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

3 files changed, 93 insertions, 3 deletions

diff --git a/media/base/audio_decoder_config.h b/media/base/audio_decoder_config.h
index 791d2cd..e2c848d 100644
--- a/media/base/audio_decoder_config.h
+++ b/media/base/audio_decoder_config.h
@@ -5,17 +5,19 @@
 #ifndef MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
 #define MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
 
+#include "media/base/channel_layout.h"
+
 namespace media {
 
 struct AudioDecoderConfig {
-  AudioDecoderConfig(int bits, int channels, int rate)
+  AudioDecoderConfig(int bits, ChannelLayout layout, int rate)
       : bits_per_channel(bits),
-        channels_per_sample(channels),
+        channel_layout(layout),
         sample_rate(rate) {
   }
 
   int bits_per_channel;
-  int channels_per_sample;
+  ChannelLayout channel_layout;
   int sample_rate;
 };
 
diff --git a/media/base/channel_layout.cc b/media/base/channel_layout.cc
new file mode 100644
index 0000000..8e3da4f
--- /dev/null
+++ b/media/base/channel_layout.cc
@@ -0,0 +1,28 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/channel_layout.h"
+
+static const int kLayoutToChannels[] = {
+    0,   // CHANNEL_LAYOUT_NONE
+    0,   // CHANNEL_LAYOUT_UNSUPPORTED
+    1,   // CHANNEL_LAYOUT_MONO
+    2,   // CHANNEL_LAYOUT_STEREO
+    3,   // CHANNEL_LAYOUT_2_1
+    3,   // CHANNEL_LAYOUT_SURROUND
+    4,   // CHANNEL_LAYOUT_4POINT0
+    4,   // CHANNEL_LAYOUT_2_2
+    4,   // CHANNEL_LAYOUT_QUAD
+    5,   // CHANNEL_LAYOUT_5POINT0
+    6,   // CHANNEL_LAYOUT_5POINT1
+    5,   // CHANNEL_LAYOUT_5POINT0_BACK
+    6,   // CHANNEL_LAYOUT_5POINT1_BACK
+    7,   // CHANNEL_LAYOUT_7POINT0
+    8,   // CHANNEL_LAYOUT_7POINT1
+    8,   // CHANNEL_LAYOUT_7POINT1_WIDE
+    2};  // CHANNEL_LAYOUT_STEREO_DOWNMIX
+
+int ChannelLayoutToChannelCount(ChannelLayout layout) {
+  return kLayoutToChannels[layout];
+}
diff --git a/media/base/channel_layout.h b/media/base/channel_layout.h
new file mode 100644
index 0000000..b8e1204
--- /dev/null
+++ b/media/base/channel_layout.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_CHANNEL_LAYOUT_H_
+#define MEDIA_BASE_CHANNEL_LAYOUT_H_
+
+enum ChannelLayout {
+  CHANNEL_LAYOUT_NONE = 0,
+  CHANNEL_LAYOUT_UNSUPPORTED,
+
+  // Front C
+  CHANNEL_LAYOUT_MONO,
+
+  // Front L, Front R
+  CHANNEL_LAYOUT_STEREO,
+
+  // Front L, Front R, Back C
+  CHANNEL_LAYOUT_2_1,
+
+  // Front L, Front R, Front C
+  CHANNEL_LAYOUT_SURROUND,
+
+  // Front L, Front R, Front C, Back C
+  CHANNEL_LAYOUT_4POINT0,
+
+  // Front L, Front R, Side L, Side R
+  CHANNEL_LAYOUT_2_2,
+
+  // Front L, Front R, Back L, Back R
+  CHANNEL_LAYOUT_QUAD,
+
+  // Front L, Front R, Front C, Side L, Side R
+  CHANNEL_LAYOUT_5POINT0,
+
+  // Front L, Front R, Front C, Side L, Side R, LFE
+  CHANNEL_LAYOUT_5POINT1,
+
+  // Front L, Front R, Front C, Back L, Back R
+  CHANNEL_LAYOUT_5POINT0_BACK,
+
+  // Front L, Front R, Front C, Back L, Back R, LFE
+  CHANNEL_LAYOUT_5POINT1_BACK,
+
+  // Front L, Front R, Front C, Side L, Side R, Back L, Back R
+  CHANNEL_LAYOUT_7POINT0,
+
+  // Front L, Front R, Front C, Side L, Side R, LFE, Back L, Back R
+  CHANNEL_LAYOUT_7POINT1,
+
+  // Front L, Front R, Front C, Back L, Back R, LFE, Front LofC, Front RofC
+  CHANNEL_LAYOUT_7POINT1_WIDE,
+
+  // Stereo L, Stereo R
+  CHANNEL_LAYOUT_STEREO_DOWNMIX
+};
+
+int ChannelLayoutToChannelCount(ChannelLayout layout);
+
+#endif  // MEDIA_BASE_CHANNEL_LAYOUT_H_