[experimental] MR: add support for H264 recording

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 <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/sys_info.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 #include "ui/gfx/geometry/size.h"
 
 extern "C" {
 // VPX_CODEC_DISABLE_COMPAT excludes parts of the libvpx API that provide
 // backwards compatibility for legacy applications using the library.
 #define VPX_CODEC_DISABLE_COMPAT 1
 #include "third_party/libvpx/source/libvpx/vpx/vp8cx.h"
 #include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
 }
 
+#include "third_party/openh264/src/codec/api/svc/codec_api.h"
+#include "third_party/openh264/src/codec/api/svc/codec_app_def.h"
+#include "third_party/openh264/src/codec/api/svc/codec_def.h"
+
 using media::VideoFrame;
 using media::VideoFrameMetadata;
 
 namespace content {
 
 namespace {
 
 const vpx_codec_flags_t kNoFlags = 0;
 
 // Originally from remoting/codec/scoped_vpx_codec.h.
@@ skipping 16 matching lines @@
     std::unique_ptr<std::string> data,
     base::TimeTicks capture_timestamp,
     bool keyframe) {
   DVLOG(1) << (keyframe ? "" : "non ") << "keyframe "<< data->length() << "B, "
            << capture_timestamp << " ms";
   on_encoded_video_cb.Run(frame, std::move(data), capture_timestamp, keyframe);
 }
 
 }  // anonymous namespace
 
+class VideoTrackRecorder::Encoder : public base::RefCountedThreadSafe<Encoder> {
+ public:
+  virtual void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
+                                base::TimeTicks capture_timestamp) = 0;
+
+  virtual void set_paused(bool paused) = 0;
+
+ protected:
+  friend class base::RefCountedThreadSafe<Encoder>;
+  virtual ~Encoder() {}
+};
+
+namespace {
+
 // Inner class encapsulating all libvpx interactions and the encoding+delivery
 // of received frames. Limitation: Only VP8 is supported for the time being.
 // This class must be ref-counted because the MediaStreamVideoTrack will hold a
 // reference to it, via the callback MediaStreamVideoSink passes along, and it's
 // unknown when exactly it will release that reference. This class:
 // - is created and destroyed on its parent's thread (usually the main Render
 // thread);
 // - receives VideoFrames and Run()s the callbacks on |origin_task_runner_|,
 // which is cached on first frame arrival, and is supposed to be the render IO
 // thread, but this is not enforced;
 // - uses an internal |encoding_thread_| for libvpx interactions, notably for
 // encoding (which might take some time).
-class VideoTrackRecorder::VpxEncoder final
-    : public base::RefCountedThreadSafe<VpxEncoder> {
+class VpxEncoder final : public VideoTrackRecorder::Encoder {
  public:
   static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
                               ScopedVpxCodecCtxPtr encoder);
 
-  VpxEncoder(bool use_vp9,
-             const OnEncodedVideoCB& on_encoded_video_callback,
-             int32_t bits_per_second);
+  VpxEncoder(
+      bool use_vp9,
+      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
+      int32_t bits_per_second);
 
   void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
-                        base::TimeTicks capture_timestamp);
+                        base::TimeTicks capture_timestamp) override;
 
-  void set_paused(bool paused) { paused_ = paused; }
+  void set_paused(bool paused) override { paused_ = paused; }
 
  private:
-  friend class base::RefCountedThreadSafe<VpxEncoder>;
-  ~VpxEncoder();
+  ~VpxEncoder() override;
 
   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_;
 
   // This callback should be exercised on IO thread.
-  const OnEncodedVideoCB on_encoded_video_callback_;
+  const VideoTrackRecorder::OnEncodedVideoCB on_encoded_video_callback_;
 
   // Target bitrate or video encoding. If 0, a standard bitrate is used.
   const int32_t bits_per_second_;
 
   // 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_;
 
   // Thread for encoding. Active for the lifetime of VpxEncoder. All variables
   // below this are used in this thread.
   std::unique_ptr<base::Thread> encoding_thread_;
   // VP8 internal objects: configuration and encoder.
   vpx_codec_enc_cfg_t codec_config_;
   // |encoder_| is a special scoped pointer to guarantee proper destruction.
   // Again, it should only be accessed on |encoding_thread_|.
   ScopedVpxCodecCtxPtr encoder_;
 
