Add support for channel transforms.

media/base/channel_layout.cc

Index: media/base/channel_layout.cc
diff --git a/media/base/channel_layout.cc b/media/base/channel_layout.cc
index 7c2d2e5b9b7038c90955558516e8446f93ff1c8b..2efd2042d7c69ea14c17ac5bd93b1b73b04a76f3 100644
--- a/media/base/channel_layout.cc
+++ b/media/base/channel_layout.cc
@@ -26,7 +26,8 @@ static const int kLayoutToChannels[] = {
     7,   // CHANNEL_LAYOUT_7POINT0
     8,   // CHANNEL_LAYOUT_7POINT1
     8,   // CHANNEL_LAYOUT_7POINT1_WIDE
-    2};  // CHANNEL_LAYOUT_STEREO_DOWNMIX
+    2,   // CHANNEL_LAYOUT_STEREO_DOWNMIX
+};
 
 // The channel orderings for each layout as specified by FFmpeg.  Each value
 // represents the index of each channel in each layout.  Values of -1 mean the
@@ -35,61 +36,61 @@ static const int kLayoutToChannels[] = {
 // the order is L, R, C, LFE, LS, RS), so
 // kChannelOrderings[CHANNEL_LAYOUT_5POINT1][SIDE_LEFT] = 4;
 static const int kChannelOrderings[CHANNEL_LAYOUT_MAX][CHANNELS_MAX] = {
-  // FL | FR | FC | LFE | BL | BR | FLofC | FRofC | BC | SL | SR | StL | StR
+    // FL | FR | FC | LFE | BL | BR | FLofC | FRofC | BC | SL | SR
 
-  // CHANNEL_LAYOUT_NONE
-  {  -1 , -1 , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_NONE
+    {  -1 , -1 , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_UNSUPPORTED
-  {  -1 , -1 , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_UNSUPPORTED
+    {  -1 , -1 , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_MONO
-  {  -1 , -1 , 0  , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_MONO
+    {  -1 , -1 , 0  , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_STEREO
-  {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_STEREO
+    {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_2_1
-  {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , 2  , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_2_1
+    {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , 2  , -1 , -1 },
 
-  // CHANNEL_LAYOUT_SURROUND
-  {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_SURROUND
+    {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_4POINT0
-  {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , 3  , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_4POINT0
+    {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , 3  , -1 , -1 },
 
-  // CHANNEL_LAYOUT_2_2
-  {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , -1 , 2  , 3  , -1  , -1 },
+    // CHANNEL_LAYOUT_2_2
+    {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , -1 , 2  ,  3 },
 
-  // CHANNEL_LAYOUT_QUAD
-  {  0  , 1  , -1 , -1  , 2  , 3  , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_QUAD
+    {  0  , 1  , -1 , -1  , 2  , 3  , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_5POINT0
-  {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , -1 , 3  , 4  , -1  , -1 },
+    // CHANNEL_LAYOUT_5POINT0
+    {  0  , 1  , 2  , -1  , -1 , -1 , -1    , -1    , -1 , 3  ,  4 },
 
-  // CHANNEL_LAYOUT_5POINT1
-  {  0  , 1  , 2  , 3   , -1 , -1 , -1    , -1    , -1 , 4  , 5  , -1  , -1 },
+    // CHANNEL_LAYOUT_5POINT1
+    {  0  , 1  , 2  , 3   , -1 , -1 , -1    , -1    , -1 , 4  ,  5 },
 
-  // CHANNEL_LAYOUT_5POINT0_BACK
-  {  0  , 1  , 2  , -1  , 3  , 4  , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_5POINT0_BACK
+    {  0  , 1  , 2  , -1  , 3  , 4  , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_5POINT1_BACK
-  {  0  , 1  , 2  , 3   , 4  , 5  , -1    , -1    , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_5POINT1_BACK
+    {  0  , 1  , 2  , 3   , 4  , 5  , -1    , -1    , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_7POINT0
-  {  0  , 1  , 2  , -1  , 5  , 6  , -1    , -1    , -1 , 3  , 4  , -1  , -1 },
+    // CHANNEL_LAYOUT_7POINT0
+    {  0  , 1  , 2  , -1  , 5  , 6  , -1    , -1    , -1 , 3  ,  4 },
 
-  // CHANNEL_LAYOUT_7POINT1
-  {  0  , 1  , 2  , 3   , 6  , 7  , -1    , -1    , -1 , 4  , 5  , -1  , -1 },
+    // CHANNEL_LAYOUT_7POINT1
+    {  0  , 1  , 2  , 3   , 6  , 7  , -1    , -1    , -1 , 4  ,  5 },
 
-  // CHANNEL_LAYOUT_7POINT1_WIDE
-  {  0  , 1  , 2  , 3   , 4  , 5  , 6     , 7     , -1 , -1 , -1 , -1  , -1 },
+    // CHANNEL_LAYOUT_7POINT1_WIDE
+    {  0  , 1  , 2  , 3   , 4  , 5  , 6     , 7     , -1 , -1 , -1 },
 
-  // CHANNEL_LAYOUT_STEREO_DOWNMIX
-  {  -1 , -1 , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 , 0   , 1  },
+    // CHANNEL_LAYOUT_STEREO_DOWNMIX
+    {  0  , 1  , -1 , -1  , -1 , -1 , -1    , -1    , -1 , -1 , -1 },
 
-  // FL | FR | FC | LFE | BL | BR | FLofC | FRofC | BC | SL | SR | StL | StR
-  };
+    // FL | FR | FC | LFE | BL | BR | FLofC | FRofC | BC | SL | SR
+};
 
 int ChannelLayoutToChannelCount(ChannelLayout layout) {
   DCHECK_LT(static_cast<size_t>(layout), arraysize(kLayoutToChannels));