Provide a Chrome-owned buffer to FFmpeg for video decoding, instead of

media/base/video_frame.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_FRAME_H_
 #define MEDIA_BASE_VIDEO_FRAME_H_
 
 #include "base/callback.h"
 #include "base/md5.h"
 #include "media/base/buffers.h"
@@ skipping 20 matching lines @@
     INVALID = 0,  // Invalid format value.  Used for error reporting.
     RGB32 = 4,  // 32bpp RGB packed with extra byte 8:8:8
     YV12 = 6,  // 12bpp YVU planar 1x1 Y, 2x2 VU samples
     YV16 = 7,  // 16bpp YVU planar 1x1 Y, 2x1 VU samples
     EMPTY = 9,  // An empty frame.
     I420 = 11,  // 12bpp YVU planar 1x1 Y, 2x2 UV samples.
     NATIVE_TEXTURE = 12,  // Native texture.  Pixel-format agnostic.
   };
 
   // Creates a new frame in system memory with given parameters. Buffers for
-  // the frame are allocated but not initialized.
+  // the frame are allocated but not initialized. If given, alignment is a
+  // power of 2 number (in bytes) by which the horizontal and vertical buffer
+  // dimensions should be aligned during allocation.
+  static scoped_refptr<VideoFrame> CreateFrame(
+      Format format,
+      size_t width,
+      size_t height,
+      size_t alignment,
+      base::TimeDelta timestamp,
+      base::TimeDelta duration);
   static scoped_refptr<VideoFrame> CreateFrame(

[Ami GONE FROM CHROMIUM, 2012/06/15 06:53:30]

Chromium (and google) style guides prohibit function overloading like this.  You
really do have to go around and update all callers (which shouldn't be very many
at all for this and the next functions).

       Format format,
       size_t width,
       size_t height,
       base::TimeDelta timestamp,
-      base::TimeDelta duration);
+      base::TimeDelta duration) {
+    return CreateFrame(format, width, height, 1, timestamp, duration);
+  }
 
   // Call prior to CreateFrame to ensure validity of frame configuration. Called
   // automatically by VideoDecoderConfig::IsValidConfig().
   static bool IsValidConfig(
       Format format,
       size_t width,
-      size_t height);
+      size_t height,
+      size_t alignment);
+  // TODO(scherkus): VideoDecoderConfig shouldn't call this method
+  static bool IsValidConfig(
+      Format format,
+      size_t width,
+      size_t height) {
+    return IsValidConfig(format, width, height, 1);
+  }
 
   // Wraps a native texture of the given parameters with a VideoFrame.  When the
   // frame is destroyed |no_longer_needed.Run()| will be called.
   static scoped_refptr<VideoFrame> WrapNativeTexture(
       uint32 texture_id,
       uint32 texture_target,
       size_t width,
       size_t height,
       base::TimeDelta timestamp,
       base::TimeDelta duration,
@@ skipping 58 matching lines @@
   friend class base::RefCountedThreadSafe<VideoFrame>;
   // Clients must use the static CreateFrame() method to create a new frame.
   VideoFrame(Format format,
              size_t video_width,
              size_t video_height,
              base::TimeDelta timestamp,
              base::TimeDelta duration);
   virtual ~VideoFrame();
 
   // Used internally by CreateFrame().
-  void AllocateRGB(size_t bytes_per_pixel);
-  void AllocateYUV();
+  void AllocateRGB(size_t bytes_per_pixel, size_t alignment);
+  void AllocateYUV(size_t alignment);
 
   // Used to DCHECK() plane parameters.
   bool IsValidPlane(size_t plane) const;
 
   // Frame format.
   Format format_;
 
   // Width and height of surface.
   size_t width_;
   size_t height_;
@@ skipping 13 matching lines @@
 
   base::TimeDelta timestamp_;
   base::TimeDelta duration_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_