media: Add support for playback of VP8 Alpha video streams

media/base/video_util.cc

 // 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.
 
 #include "media/base/video_util.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "media/base/video_frame.h"
@@ skipping 44 matching lines @@
 }
 
 void CopyUPlane(const uint8* source, int stride, int rows, VideoFrame* frame) {
   CopyPlane(VideoFrame::kUPlane, source, stride, rows, frame);
 }
 
 void CopyVPlane(const uint8* source, int stride, int rows, VideoFrame* frame) {
   CopyPlane(VideoFrame::kVPlane, source, stride, rows, frame);
 }
 
+void CopyAPlane(const uint8* source, int stride, int rows, VideoFrame* frame) {
+  CopyPlane(VideoFrame::kAPlane, source, stride, rows, frame);
+}
+
+void MakeOpaqueAPlane(int stride, int rows, VideoFrame* frame) {
+  int rows_to_clear = std::min(frame->rows(VideoFrame::kAPlane), rows);
+  memset(frame->data(VideoFrame::kAPlane), 255,
+         frame->stride(VideoFrame::kAPlane) * rows_to_clear);
+}
+
 void FillYUV(VideoFrame* frame, uint8 y, uint8 u, uint8 v) {
   // Fill the Y plane.
   uint8* y_plane = frame->data(VideoFrame::kYPlane);
   int y_rows = frame->rows(VideoFrame::kYPlane);
   int y_row_bytes = frame->row_bytes(VideoFrame::kYPlane);
   for (int i = 0; i < y_rows; ++i) {
     memset(y_plane, y, y_row_bytes);
     y_plane += frame->stride(VideoFrame::kYPlane);
   }
 
@@ skipping 208 matching lines @@
                     frame->data(kU) + uv_offset,
                     frame->data(kV) + uv_offset,
                     region_in_frame.width(),
                     region_in_frame.height(),
                     stride,
                     frame->stride(kY),
                     uv_stride);
 }
 
 }  // namespace media