Refactor VideoTrackRecorder into smaller classes

content/renderer/media_recorder/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_recorder/video_track_recorder.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
-#include "base/sys_info.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
-#include "base/trace_event/trace_event.h"
 #include "cc/paint/skia_paint_canvas.h"
 #include "content/renderer/media/renderer_gpu_video_accelerator_factories.h"
+#include "content/renderer/media_recorder/vea_encoder.h"
+#include "content/renderer/media_recorder/vpx_encoder.h"
 #include "content/renderer/render_thread_impl.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 #include "media/filters/context_3d.h"
 #include "media/renderers/skcanvas_video_renderer.h"
 #include "services/ui/public/cpp/gpu/context_provider_command_buffer.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/libyuv/include/libyuv.h"
 #include "ui/gfx/geometry/size.h"
 
 #if BUILDFLAG(RTC_USE_H264)
-#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"
+#include "content/renderer/media_recorder/h264_encoder.h"
 #endif  // #if BUILDFLAG(RTC_USE_H264)
 
-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"
-}
-
 using media::VideoFrame;
-using media::VideoFrameMetadata;
 using video_track_recorder::kVEAEncoderMinResolutionWidth;
 using video_track_recorder::kVEAEncoderMinResolutionHeight;
 
 namespace content {
 
 namespace {
 
-// HW encoders expect a nonzero bitrate, so |kVEADefaultBitratePerPixel| is used
-// to estimate bits per second for ~30 fps with ~1/16 compression rate.
-const int kVEADefaultBitratePerPixel = 2;
-// Number of output buffers used to copy the encoded data coming from HW
-// encoders.
-const int kVEAEncoderOutputBufferCount = 4;
-
 using CodecId = VideoTrackRecorder::CodecId;
 
 static const struct {
   CodecId codec_id;
   media::VideoCodecProfile min_profile;
   media::VideoCodecProfile max_profile;
 } kPreferredCodecIdAndVEAProfiles[] = {
     {CodecId::VP8, media::VP8PROFILE_MIN, media::VP8PROFILE_MAX},
     {CodecId::VP9, media::VP9PROFILE_MIN, media::VP9PROFILE_MAX},
 #if BUILDFLAG(RTC_USE_H264)
@@ skipping 81 matching lines @@
 
 media::VideoCodecProfile CodecEnumerator::CodecIdToVEAProfile(CodecId codec) {
   const auto profile = codec_id_to_profile_.find(codec);
   return profile == codec_id_to_profile_.end()
              ? media::VIDEO_CODEC_PROFILE_UNKNOWN
              : profile->second;
 }
 
 }  // anonymous namespace
 
-// Base class to describe a generic Encoder, encapsulating all actual encoder
-// (re)configurations, encoding and delivery of received frames. This class is
-// ref-counted to allow the MediaStreamVideoTrack to hold a reference to it (via
-// the callback that MediaStreamVideoSink passes along) and to jump back and
-// forth to an internal encoder thread. Moreover, this class:
-// - is created on its parent's thread (usually the main Render thread),
-// that is, |main_task_runner_|.
-// - receives VideoFrames on |origin_task_runner_| and runs OnEncodedVideoCB on
-// that thread as well. This task runner is cached on first frame arrival, and
-// is supposed to be the render IO thread (but this is not enforced);
-// - uses an internal |encoding_task_runner_| for actual encoder interactions,
-// namely configuration, encoding (which might take some time) and destruction.
-// This task runner can be passed on the creation. If nothing is passed, a new
-// encoding thread is created and used.
-class VideoTrackRecorder::Encoder : public base::RefCountedThreadSafe<Encoder> {
- public:
-  Encoder(const OnEncodedVideoCB& on_encoded_video_callback,
-          int32_t bits_per_second,
-          scoped_refptr<base::SingleThreadTaskRunner> encoding_task_runner =
-              nullptr)
-      : main_task_runner_(base::ThreadTaskRunnerHandle::Get()),
-        encoding_task_runner_(encoding_task_runner),
-        paused_(false),
-        on_encoded_video_callback_(on_encoded_video_callback),
-        bits_per_second_(bits_per_second) {
-    DCHECK(!on_encoded_video_callback_.is_null());
-    if (encoding_task_runner_)
-      return;
-    encoding_thread_.reset(new base::Thread("EncodingThread"));
-    encoding_thread_->Start();
-    encoding_task_runner_ = encoding_thread_->task_runner();
-  }
+VideoTrackRecorder::Encoder::Encoder(
+    const OnEncodedVideoCB& on_encoded_video_callback,
+    int32_t bits_per_second,
+    scoped_refptr<base::SingleThreadTaskRunner> encoding_task_runner)
+    : main_task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      encoding_task_runner_(encoding_task_runner),
+      paused_(false),
+      on_encoded_video_callback_(on_encoded_video_callback),
+      bits_per_second_(bits_per_second) {
+  DCHECK(!on_encoded_video_callback_.is_null());
+  if (encoding_task_runner_)
+    return;
+  encoding_thread_.reset(new base::Thread("EncodingThread"));
+  encoding_thread_->Start();
+  encoding_task_runner_ = encoding_thread_->task_runner();
+}
 
