media: Add support for playback of VP8 Alpha video streams

media/base/video_util.h

 // Copyright (c) 2012 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_VIDEO_UTIL_H_
 #define MEDIA_BASE_VIDEO_UTIL_H_
 
 #include "base/basictypes.h"
 #include "media/base/media_export.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace media {
 
 class VideoFrame;
 
 // Computes the size of |visible_size| for a given aspect ratio.
 MEDIA_EXPORT gfx::Size GetNaturalSize(const gfx::Size& visible_size,
                                       int aspect_ratio_numerator,
                                       int aspect_ratio_denominator);
 
-// Copies a plane of YUV source into a VideoFrame object, taking into account
+// Copies a plane of YUV(A) source into a VideoFrame object, taking into account
 // source and destinations dimensions.
 //
 // NOTE: rows is *not* the same as height!
 MEDIA_EXPORT void CopyYPlane(const uint8* source, int stride, int rows,
                              VideoFrame* frame);
 MEDIA_EXPORT void CopyUPlane(const uint8* source, int stride, int rows,
                              VideoFrame* frame);
 MEDIA_EXPORT void CopyVPlane(const uint8* source, int stride, int rows,
                              VideoFrame* frame);
+MEDIA_EXPORT void CopyAPlane(const uint8* source, int stride, int rows,
+                             VideoFrame* frame);
+// Sets A Plane values to be completely opaque (all 255's)

[scherkus (not reviewing), 2013/04/04 00:36:17]

nit: add blank line before // comments

nit: "A Plane" -> "alpha plane"

[vignesh, 2013/04/04 18:17:52]

Done.

+MEDIA_EXPORT void MakeOpaqueAPlane(int stride, int rows, VideoFrame* frame);
 // |plane| is one of VideoFrame::kYPlane, VideoFrame::kUPlane,

[scherkus (not reviewing), 2013/04/04 00:36:17]

nit: add blank line before // 

[vignesh, 2013/04/04 18:17:52]

Done.

-// or VideoFrame::kVPlane.
+// VideoFrame::kVPlane or VideoFrame::kAPlane
 MEDIA_EXPORT void CopyPlane(size_t plane, const uint8* source, int stride,
                             int rows, VideoFrame* frame);
 
 
 // Fills |frame| containing YUV data to the given color values.
 MEDIA_EXPORT void FillYUV(VideoFrame* frame, uint8 y, uint8 u, uint8 v);
 
 // Creates a border in |frame| such that all pixels outside of
 // |view_area| are black. The size and position of |view_area|
 // must be even to align correctly with the color planes.
@@ skipping 29 matching lines @@
 // Copy an RGB bitmap into the specified |region_in_frame| of a YUV video frame.
 // Fills the regions outside |region_in_frame| with black.
 MEDIA_EXPORT void CopyRGBToVideoFrame(const uint8* source,
                                       int stride,
                                       const gfx::Rect& region_in_frame,
                                       VideoFrame* frame);
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_UTIL_H_