Preliminary change for new rtc rendering algorithm

content/renderer/media/webrtc/media_stream_remote_video_source.cc

 // Copyright 2014 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/webrtc/media_stream_remote_video_source.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/threading/thread_checker.h"
@@ skipping 44 matching lines @@
         const VideoCaptureDeliverFrameCB& new_frame_callback)
     : io_task_runner_(io_task_runner), frame_callback_(new_frame_callback) {
 }
 
 MediaStreamRemoteVideoSource::
 RemoteVideoSourceDelegate::~RemoteVideoSourceDelegate() {
 }
 
 void MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::RenderFrame(
     const cricket::VideoFrame* incoming_frame) {
-  TRACE_EVENT0("webrtc", "RemoteVideoSourceDelegate::RenderFrame");
+  TRACE_EVENT_BEGIN0("webrtc", "RemoteVideoSourceDelegate::RenderFrame");

[DaleCurtis, 2015/07/31 17:48:27]

Ditto.

[qiangchen, 2015/07/31 20:06:07]

Done.

   base::TimeDelta timestamp = base::TimeDelta::FromMicroseconds(
       incoming_frame->GetElapsedTime() / rtc::kNumNanosecsPerMicrosec);
 
   scoped_refptr<media::VideoFrame> video_frame;
   if (incoming_frame->GetNativeHandle() != NULL) {
     video_frame =
         static_cast<media::VideoFrame*>(incoming_frame->GetNativeHandle());
     video_frame->set_timestamp(timestamp);
   } else {
     const cricket::VideoFrame* frame =
@@ skipping 13 matching lines @@
     video_frame = media::VideoFrame::WrapExternalYuvData(
         media::PIXEL_FORMAT_YV12, size, gfx::Rect(size), size,
         frame->GetYPitch(), frame->GetUPitch(), frame->GetVPitch(),
         const_cast<uint8_t*>(frame->GetYPlane()),
         const_cast<uint8_t*>(frame->GetUPlane()),
         const_cast<uint8_t*>(frame->GetVPlane()), timestamp);
     video_frame->AddDestructionObserver(
         base::Bind(&base::DeletePointer<cricket::VideoFrame>, frame->Copy()));
   }
 
+  base::TimeTicks render_time =
+      base::TimeTicks::FromInternalValue(incoming_frame->GetTimeStamp() / 1000);

[DaleCurtis, 2015/07/31 17:48:27]

This still isn't correct unless the value returned by GetTimeStamp is based on
the same clock as base::TimeTicks::Now().  Even then you should instead use
base::TimeTicks() + base::TimeDelta::FromMicroseconds() then.

[qiangchen, 2015/07/31 20:06:07]

This is a good point. The timestamp is from WebRTC, essentially
webrtc::TickTime::Now(), is that the same with base::TimeTicks::Now()? In my
testing, they are the same, but I'm not sure whether this may be platform
specific. Or is it better to do a re-alignment here?

[DaleCurtis, 2015/08/03 21:08:04]

If they're the same then using FromMicroseconds() + base::TimeTicks() is okay,
but you should be sure they are the same -- otherwise yes you should do a
realignment before exposing it outside of WebRTC like this.

+  video_frame->metadata()->SetTimeTicks(
+      media::VideoFrameMetadata::REFERENCE_TIME,
+      render_time);
+
+  TRACE_EVENT_END1("webrtc", "RemoteVideoSourceDelegate::RenderFrame",
+                   "Ideal Render Instant", render_time.ToInternalValue());
+
   io_task_runner_->PostTask(
       FROM_HERE, base::Bind(&RemoteVideoSourceDelegate::DoRenderFrameOnIOThread,
                             this, video_frame));
 }
 
 void MediaStreamRemoteVideoSource::
 RemoteVideoSourceDelegate::DoRenderFrameOnIOThread(
     const scoped_refptr<media::VideoFrame>& video_frame) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   TRACE_EVENT0("webrtc", "RemoteVideoSourceDelegate::DoRenderFrameOnIOThread");
@@ skipping 66 matching lines @@
     case webrtc::MediaStreamTrackInterface::kEnded:
       SetReadyState(blink::WebMediaStreamSource::ReadyStateEnded);
       break;
     default:
       NOTREACHED();
       break;
   }
 }
 
 }  // namespace content