-  // Start encoding |frame|, returning via |on_encoded_video_callback_|. This
-  // call will also trigger an encode configuration upon first frame arrival
-  // or parameter change, and an EncodeOnEncodingTaskRunner() to actually
-  // encode the frame. If the |frame|'s data is not directly available (e.g.
-  // it's a texture) then RetrieveFrameOnMainThread() is called, and if even
-  // that fails, black frames are sent instead.
-  void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
-                        base::TimeTicks capture_timestamp);
-  void RetrieveFrameOnMainThread(const scoped_refptr<VideoFrame>& video_frame,
-                                 base::TimeTicks capture_timestamp);
-
-  void SetPaused(bool paused);
-  virtual bool CanEncodeAlphaChannel() { return false; }
-
- protected:
-  friend class base::RefCountedThreadSafe<Encoder>;
-  virtual ~Encoder() {
-    main_task_runner_->DeleteSoon(FROM_HERE, video_renderer_.release());
-  }
-
-  virtual void EncodeOnEncodingTaskRunner(
-      scoped_refptr<VideoFrame> frame,
-      base::TimeTicks capture_timestamp) = 0;
-
-  // 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_;
-
-  // Task runner where encoding interactions happen.
-  scoped_refptr<base::SingleThreadTaskRunner> encoding_task_runner_;
-
-  // Optional thread for encoding. Active for the lifetime of VpxEncoder.
-  std::unique_ptr<base::Thread> encoding_thread_;
-
-  // While |paused_|, frames are not encoded. Used only from |encoding_thread_|.
-  bool paused_;
-
-  // This callback should be exercised on IO thread.
-  const OnEncodedVideoCB on_encoded_video_callback_;
-
-  // Target bitrate for video encoding. If 0, a standard bitrate is used.
-  const int32_t bits_per_second_;
-
-  // Used to retrieve incoming opaque VideoFrames (i.e. VideoFrames backed by
-  // textures). Created on-demand on |main_task_runner_|.
-  std::unique_ptr<media::SkCanvasVideoRenderer> video_renderer_;
-  SkBitmap bitmap_;
-  std::unique_ptr<cc::PaintCanvas> canvas_;
-
-  DISALLOW_COPY_AND_ASSIGN(Encoder);
-};
+VideoTrackRecorder::Encoder::~Encoder() {
+  main_task_runner_->DeleteSoon(FROM_HERE, video_renderer_.release());
+}
 
 void VideoTrackRecorder::Encoder::StartFrameEncode(
     const scoped_refptr<VideoFrame>& video_frame,
     base::TimeTicks capture_timestamp) {
   // Cache the thread sending frames on first frame arrival.
   if (!origin_task_runner_.get())
     origin_task_runner_ = base::ThreadTaskRunnerHandle::Get();
   DCHECK(origin_task_runner_->BelongsToCurrentThread());
   if (paused_)
     return;
@@ skipping 95 matching lines @@
       DLOG(ERROR) << "Error converting frame to I420";
       return;
     }
   }
 
   encoding_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Encoder::EncodeOnEncodingTaskRunner, this, frame,
                             capture_timestamp));
 }
 
