Description:

This patch gets the channel layout for surround sound channel order from ffmpeg and stores it so that chromium will be able to re-order the channels for various sound cards and OSes later.

- AudioParameters gets a new field (channel_layout).
- channel_layout.h stores an enum that we will use in chromium for channel values.
- ffmpeg_common.h gets a new method for mapping the channel layout received from ffmpeg to an internal chromium enum value.


BUG=None (though storing the channel order should help us solve some other bugs soon)
TEST=media_unittests


Review URL: http://codereview.chromium.org/6930039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85541 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 52 insertions, 0 deletions

diff --git a/media/ffmpeg/ffmpeg_common.cc b/media/ffmpeg/ffmpeg_common.cc
index 9f5eaeb..dedc40c 100644
--- a/media/ffmpeg/ffmpeg_common.cc
+++ b/media/ffmpeg/ffmpeg_common.cc
@@ -61,6 +61,51 @@ CodecID VideoCodecToCodecID(VideoCodec video_codec) {
   return CODEC_ID_NONE;
 }
 
+ChannelLayout ChannelLayoutToChromeChannelLayout(int64_t layout,
+                                                 int channels) {
+  switch (layout) {
+    case CH_LAYOUT_MONO:
+      return CHANNEL_LAYOUT_MONO;
+    case CH_LAYOUT_STEREO:
+      return CHANNEL_LAYOUT_STEREO;
+    case CH_LAYOUT_2_1:
+      return CHANNEL_LAYOUT_2_1;
+    case CH_LAYOUT_SURROUND:
+      return CHANNEL_LAYOUT_SURROUND;
+    case CH_LAYOUT_4POINT0:
+      return CHANNEL_LAYOUT_4POINT0;
+    case CH_LAYOUT_2_2:
+      return CHANNEL_LAYOUT_2_2;
+    case CH_LAYOUT_QUAD:
+      return CHANNEL_LAYOUT_QUAD;
+    case CH_LAYOUT_5POINT0:
+      return CHANNEL_LAYOUT_5POINT0;
+    case CH_LAYOUT_5POINT1:
+      return CHANNEL_LAYOUT_5POINT1;
+    case CH_LAYOUT_5POINT0_BACK:
+      return CHANNEL_LAYOUT_5POINT0_BACK;
+    case CH_LAYOUT_5POINT1_BACK:
+      return CHANNEL_LAYOUT_5POINT1_BACK;
+    case CH_LAYOUT_7POINT0:
+      return CHANNEL_LAYOUT_7POINT0;
+    case CH_LAYOUT_7POINT1:
+      return CHANNEL_LAYOUT_7POINT1;
+    case CH_LAYOUT_7POINT1_WIDE:
+      return CHANNEL_LAYOUT_7POINT1_WIDE;
+    case CH_LAYOUT_STEREO_DOWNMIX:
+      return CHANNEL_LAYOUT_STEREO_DOWNMIX;
+    default:
+      // FFmpeg channel_layout is 0 for .wav and .mp3.  We know mono and stereo
+      // from the number of channels, otherwise report errors.
+      if (channels == 1)
+        return CHANNEL_LAYOUT_MONO;
+      if (channels == 2)
+        return CHANNEL_LAYOUT_STEREO;
+      DLOG(WARNING) << "Unsupported/unencountered channel layout values";
+      return CHANNEL_LAYOUT_UNSUPPORTED;
+  }
+}
+
 base::TimeDelta GetFrameDuration(AVStream* stream) {
   AVRational time_base = { stream->r_frame_rate.den, stream->r_frame_rate.num };
   return ConvertFromTimeBase(time_base, 1);
diff --git a/media/ffmpeg/ffmpeg_common.h b/media/ffmpeg/ffmpeg_common.h
index 196b57e..3d39d52 100644
--- a/media/ffmpeg/ffmpeg_common.h
+++ b/media/ffmpeg/ffmpeg_common.h
@@ -11,6 +11,7 @@
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 #include "base/time.h"
+#include "media/base/channel_layout.h"
 #include "media/video/video_decode_engine.h"
 
 // Include FFmpeg header files.
@@ -66,6 +67,12 @@ int64 ConvertToTimeBase(const AVRational& time_base,
 VideoCodec CodecIDToVideoCodec(CodecID codec_id);
 CodecID VideoCodecToCodecID(VideoCodec video_codec);
 
+// Converts FFmpeg's channel layout to chrome's ChannelLayout.  |channels| can
+// be used when FFmpeg's channel layout is not informative in order to make a
+// good guess about the plausible channel layout based on number of channels.
+ChannelLayout ChannelLayoutToChromeChannelLayout(int64_t layout,
+                                                 int channels);
+
 // Calculates duration of one frame in the |stream| based on its frame rate.
 base::TimeDelta GetFrameDuration(AVStream* stream);