Chrome MediaStream VideoTrack implementation.

content/renderer/media/rtc_video_renderer.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 "content/renderer/media/rtc_video_renderer.h"
 
 #include "base/debug/trace_event.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 
 namespace content {
 
+// Empty method used for keeping a reference to the original media::VideoFrame
+// in RTCVideoRenderer::OnVideoFrame if a color conversion between I420 and
+// YV12 is needed.
+static void ReleaseOriginalFrame(
+    const scoped_refptr<media::VideoFrame>& frame) {
+}
+
 RTCVideoRenderer::RTCVideoRenderer(
     const blink::WebMediaStreamTrack& video_track,
     const base::Closure& error_cb,
     const RepaintCB& repaint_cb)
     : error_cb_(error_cb),
       repaint_cb_(repaint_cb),
       message_loop_proxy_(base::MessageLoopProxy::current()),
       state_(STOPPED),
       first_frame_rendered_(false),
       video_track_(video_track) {
@@ skipping 57 matching lines @@
   DCHECK(message_loop_proxy_->BelongsToCurrentThread());
   if (state_ != STARTED) {
     return;
   }
 
   TRACE_EVENT_INSTANT1("rtc_video_renderer",
                        "OnVideoFrame",
                        TRACE_EVENT_SCOPE_THREAD,
                        "timestamp",
                        frame->GetTimestamp().InMilliseconds());
-  repaint_cb_.Run(frame);
   first_frame_rendered_ = true;
+
+  if (frame->format() != media::VideoFrame::I420) {
+    repaint_cb_.Run(frame);

[Ronghua Wu (Left Chromium), 2014/03/04 01:04:11]

what formats are expected here?

It seems YV12 will come here too.

[perkj_chrome, 2014/03/04 10:44:51]

That is correct. We need to special handle I420. See the added comment.

+    return;
+  }
+
+  scoped_refptr<media::VideoFrame> yuv_frame =

[Alpha Left Google, 2014/03/03 06:45:04]

A comment would help to explain what this is doing and why it is necessary.

[perkj_chrome, 2014/03/04 10:44:51]

Done.

+      media::VideoFrame::WrapExternalYuvData(
+          media::VideoFrame::YV12,
+          frame->coded_size(),
+          frame->visible_rect(),
+          frame->natural_size(),
+          frame->stride(media::VideoFrame::kYPlane),
+          frame->stride(media::VideoFrame::kUPlane),
+          frame->stride(media::VideoFrame::kVPlane),
+          frame->data(media::VideoFrame::kYPlane),
+          frame->data(media::VideoFrame::kUPlane),
+          frame->data(media::VideoFrame::kVPlane),
+          frame->GetTimestamp(),
+          base::Bind(&ReleaseOriginalFrame, frame));
+  repaint_cb_.Run(yuv_frame);
 }
 
 void RTCVideoRenderer::MaybeRenderSignalingFrame() {
   // Render a small black frame if no frame has been rendered.
   // This is necessary to make sure audio can play if the video tag src is
   // a MediaStream video track that has been rejected, ended or disabled.
   if (first_frame_rendered_)
     return;
 
   const int kMinFrameSize = 2;
   const gfx::Size size(kMinFrameSize, kMinFrameSize);
   scoped_refptr<media::VideoFrame> video_frame =
       media::VideoFrame::CreateBlackFrame(size);
   OnVideoFrame(video_frame);
 }
 
 }  // namespace content