+
   // The |VideoFrame::timestamp()| of the last encoded frame.  This is used to
   // predict the duration of the next frame.
   base::TimeDelta last_frame_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(VpxEncoder);
 };
 
+class H264Encoder final : public VideoTrackRecorder::Encoder {
+ public:
+  static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
+                              scoped_ptr<ISVCEncoder> encoder);
+
+  H264Encoder(
+      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
+      int32_t bits_per_second);
+
+  void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
+                        base::TimeTicks capture_timestamp) override;
+
+  void set_paused(bool paused) override { paused_ = paused; }
+
+ private:
+  ~H264Encoder() override;
+
+  void EncodeOnEncodingThread(const scoped_refptr<VideoFrame>& frame,
+                              base::TimeTicks capture_timestamp);
+
+  void ConfigureEncoding(const gfx::Size& size);
+
+  // While |paused_|, frames are not encoded.
+  bool paused_;
+
+  // This callback should be exercised on IO thread.
+  const VideoTrackRecorder::OnEncodedVideoCB on_encoded_video_callback_;
+
+  // Target bitrate or video encoding. If 0, a standard bitrate is used.
+  const int32_t bits_per_second_;
+
+  // 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_;
+
+  // Thread for encoding. Active for the lifetime of VpxEncoder. All variables
+  // below this are used in this thread.
+  std::unique_ptr<base::Thread> encoding_thread_;
+
+  scoped_ptr<ISVCEncoder> openh264_encoder_;
+  gfx::Size configured_size_;
+
+  // The |VideoFrame::timestamp()| of the first received frame.
+  base::TimeTicks first_frame_timestamp_;
+
+  DISALLOW_COPY_AND_ASSIGN(H264Encoder);
+};
+
 // static
-void VideoTrackRecorder::VpxEncoder::ShutdownEncoder(
-    std::unique_ptr<base::Thread> encoding_thread,
-    ScopedVpxCodecCtxPtr encoder) {
+void H264Encoder::ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
+                                  scoped_ptr<ISVCEncoder> encoder) {
+  DVLOG(1) << __FUNCTION__;
+  DCHECK(encoding_thread->IsRunning());
+  encoding_thread->Stop();
+
+  if (encoder) {
+    const int uninit_ret = encoder->Uninitialize();
+    DLOG_IF(ERROR, uninit_ret != 0)  << "OpenH264 Uninitialize()";
+
+    WelsDestroySVCEncoder(encoder.release());
+  }
+}
+
+H264Encoder::H264Encoder(
+    const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
+    int32_t bits_per_second)
+    : paused_(false),
+      on_encoded_video_callback_(on_encoded_video_callback),
+      bits_per_second_(bits_per_second),
+      main_task_runner_(base::MessageLoop::current()->task_runner()),
+      encoding_thread_(new base::Thread("EncodingThread")) {
+  DCHECK(!on_encoded_video_callback_.is_null());
+
+  DCHECK(!encoding_thread_->IsRunning());
+  encoding_thread_->Start();
+}
+
+void H264Encoder::StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
+                                   base::TimeTicks capture_timestamp) {
+  DVLOG(1) << __FUNCTION__;
+  // 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;
+  encoding_thread_->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&H264Encoder::EncodeOnEncodingThread,
