Reverse rows in VP8 decoder.

remoting/base/decoder_vp8.cc

 // Copyright (c) 2010 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 "remoting/base/decoder_vp8.h"
 
 #include "media/base/media.h"
 #include "media/base/yuv_convert.h"
 #include "remoting/base/util.h"
 
 extern "C" {
 #define VPX_CODEC_DISABLE_COMPAT 1
 #include "third_party/libvpx/include/vpx/vpx_codec.h"
 #include "third_party/libvpx/include/vpx/vpx_decoder.h"
 #include "third_party/libvpx/include/vpx/vp8dx.h"
 }
 
 namespace remoting {
 
 DecoderVp8::DecoderVp8()
-    : state_(kUninitialized),
+    : reverse_rows_(true),
+      state_(kUninitialized),
       codec_(NULL) {
 }
 
 DecoderVp8::~DecoderVp8() {
   if (codec_) {
     vpx_codec_err_t ret = vpx_codec_destroy(codec_);
     CHECK(ret == VPX_CODEC_OK) << "Failed to destroy codec";
   }
   delete codec_;
 }
@@ skipping 43 matching lines @@
 
   // Gets the decoded data.
   vpx_codec_iter_t iter = NULL;
   vpx_image_t* image = vpx_codec_get_frame(codec_, &iter);
   if (!image) {
     LOG(INFO) << "No video frame decoded";
     return DECODE_ERROR;
   }
 
   // Perform YUV conversion.
+  uint8* data_start = frame_->data(media::VideoFrame::kRGBPlane);
+  int stride = frame_->stride(media::VideoFrame::kRGBPlane);
+  if (reverse_rows_) {
+    data_start = data_start + (frame_->height() - 1) * stride;
+    stride = -stride;
+  }
+
   media::ConvertYUVToRGB32(image->planes[0], image->planes[1], image->planes[2],
-                           frame_->data(media::VideoFrame::kRGBPlane),
-                           frame_->width(), frame_->height(),
-                           image->stride[0], image->stride[1],
-                           frame_->stride(media::VideoFrame::kRGBPlane),
+                           data_start, frame_->width(), frame_->height(),
+                           image->stride[0], image->stride[1], stride,
                            media::YV12);
   return DECODE_DONE;
 }
 
 void DecoderVp8::GetUpdatedRects(UpdatedRects* rects) {
 }
 
 void DecoderVp8::Reset() {
   frame_ = NULL;
   state_ = kUninitialized;
 }
 
 bool DecoderVp8::IsReadyForData() {
   return state_ == kReady;
 }
 
 VideoPacketFormat::Encoding DecoderVp8::Encoding() {
   return VideoPacketFormat::ENCODING_VP8;
 }
 
 }  // namespace remoting