-void VideoTrackRecorder::Encoder::SetPaused(bool paused) {
-  if (!encoding_task_runner_->BelongsToCurrentThread()) {
-    encoding_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&Encoder::SetPaused, this, paused));
-    return;
-  }
-  paused_ = paused;
-}
-
-namespace {
-
-// Originally from remoting/codec/scoped_vpx_codec.h.
-// TODO(mcasas): Refactor into a common location.
-struct VpxCodecDeleter {
-  void operator()(vpx_codec_ctx_t* codec) {
-    if (!codec)
-      return;
-    vpx_codec_err_t ret = vpx_codec_destroy(codec);
-    CHECK_EQ(ret, VPX_CODEC_OK);
-    delete codec;
-  }
-};
-typedef std::unique_ptr<vpx_codec_ctx_t, VpxCodecDeleter> ScopedVpxCodecCtxPtr;
-
-static void OnFrameEncodeCompleted(
+// static
+void VideoTrackRecorder::Encoder::OnFrameEncodeCompleted(
     const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_cb,
     const media::WebmMuxer::VideoParameters& params,
     std::unique_ptr<std::string> data,
     std::unique_ptr<std::string> alpha_data,
     base::TimeTicks capture_timestamp,
     bool keyframe) {
   DVLOG(1) << (keyframe ? "" : "non ") << "keyframe "<< data->length() << "B, "
            << capture_timestamp << " ms";
   on_encoded_video_cb.Run(params, std::move(data), std::move(alpha_data),
                           capture_timestamp, keyframe);
 }
 
-static int GetNumberOfThreadsForEncoding() {
-  // 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.
-  return std::min(8, (base::SysInfo::NumberOfProcessors() + 1) / 2);
+void VideoTrackRecorder::Encoder::SetPaused(bool paused) {
+  if (!encoding_task_runner_->BelongsToCurrentThread()) {
+    encoding_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&Encoder::SetPaused, this, paused));
+    return;
+  }
+  paused_ = paused;
 }
 
