MediaStream Recorder: implement pause() and resume()

content/renderer/media/video_track_recorder.cc

 // Copyright 2015 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/video_track_recorder.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/sys_info.h"
 #include "base/threading/thread.h"
@@ skipping 62 matching lines @@
     : public base::RefCountedThreadSafe<VpxEncoder> {
  public:
   static void ShutdownEncoder(scoped_ptr<base::Thread> encoding_thread,
                               ScopedVpxCodecCtxPtr encoder);
 
   VpxEncoder(bool use_vp9, const OnEncodedVideoCB& on_encoded_video_callback);
 
   void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
                         base::TimeTicks capture_timestamp);
 
+  void set_paused(bool paused) { paused_ = paused; }
+
  private:
   friend class base::RefCountedThreadSafe<VpxEncoder>;
   ~VpxEncoder();
 
   void EncodeOnEncodingThread(const scoped_refptr<VideoFrame>& frame,
                               base::TimeTicks capture_timestamp);
 
   void ConfigureEncoding(const gfx::Size& size);
 
   // Returns true if |codec_config_| has been filled in at least once.
   bool IsInitialized() const;
 
   // Estimate the frame duration from |frame| and |last_frame_timestamp_|.
   base::TimeDelta CalculateFrameDuration(
       const scoped_refptr<VideoFrame>& frame);
 
+  // While |paused_|, frames are not encoded.
+  bool paused_;
+
   // Force usage of VP9 for encoding, instead of VP8 which is the default.
   const bool use_vp9_;
 
   // Used to shutdown properly on the same thread we were created.
   const scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
   // Task runner where frames to encode and reply callbacks must happen.
   scoped_refptr<base::SingleThreadTaskRunner> origin_task_runner_;
 
   // This callback should be exercised on IO thread.
@@ skipping 20 matching lines @@
     scoped_ptr<base::Thread> encoding_thread,
     ScopedVpxCodecCtxPtr encoder) {
   DCHECK(encoding_thread->IsRunning());
   encoding_thread->Stop();
   // Both |encoding_thread| and |encoder| will be destroyed at end-of-scope.
 }
 
 VideoTrackRecorder::VpxEncoder::VpxEncoder(
     bool use_vp9,
     const OnEncodedVideoCB& on_encoded_video_callback)
-    : use_vp9_(use_vp9),
+    : paused_(false),
+      use_vp9_(use_vp9),
       main_task_runner_(base::MessageLoop::current()->task_runner()),
       on_encoded_video_callback_(on_encoded_video_callback),
       encoding_thread_(new base::Thread("EncodingThread")) {
   DCHECK(!on_encoded_video_callback_.is_null());
 
   codec_config_.g_timebase.den = 0;  // Not initialized.
 
   DCHECK(!encoding_thread_->IsRunning());
   encoding_thread_->Start();
 }
 
 VideoTrackRecorder::VpxEncoder::~VpxEncoder() {
   main_task_runner_->PostTask(FROM_HERE,
                               base::Bind(&VpxEncoder::ShutdownEncoder,
                                          base::Passed(&encoding_thread_),
                                          base::Passed(&encoder_)));
 }
 
 void VideoTrackRecorder::VpxEncoder::StartFrameEncode(
     const scoped_refptr<VideoFrame>& frame,
     base::TimeTicks capture_timestamp) {
   // Cache the thread sending frames on first frame arrival.
   if (!origin_task_runner_.get())
     origin_task_runner_ = base::MessageLoop::current()->task_runner();
   DCHECK(origin_task_runner_->BelongsToCurrentThread());
-
+  if (paused_)
+    return;

[emircan, 2015/10/20 22:00:27]

Move to l.167?

   encoding_thread_->task_runner()->PostTask(
       FROM_HERE, base::Bind(&VpxEncoder::EncodeOnEncodingThread,
                             this, frame, capture_timestamp));
 }
 
 void VideoTrackRecorder::VpxEncoder::EncodeOnEncodingThread(
     const scoped_refptr<VideoFrame>& frame,
     base::TimeTicks capture_timestamp) {
   TRACE_EVENT0("video",
                "VideoTrackRecorder::VpxEncoder::EncodeOnEncodingThread");
@@ skipping 175 matching lines @@
                              encoder_),
                   track_);
 }
 
 VideoTrackRecorder::~VideoTrackRecorder() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   RemoveFromVideoTrack(this, track_);
   track_.reset();
 }
 
+void VideoTrackRecorder::Pause() {
+  DCHECK(main_render_thread_checker_.CalledOnValidThread());
+  DCHECK(encoder_);
+  encoder_->set_paused(true);
+}
+
+void VideoTrackRecorder::Resume() {
+  DCHECK(main_render_thread_checker_.CalledOnValidThread());
+  DCHECK(encoder_);
+  encoder_->set_paused(false);
+}
+
 void VideoTrackRecorder::OnVideoFrameForTesting(
     const scoped_refptr<media::VideoFrame>& frame,
     base::TimeTicks timestamp) {
   encoder_->StartFrameEncode(frame, timestamp);
 }
 
 }  // namespace content