+  // Initialize channel layout to all -1 to indicate that none of
+  // the channels is set in the layout.
+  int8 layout[CRAS_CH_MAX] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 };
+
+  // Converts to CRAS defined channels. ChannelOrder will return -1
+  // for channels that does not present in params_.channel_layout().
+  for (size_t i = 0; i < arraysize(kChannelMap); ++i)
+    layout[kChannelMap[i]] = ChannelOrder(params_.channel_layout(),
+                                          static_cast<Channels>(i));
+
+  if (cras_audio_format_set_channel_layout(audio_format, layout)) {
+    LOG(WARNING) << "Error setting channel layout.";
+    callback->OnError(this);
+    return;
+  }
+
   cras_stream_params* stream_params = cras_client_unified_params_create(
       stream_direction_,
       params_.frames_per_buffer(),