content/renderer/media/rtc_video_renderer.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/renderer/media/rtc_video_renderer.h"
   6
   7 #include "base/thread_task_runner_handle.h"
   8 #include "base/trace_event/trace_event.h"
   9 #include "media/base/bind_to_current_loop.h"
  10 #include "media/base/video_frame.h"
  11 #include "media/base/video_util.h"
  12
  13 const int kMinFrameSize = 2;
  14
  15 namespace content {
  16
  17 RTCVideoRenderer::RTCVideoRenderer(
  18     const blink::WebMediaStreamTrack& video_track,
  19     const base::Closure& error_cb,
  20     const RepaintCB& repaint_cb)
  21     : error_cb_(error_cb),
  22       repaint_cb_(repaint_cb),
  23       task_runner_(base::ThreadTaskRunnerHandle::Get()),
  24       state_(STOPPED),
  25       frame_size_(kMinFrameSize, kMinFrameSize),
  26       video_track_(video_track),
  27       weak_factory_(this) {
  28 }
  29
  30 RTCVideoRenderer::~RTCVideoRenderer() {
  31 }
  32
  33 void RTCVideoRenderer::Start() {
  34   DCHECK(task_runner_->BelongsToCurrentThread());
  35   DCHECK_EQ(state_, STOPPED);
  36
  37   AddToVideoTrack(
  38       this,
  39       media::BindToCurrentLoop(
  40           base::Bind(
  41               &RTCVideoRenderer::OnVideoFrame,
  42               weak_factory_.GetWeakPtr())),
  43       video_track_);
  44   state_ = STARTED;
  45
  46   if (video_track_.source().readyState() ==
  47           blink::WebMediaStreamSource::ReadyStateEnded ||
  48       !video_track_.isEnabled()) {
  49     RenderSignalingFrame();
  50   }
  51 }
  52
  53 void RTCVideoRenderer::Stop() {
  54   DCHECK(task_runner_->BelongsToCurrentThread());
  55   DCHECK(state_ == STARTED || state_ == PAUSED);
  56   RemoveFromVideoTrack(this, video_track_);
  57   weak_factory_.InvalidateWeakPtrs();
  58   state_ = STOPPED;
  59   frame_size_.set_width(kMinFrameSize);
  60   frame_size_.set_height(kMinFrameSize);
  61 }
  62
  63 void RTCVideoRenderer::Play() {
  64   DCHECK(task_runner_->BelongsToCurrentThread());
  65   if (state_ == PAUSED)
  66     state_ = STARTED;
  67 }
  68
  69 void RTCVideoRenderer::Pause() {
  70   DCHECK(task_runner_->BelongsToCurrentThread());
  71   if (state_ == STARTED)
  72     state_ = PAUSED;
  73 }
  74
  75 void RTCVideoRenderer::OnReadyStateChanged(
  76     blink::WebMediaStreamSource::ReadyState state) {
  77   DCHECK(task_runner_->BelongsToCurrentThread());
  78   if (state == blink::WebMediaStreamSource::ReadyStateEnded)
  79     RenderSignalingFrame();
  80 }
  81
  82 void RTCVideoRenderer::OnVideoFrame(
  83     const scoped_refptr<media::VideoFrame>& frame,
  84     const base::TimeTicks& estimated_capture_time) {
  85   DCHECK(task_runner_->BelongsToCurrentThread());
  86   if (state_ != STARTED)
  87     return;
  88
  89   frame_size_ = frame->natural_size();
  90
  91   TRACE_EVENT_INSTANT1("rtc_video_renderer",
  92                        "OnVideoFrame",
  93                        TRACE_EVENT_SCOPE_THREAD,
  94                        "timestamp",
  95                        frame->timestamp().InMilliseconds());
  96   repaint_cb_.Run(frame);
  97 }
  98
  99 void RTCVideoRenderer::RenderSignalingFrame() {
 100   // This is necessary to make sure audio can play if the video tag src is
 101   // a MediaStream video track that has been rejected or ended.
 102   // It also ensure that the renderer don't hold a reference to a real video
 103   // frame if no more frames are provided. This is since there might be a
 104   // finite number of available buffers. E.g, video that
 105   // originates from a video camera.
 106   scoped_refptr<media::VideoFrame> video_frame =
 107       media::VideoFrame::CreateBlackFrame(frame_size_);
 108   OnVideoFrame(video_frame, base::TimeTicks());
 109 }
 110
 111 }  // namespace content