-// Class encapsulating VideoEncodeAccelerator interactions.
-// This class is created and destroyed in its owner thread. All other methods
-// operate on the task runner pointed by GpuFactories.
-class VEAEncoder final : public VideoTrackRecorder::Encoder,
-                         public media::VideoEncodeAccelerator::Client {
- public:
-  VEAEncoder(
-      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-      int32_t bits_per_second,
-      media::VideoCodecProfile codec,
-      const gfx::Size& size);
-
-  // media::VideoEncodeAccelerator::Client implementation.
-  void RequireBitstreamBuffers(unsigned int input_count,
-                               const gfx::Size& input_coded_size,
-                               size_t output_buffer_size) override;
-  void BitstreamBufferReady(int32_t bitstream_buffer_id,
-                            size_t payload_size,
-                            bool key_frame,
-                            base::TimeDelta timestamp) override;
-  void NotifyError(media::VideoEncodeAccelerator::Error error) override;
-
- private:
-  using VideoFrameAndTimestamp =
-      std::pair<scoped_refptr<media::VideoFrame>, base::TimeTicks>;
-  using VideoParamsAndTimestamp =
-      std::pair<media::WebmMuxer::VideoParameters, base::TimeTicks>;
-
-  void UseOutputBitstreamBufferId(int32_t bitstream_buffer_id);
-  void FrameFinished(std::unique_ptr<base::SharedMemory> shm);
-
-  // VideoTrackRecorder::Encoder implementation.
-  ~VEAEncoder() override;
-  void EncodeOnEncodingTaskRunner(scoped_refptr<VideoFrame> frame,
-                                  base::TimeTicks capture_timestamp) override;
-
-  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size);
-
-  void DestroyOnEncodingTaskRunner(base::WaitableEvent* async_waiter);
-
-  media::GpuVideoAcceleratorFactories* const gpu_factories_;
-
-  const media::VideoCodecProfile codec_;
-
-  // The underlying VEA to perform encoding on.
-  std::unique_ptr<media::VideoEncodeAccelerator> video_encoder_;
-
-  // Shared memory buffers for output with the VEA.
-  std::vector<std::unique_ptr<base::SharedMemory>> output_buffers_;
-
-  // Shared memory buffers for output with the VEA as FIFO.
-  std::queue<std::unique_ptr<base::SharedMemory>> input_buffers_;
-
-  // Tracks error status.
-  bool error_notified_;
-
-  // Tracks the last frame that we delay the encode.
-  std::unique_ptr<VideoFrameAndTimestamp> last_frame_;
-
-  // Size used to initialize encoder.
-  gfx::Size input_visible_size_;
-
-  // Coded size that encoder requests as input.
-  gfx::Size vea_requested_input_coded_size_;
-
-  // Frames and corresponding timestamps in encode as FIFO.
-  std::queue<VideoParamsAndTimestamp> frames_in_encode_;
-};
-
-// Class encapsulating all libvpx interactions for VP8/VP9 encoding.
-class VpxEncoder final : public VideoTrackRecorder::Encoder {
- public:
-  static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
-                              ScopedVpxCodecCtxPtr encoder);
-
-  VpxEncoder(
-      bool use_vp9,
-      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-      int32_t bits_per_second);
-
- private:
-  // VideoTrackRecorder::Encoder implementation.
-  ~VpxEncoder() override;
-  void EncodeOnEncodingTaskRunner(scoped_refptr<VideoFrame> frame,
-                                  base::TimeTicks capture_timestamp) override;
-  bool CanEncodeAlphaChannel() override { return true; }
-
-  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size,
-                                            vpx_codec_enc_cfg_t* codec_config,
-                                            ScopedVpxCodecCtxPtr* encoder);
-  void DoEncode(vpx_codec_ctx_t* const encoder,
-                const gfx::Size& frame_size,
-                uint8_t* const data,
-                uint8_t* const y_plane,
-                int y_stride,
-                uint8_t* const u_plane,
-                int u_stride,
-                uint8_t* const v_plane,
-                int v_stride,
-                const base::TimeDelta& duration,
-                bool force_keyframe,
-                std::string* const output_data,
