Fixing peerconnection reddish video issue

webrtc/examples/peerconnection/client/linux/main_wnd.cc

 /*
  *  Copyright 2012 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.
  */
 
@@ skipping 510 matching lines @@
 void GtkMainWnd::VideoRenderer::OnFrame(
     const webrtc::VideoFrame& video_frame) {
   gdk_threads_enter();
 
   rtc::scoped_refptr<webrtc::VideoFrameBuffer> buffer(
       webrtc::I420Buffer::Rotate(video_frame.video_frame_buffer(),
                                  video_frame.rotation()));
 
   SetSize(buffer->width(), buffer->height());
 
-  libyuv::I420ToRGBA(buffer->DataY(), buffer->StrideY(),
+  libyuv::I420ToABGR(buffer->DataY(), buffer->StrideY(),

[tommi, 2017/01/02 15:37:49]

hmm... that's strange.  I don't think this has changed in a long while and the
regression sounds like something new.  Doesn't the image buffer end up being
used by gdk_draw_rgb_32_image?  Maybe there's something wrong with the scaling
code?

[kjellander_webrtc, 2017/01/03 09:24:26]

You're right we should probably look into what caused this. According to
https://chromium.googlesource.com/external/webrtc/+blame/master/webrtc/exampl...
it was changed as recently as Sep 1 by nisse in
https://chromium.googlesource.com/external/webrtc/+/9f8e37b6f833cb6c821c6f401...
Mirko: can you revert that CL locally and see if it solves the problem?

[mbonadei, 2017/01/03 12:10:23]

Yes, I checked out the commit before and the video was not reddish.
The first commit which exposes this behaviour is
9f8e37b6f833cb6c821c6f401421b7c33cbe4b27.

                      buffer->DataU(), buffer->StrideU(),
                      buffer->DataV(), buffer->StrideV(),
                      image_.get(), width_ * 4,
                      buffer->width(), buffer->height());
 
   gdk_threads_leave();
 
   g_idle_add(Redraw, main_wnd_);
 }