H264: Improve FFmpeg decoder performance by using I420BufferPool.

webrtc/common_video/video_frame_buffer.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/common_video/include/video_frame_buffer.h"
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/keep_ref_until_done.h"
 
 // Aligning pointer to 64 bytes for improved performance, e.g. use SIMD.
 static const int kBufferAlignment = 64;
 
 namespace webrtc {
 
+namespace {
+
+int I420DataSize(int height, int stride_y, int stride_u, int stride_v) {
+  return stride_y * height + (stride_u + stride_v) * ((height + 1) / 2);
+}
+
+}  // namespace
+
 uint8_t* VideoFrameBuffer::MutableData(PlaneType type) {
   RTC_NOTREACHED();
   return nullptr;
 }
 
 VideoFrameBuffer::~VideoFrameBuffer() {}
 
 I420Buffer::I420Buffer(int width, int height)
     : I420Buffer(width, height, width, (width + 1) / 2, (width + 1) / 2) {
 }
 
 I420Buffer::I420Buffer(int width,
                        int height,
                        int stride_y,
                        int stride_u,
                        int stride_v)
     : width_(width),
       height_(height),
       stride_y_(stride_y),
       stride_u_(stride_u),
       stride_v_(stride_v),
       data_(static_cast<uint8_t*>(AlignedMalloc(
-          stride_y * height + (stride_u + stride_v) * ((height + 1) / 2),
+          I420DataSize(height, stride_y, stride_u, stride_v),
           kBufferAlignment))) {
   RTC_DCHECK_GT(width, 0);
   RTC_DCHECK_GT(height, 0);
   RTC_DCHECK_GE(stride_y, width);
   RTC_DCHECK_GE(stride_u, (width + 1) / 2);
   RTC_DCHECK_GE(stride_v, (width + 1) / 2);
 }
 
 I420Buffer::~I420Buffer() {
 }
 
+void I420Buffer::InitializeData() {
+  memset(data_.get(), 0,
+         I420DataSize(height_, stride_y_, stride_u_, stride_v_));
+}
+
 int I420Buffer::width() const {
   return width_;
 }
 
 int I420Buffer::height() const {
   return height_;
 }
 
 const uint8_t* I420Buffer::data(PlaneType type) const {
   switch (type) {
@@ skipping 164 matching lines @@
                            buffer->stride(kVPlane) * uv_offset_y + uv_offset_x;
   return new rtc::RefCountedObject<WrappedI420Buffer>(
       cropped_width, cropped_height,
       y_plane, buffer->stride(kYPlane),
       u_plane, buffer->stride(kUPlane),
       v_plane, buffer->stride(kVPlane),
       rtc::KeepRefUntilDone(buffer));
 }
 
 }  // namespace webrtc