-                bool* const keyframe);
-
-  // Returns true if |codec_config| has been filled in at least once.
-  bool IsInitialized(const vpx_codec_enc_cfg_t& codec_config) const;
-
-  // Estimate the frame duration from |frame| and |last_frame_timestamp_|.
-  base::TimeDelta EstimateFrameDuration(const scoped_refptr<VideoFrame>& frame);
-
-  // Force usage of VP9 for encoding, instead of VP8 which is the default.
-  const bool use_vp9_;
-
-  // VPx internal objects: configuration and encoder. |encoder_| is a special
-  // scoped pointer to guarantee proper destruction, particularly when
-  // reconfiguring due to parameters change. Only used on |encoding_thread_|.
-  vpx_codec_enc_cfg_t codec_config_;
-  ScopedVpxCodecCtxPtr encoder_;
-
-  vpx_codec_enc_cfg_t alpha_codec_config_;
-  ScopedVpxCodecCtxPtr alpha_encoder_;
-
-  std::vector<uint8_t> alpha_dummy_planes_;
-  size_t v_plane_offset_;
-  size_t u_plane_stride_;
-  size_t v_plane_stride_;
-  bool last_frame_had_alpha_ = false;
-
-  // The |VideoFrame::timestamp()| of the last encoded frame.  This is used to
-  // predict the duration of the next frame. Only used on |encoding_thread_|.
-  base::TimeDelta last_frame_timestamp_;
-
-  DISALLOW_COPY_AND_ASSIGN(VpxEncoder);
-};
-
-#if BUILDFLAG(RTC_USE_H264)
-
-struct ISVCEncoderDeleter {
-  void operator()(ISVCEncoder* codec) {
-    if (!codec)
-      return;
-    const int uninit_ret = codec->Uninitialize();
-    CHECK_EQ(cmResultSuccess, uninit_ret);
-    WelsDestroySVCEncoder(codec);
-  }
-};
-typedef std::unique_ptr<ISVCEncoder, ISVCEncoderDeleter> ScopedISVCEncoderPtr;
-
-// Class encapsulating all openh264 interactions for H264 encoding.
-class H264Encoder final : public VideoTrackRecorder::Encoder {
- public:
-  static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
-                              ScopedISVCEncoderPtr encoder);
-
-  H264Encoder(
-      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-      int32_t bits_per_second);
-
- private:
-  // VideoTrackRecorder::Encoder implementation.
-  ~H264Encoder() override;
-  void EncodeOnEncodingTaskRunner(scoped_refptr<VideoFrame> frame,
-                              base::TimeTicks capture_timestamp) override;
-
-  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size);
-
-  // |openh264_encoder_| is a special scoped pointer to guarantee proper
-  // destruction, also when reconfiguring due to parameters change. Only used on
-  // |encoding_thread_|.
-  gfx::Size configured_size_;
-  ScopedISVCEncoderPtr openh264_encoder_;
-
-  // The |VideoFrame::timestamp()| of the first received frame. Only used on
-  // |encoding_thread_|.
-  base::TimeTicks first_frame_timestamp_;
-
-  DISALLOW_COPY_AND_ASSIGN(H264Encoder);
-};
-
-#endif  // #if BUILDFLAG(RTC_USE_H264)
-
-VEAEncoder::VEAEncoder(
-    const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-    int32_t bits_per_second,
-    media::VideoCodecProfile codec,
-    const gfx::Size& size)
-    : Encoder(on_encoded_video_callback,
-              bits_per_second > 0 ? bits_per_second
-                                  : size.GetArea() * kVEADefaultBitratePerPixel,
-              RenderThreadImpl::current()->GetGpuFactories()->GetTaskRunner()),
-      gpu_factories_(RenderThreadImpl::current()->GetGpuFactories()),
-      codec_(codec),
-      error_notified_(false) {
-  DCHECK(gpu_factories_);
-  DCHECK_GE(size.width(), kVEAEncoderMinResolutionWidth);
-  DCHECK_GE(size.height(), kVEAEncoderMinResolutionHeight);
-
-  encoding_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VEAEncoder::ConfigureEncoderOnEncodingTaskRunner,
-                            this, size));
-}
-
-VEAEncoder::~VEAEncoder() {
-  base::WaitableEvent release_waiter(
-      base::WaitableEvent::ResetPolicy::MANUAL,
-      base::WaitableEvent::InitialState::NOT_SIGNALED);
-  // base::Unretained is safe because the class will be alive until
-  // |release_waiter| is signaled.
-  // TODO(emircan): Consider refactoring media::VideoEncodeAccelerator to avoid
-  // using naked pointers and using DeleteSoon() here, see
-  // http://crbug.com/701627.