+                            this, frame, capture_timestamp));
+}
+
+
+void H264Encoder::EncodeOnEncodingThread(
+    const scoped_refptr<VideoFrame>& video_frame,
+    base::TimeTicks capture_timestamp) {
+  DVLOG(1) << __FUNCTION__;
+  DCHECK(encoding_thread_->task_runner()->BelongsToCurrentThread());
+
+  if (!(video_frame->format() == media::PIXEL_FORMAT_I420 ||
+        video_frame->format() == media::PIXEL_FORMAT_YV12 ||
+        video_frame->format() == media::PIXEL_FORMAT_YV12A)) {
+    NOTREACHED();
+    return;
+  }
+  scoped_refptr<media::VideoFrame> frame = video_frame;
+  // Drop alpha channel since we do not support it yet.
+  if (frame->format() == media::PIXEL_FORMAT_YV12A)
+    frame = media::WrapAsI420VideoFrame(video_frame);
+
+  const gfx::Size frame_size = frame->visible_rect().size();
+  if (!openh264_encoder_ || configured_size_ != frame_size) {
+    ConfigureEncoding(frame_size);
+    first_frame_timestamp_ = capture_timestamp;
+  }
+
+  DCHECK(openh264_encoder_);
+
+  // EncodeFrame input.
+  SSourcePicture picture = {};
+  picture.iPicWidth = frame_size.width();
+  picture.iPicHeight = frame_size.height();
+  picture.iColorFormat = EVideoFormatType::videoFormatI420;
+  picture.uiTimeStamp =
+      (capture_timestamp - first_frame_timestamp_).InMilliseconds();
+  picture.iStride[0] = video_frame->stride(VideoFrame::kYPlane);
+  picture.iStride[1] = video_frame->stride(VideoFrame::kUPlane);
+  picture.iStride[2] = video_frame->stride(VideoFrame::kVPlane);
+  picture.pData[0] = video_frame->data(VideoFrame::kYPlane);
+  picture.pData[1] = video_frame->data(VideoFrame::kUPlane);
+  picture.pData[2] = video_frame->data(VideoFrame::kVPlane);
+
+  // EncodeFrame output.
+  SFrameBSInfo info;
+  memset(&info, 0, sizeof(SFrameBSInfo));
+
+  // Encode!
+  int enc_ret = openh264_encoder_->EncodeFrame(&picture, &info);
+  if (enc_ret != cmResultSuccess) {
+    DLOG(ERROR) << "OpenH264 encoding failed, EncodeFrame says " << enc_ret;
+    NOTREACHED();
+    return;
+  }
+
+  std::unique_ptr<std::string> data(new std::string);
+  const uint8_t kNALStartCode[4] = {0, 0, 0, 1};
+  for (int layer = 0; layer < info.iLayerNum; ++layer) {
+    const SLayerBSInfo& layerInfo = info.sLayerInfo[layer];
+    // Iterate NAL units making up this layer, noting fragments.
+    size_t layer_len = 0;
+    for (int nal = 0; nal < layerInfo.iNalCount; ++nal) {
+
+      DCHECK_GE(layerInfo.pNalLengthInByte[nal], 4);
+      DCHECK_EQ(kNALStartCode[0], layerInfo.pBsBuf[layer_len+0]);
+      DCHECK_EQ(kNALStartCode[1], layerInfo.pBsBuf[layer_len+1]);
+      DCHECK_EQ(kNALStartCode[2], layerInfo.pBsBuf[layer_len+2]);
+      DCHECK_EQ(kNALStartCode[3], layerInfo.pBsBuf[layer_len+3]);
+
+      layer_len += layerInfo.pNalLengthInByte[nal];
+    }
+    // Copy the entire layer's data (including start codes).
+    data->append(reinterpret_cast<char*>(layerInfo.pBsBuf), layer_len);
+  }
+
+  const bool is_key_frame = info.eFrameType == videoFrameTypeIDR;
+
+  origin_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(OnFrameEncodeCompleted, on_encoded_video_callback_, frame,
+                 base::Passed(&data), capture_timestamp, is_key_frame));
