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(
       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(

[scherkus (not reviewing), 2012/06/14 02:21:33]

I actually don't see any public users of this function!

what happens if you get rid of the one w/o alignment?

[rbultje1, 2012/06/14 18:32:20]

See video_decoder_config.cc

       Format format,
       size_t width,
-      size_t height);
+      size_t height,
+      size_t alignment);
+  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_