-  // It is currently unsafe because |video_encoder_| might be in use on another
-  // function on |encoding_task_runner_|, see http://crbug.com/701030.
-  encoding_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&VEAEncoder::DestroyOnEncodingTaskRunner,
-                            base::Unretained(this), &release_waiter));
-  release_waiter.Wait();
-}
-
-void VEAEncoder::RequireBitstreamBuffers(unsigned int /*input_count*/,
-                                         const gfx::Size& input_coded_size,
-                                         size_t output_buffer_size) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  vea_requested_input_coded_size_ = input_coded_size;
-  output_buffers_.clear();
-  std::queue<std::unique_ptr<base::SharedMemory>>().swap(input_buffers_);
-
-  for (int i = 0; i < kVEAEncoderOutputBufferCount; ++i) {
-    std::unique_ptr<base::SharedMemory> shm =
-        gpu_factories_->CreateSharedMemory(output_buffer_size);
-    if (shm)
-      output_buffers_.push_back(base::WrapUnique(shm.release()));
-  }
-
-  for (size_t i = 0; i < output_buffers_.size(); ++i)
-    UseOutputBitstreamBufferId(i);
-}
-
-void VEAEncoder::BitstreamBufferReady(int32_t bitstream_buffer_id,
-                                      size_t payload_size,
-                                      bool keyframe,
-                                      base::TimeDelta timestamp) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  base::SharedMemory* output_buffer =
-      output_buffers_[bitstream_buffer_id].get();
-
-  std::unique_ptr<std::string> data(new std::string);
-  data->append(reinterpret_cast<char*>(output_buffer->memory()), payload_size);
-
-  const auto front_frame = frames_in_encode_.front();
-  frames_in_encode_.pop();
-  origin_task_runner_->PostTask(
-      FROM_HERE, base::Bind(OnFrameEncodeCompleted, on_encoded_video_callback_,
-                            front_frame.first, base::Passed(&data), nullptr,
-                            front_frame.second, keyframe));
-  UseOutputBitstreamBufferId(bitstream_buffer_id);
-}
-
-void VEAEncoder::NotifyError(media::VideoEncodeAccelerator::Error error) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  // TODO(emircan): Notify the owner via a callback.
-  error_notified_ = true;
-}
-
-void VEAEncoder::UseOutputBitstreamBufferId(int32_t bitstream_buffer_id) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  video_encoder_->UseOutputBitstreamBuffer(media::BitstreamBuffer(
-      bitstream_buffer_id, output_buffers_[bitstream_buffer_id]->handle(),
-      output_buffers_[bitstream_buffer_id]->mapped_size()));
-}
-
-void VEAEncoder::FrameFinished(std::unique_ptr<base::SharedMemory> shm) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  input_buffers_.push(std::move(shm));
-}
-
-void VEAEncoder::EncodeOnEncodingTaskRunner(
-   scoped_refptr<VideoFrame> frame,
-    base::TimeTicks capture_timestamp) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  if (input_visible_size_ != frame->visible_rect().size() && video_encoder_)
-    video_encoder_.reset();
-
-  if (!video_encoder_)
-    ConfigureEncoderOnEncodingTaskRunner(frame->visible_rect().size());
-
-  if (error_notified_) {
-    DVLOG(3) << "An error occurred in VEA encoder";
-    return;
-  }
-
-  // Drop frames if there is no output buffers available.
-  if (output_buffers_.empty()) {
-    // TODO(emircan): Investigate if resetting encoder would help.
-    DVLOG(3) << "Might drop frame.";
-    last_frame_.reset(
-        new std::pair<scoped_refptr<VideoFrame>, base::TimeTicks>(
-            frame, capture_timestamp));
-    return;
-  }
-
-  // If first frame hasn't been encoded, do it first.
-  if (last_frame_) {
-    std::unique_ptr<VideoFrameAndTimestamp> last_frame(last_frame_.release());
-    EncodeOnEncodingTaskRunner(last_frame->first, last_frame->second);
-  }
-
-  // Lower resolutions may fall back to SW encoder in some platforms, i.e. Mac.
-  // In that case, the encoder expects more frames before returning result.
-  // Therefore, a copy is necessary to release the current frame.
-  // Only STORAGE_SHMEM backed frames can be shared with GPU process, therefore