+}
+
+void H264Encoder::ConfigureEncoding(const gfx::Size& size) {
+  DVLOG(1) << __FUNCTION__;
+  configured_size_ = size;
+
+  ISVCEncoder* temp_encoder = nullptr;
+  int result = WelsCreateSVCEncoder(&temp_encoder);
+  if (result != 0) {
+    DLOG(ERROR) << "Failed to create OpenH264 encoder";
+    NOTREACHED();
+    return;
+  }
+  openh264_encoder_.reset(temp_encoder);
+
+#if DCHECK_IS_ON()
+  int trace_level = WELS_LOG_DETAIL;
+  openh264_encoder_->SetOption(ENCODER_OPTION_TRACE_LEVEL, &trace_level);
+#endif
+
+  SEncParamExt init_params;
+  openh264_encoder_->GetDefaultParams(&init_params);
+  init_params.iUsageType = CAMERA_VIDEO_REAL_TIME;
+
+  init_params.iPicWidth = size.width();
+  init_params.iPicHeight = size.height();
+  if (bits_per_second_ > 0) {
+    init_params.iRCMode = RC_BITRATE_MODE;
+    init_params.iTargetBitrate = bits_per_second_;
+  } else {
+    init_params.iRCMode = RC_OFF_MODE;
+  }
+
+  // Do not saturate CPU utilization just for encoding. On a lower-end system
+  // with only 1 or 2 cores, use only one thread for encoding. On systems with
+  // more cores, allow half of the cores to be used for encoding.
+  init_params.iMultipleThreadIdc =
+      std::min(8, (base::SysInfo::NumberOfProcessors() + 1) / 2);
+
+  // The base spatial layer 0 is the only one we use.
+  DCHECK_EQ(1, init_params.iSpatialLayerNum);
+  init_params.sSpatialLayers[0].iVideoWidth        = init_params.iPicWidth;
+  init_params.sSpatialLayers[0].iVideoHeight       = init_params.iPicHeight;
+  init_params.sSpatialLayers[0].iSpatialBitrate    = init_params.iTargetBitrate;
+
+  result = openh264_encoder_->InitializeExt(&init_params);
+  if (result != cmResultSuccess) {
+    DLOG(ERROR) << "Failed to initialize OpenH264 encoder";
+    NOTREACHED();
+    return;
+  }
+
+  int video_format = EVideoFormatType::videoFormatI420;
+  openh264_encoder_->SetOption(ENCODER_OPTION_DATAFORMAT,
+                               &video_format);
+}
+
+H264Encoder::~H264Encoder() {
+  main_task_runner_->PostTask(FROM_HERE,
+                              base::Bind(&H264Encoder::ShutdownEncoder,
+                                         base::Passed(&encoding_thread_),
+                                         base::Passed(&openh264_encoder_)));
+}
+
+//
+//
+// static
+void VpxEncoder::ShutdownEncoder(std::unique_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(
+VpxEncoder::VpxEncoder(
     bool use_vp9,
-    const OnEncodedVideoCB& on_encoded_video_callback,
+    const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
     int32_t bits_per_second)
     : paused_(false),
       use_vp9_(use_vp9),
       on_encoded_video_callback_(on_encoded_video_callback),
       bits_per_second_(bits_per_second),
       main_task_runner_(base::MessageLoop::current()->task_runner()),
       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() {
+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) {
+void 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;
   encoding_thread_->task_runner()->PostTask(
       FROM_HERE, base::Bind(&VpxEncoder::EncodeOnEncodingThread,
                             this, frame, capture_timestamp));
 }
 
-void VideoTrackRecorder::VpxEncoder::EncodeOnEncodingThread(
+void VpxEncoder::EncodeOnEncodingThread(
     const scoped_refptr<VideoFrame>& video_frame,
     base::TimeTicks capture_timestamp) {
   TRACE_EVENT0("video",
-               "VideoTrackRecorder::VpxEncoder::EncodeOnEncodingThread");
+               "VpxEncoder::EncodeOnEncodingThread");
   DCHECK(encoding_thread_->task_runner()->BelongsToCurrentThread());
 
   if (!(video_frame->format() == media::PIXEL_FORMAT_I420 ||
         video_frame->format() == media::PIXEL_FORMAT_YV12 ||
         video_frame->format() == media::PIXEL_FORMAT_YV12A)) {
     NOTREACHED();
     return;
   }
   scoped_refptr<media::VideoFrame> frame = video_frame;
   // Drop alpha channel since we do not support it yet.
@@ skipping 48 matching lines @@
   }
   origin_task_runner_->PostTask(FROM_HERE,
       base::Bind(OnFrameEncodeCompleted,
                  on_encoded_video_callback_,
                  frame,
                  base::Passed(&data),
                  capture_timestamp,
                  keyframe));
 }
 
-void VideoTrackRecorder::VpxEncoder::ConfigureEncoding(const gfx::Size& size) {
+void VpxEncoder::ConfigureEncoding(const gfx::Size& size) {
   if (IsInitialized()) {
     // TODO(mcasas) VP8 quirk/optimisation: If the new |size| is strictly less-
     // than-or-equal than the old size, in terms of area, the existing encoder
     // instance could be reused after changing |codec_config_.{g_w,g_h}|.
     DVLOG(1) << "Destroying/Re-Creating encoder for new frame size: "
              << gfx::Size(codec_config_.g_w, codec_config_.g_h).ToString()
              << " --> " << size.ToString() << (use_vp9_ ? " vp9" : " vp8");
     encoder_.reset();
   }
 
@@ skipping 71 matching lines @@
     // the expense of quality up to a maximum value of 8 for VP9, by tuning the
     // target time spent encoding the frame. Go from 8 to 5 (values for real
     // time encoding) depending on the amount of cores available in the system.
     const int kCpuUsed =
         std::max(5, 8 - base::SysInfo::NumberOfProcessors() / 2);
     result = vpx_codec_control(encoder_.get(), VP8E_SET_CPUUSED, kCpuUsed);
     DLOG_IF(WARNING, VPX_CODEC_OK != result) << "VP8E_SET_CPUUSED failed";
   }
 }
 
-bool VideoTrackRecorder::VpxEncoder::IsInitialized() const {
+bool VpxEncoder::IsInitialized() const {
   DCHECK(encoding_thread_->task_runner()->BelongsToCurrentThread());
   return codec_config_.g_timebase.den != 0;
 }
 
-base::TimeDelta VideoTrackRecorder::VpxEncoder::CalculateFrameDuration(
+base::TimeDelta VpxEncoder::CalculateFrameDuration(
     const scoped_refptr<VideoFrame>& frame) {
   DCHECK(encoding_thread_->task_runner()->BelongsToCurrentThread());
 
   using base::TimeDelta;
   TimeDelta predicted_frame_duration;
   if (!frame->metadata()->GetTimeDelta(VideoFrameMetadata::FRAME_DURATION,
                                        &predicted_frame_duration) ||
       predicted_frame_duration <= TimeDelta()) {
     // The source of the video frame did not provide the frame duration.  Use
     // the actual amount of time between the current and previous frame as a
     // prediction for the next frame's duration.
     // TODO(mcasas): This duration estimation could lead to artifacts if the
     // cadence of the received stream is compromised (e.g. camera freeze, pause,
     // remote packet loss).  Investigate using GetFrameRate() in this case.
     predicted_frame_duration = frame->timestamp() - last_frame_timestamp_;
   }
   last_frame_timestamp_ = frame->timestamp();
   // Make sure |predicted_frame_duration| is in a safe range of values.
   const TimeDelta kMaxFrameDuration = TimeDelta::FromSecondsD(1.0 / 8);
   const TimeDelta kMinFrameDuration = TimeDelta::FromMilliseconds(1);
   return std::min(kMaxFrameDuration, std::max(predicted_frame_duration,
                                               kMinFrameDuration));
 }
 
+}  // anonymous namespace
+
 VideoTrackRecorder::VideoTrackRecorder(
-    bool use_vp9,
+    CodecId codec,
     const blink::WebMediaStreamTrack& track,
     const OnEncodedVideoCB& on_encoded_video_callback,
     int32_t bits_per_second)
-    : track_(track),
-      encoder_(
-          new VpxEncoder(use_vp9, on_encoded_video_callback, bits_per_second)) {
+    : track_(track) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!track_.isNull());
   DCHECK(track_.getExtraData());
 
+  switch (codec) {
+    case CodecId::H264:
+      encoder_ = new H264Encoder(on_encoded_video_callback, bits_per_second);
+      break;
+    case CodecId::VP8:
+    case CodecId::VP9:
+      encoder_ = new VpxEncoder(codec == CodecId::VP9,
+                                on_encoded_video_callback, bits_per_second);
+      break;
+    default:
+      NOTREACHED();
+  }
+
   // StartFrameEncode() will be called on Render IO thread.
   MediaStreamVideoSink::ConnectToTrack(
       track_,
-      base::Bind(&VideoTrackRecorder::VpxEncoder::StartFrameEncode, encoder_));
+      base::Bind(&VideoTrackRecorder::Encoder::StartFrameEncode, encoder_));
 }
 
 VideoTrackRecorder::~VideoTrackRecorder() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   MediaStreamVideoSink::DisconnectFromTrack();
   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