-  // a copy is required for other storage types.
-  scoped_refptr<media::VideoFrame> video_frame = frame;
-  if (video_frame->storage_type() != VideoFrame::STORAGE_SHMEM ||
-      vea_requested_input_coded_size_ != frame->coded_size() ||
-      input_visible_size_.width() < kVEAEncoderMinResolutionWidth ||
-      input_visible_size_.height() < kVEAEncoderMinResolutionHeight) {
-    // Create SharedMemory backed input buffers as necessary. These SharedMemory
-    // instances will be shared with GPU process.
-    std::unique_ptr<base::SharedMemory> input_buffer;
-    const size_t desired_mapped_size = media::VideoFrame::AllocationSize(
-        media::PIXEL_FORMAT_I420, vea_requested_input_coded_size_);
-    if (input_buffers_.empty()) {
-      input_buffer = gpu_factories_->CreateSharedMemory(desired_mapped_size);
-    } else {
-      do {
-        input_buffer = std::move(input_buffers_.front());
-        input_buffers_.pop();
-      } while (!input_buffers_.empty() &&
-               input_buffer->mapped_size() < desired_mapped_size);
-      if (!input_buffer || input_buffer->mapped_size() < desired_mapped_size)
-        return;
-    }
-
-    video_frame = media::VideoFrame::WrapExternalSharedMemory(
-        media::PIXEL_FORMAT_I420, vea_requested_input_coded_size_,
-        gfx::Rect(input_visible_size_), input_visible_size_,
-        reinterpret_cast<uint8_t*>(input_buffer->memory()),
-        input_buffer->mapped_size(), input_buffer->handle(), 0,
-        frame->timestamp());
-    video_frame->AddDestructionObserver(media::BindToCurrentLoop(
-        base::Bind(&VEAEncoder::FrameFinished, this,
-                   base::Passed(std::move(input_buffer)))));
-    libyuv::I420Copy(frame->visible_data(media::VideoFrame::kYPlane),
-                     frame->stride(media::VideoFrame::kYPlane),
-                     frame->visible_data(media::VideoFrame::kUPlane),
-                     frame->stride(media::VideoFrame::kUPlane),
-                     frame->visible_data(media::VideoFrame::kVPlane),
-                     frame->stride(media::VideoFrame::kVPlane),
-                     video_frame->visible_data(media::VideoFrame::kYPlane),
-                     video_frame->stride(media::VideoFrame::kYPlane),
-                     video_frame->visible_data(media::VideoFrame::kUPlane),
-                     video_frame->stride(media::VideoFrame::kUPlane),
-                     video_frame->visible_data(media::VideoFrame::kVPlane),
-                     video_frame->stride(media::VideoFrame::kVPlane),
-                     input_visible_size_.width(), input_visible_size_.height());
-  }
-  frames_in_encode_.push(std::make_pair(
-      media::WebmMuxer::VideoParameters(frame), capture_timestamp));
-
-  video_encoder_->Encode(video_frame, false);
-}
-
-void VEAEncoder::ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) {
-  DVLOG(3) << __func__;
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  DCHECK(gpu_factories_->GetTaskRunner()->BelongsToCurrentThread());
-  DCHECK_GT(bits_per_second_, 0);
-
-  input_visible_size_ = size;
-  video_encoder_ = gpu_factories_->CreateVideoEncodeAccelerator();
-  if (!video_encoder_ ||
-      !video_encoder_->Initialize(media::PIXEL_FORMAT_I420, input_visible_size_,
-                                  codec_, bits_per_second_, this)) {
-    NotifyError(media::VideoEncodeAccelerator::kPlatformFailureError);
-  }
-}
-
-void VEAEncoder::DestroyOnEncodingTaskRunner(
-    base::WaitableEvent* async_waiter) {
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  video_encoder_.reset();
-  async_waiter->Signal();
+bool VideoTrackRecorder::Encoder::CanEncodeAlphaChannel() {
+  return false;
 }
 
 // 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.
-}
-
-VpxEncoder::VpxEncoder(
-    bool use_vp9,
-    const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-    int32_t bits_per_second)
-    : Encoder(on_encoded_video_callback, bits_per_second),
-      use_vp9_(use_vp9) {
-  codec_config_.g_timebase.den = 0;  // Not initialized.
-  alpha_codec_config_.g_timebase.den = 0;  // Not initialized.
-  DCHECK(encoding_thread_->IsRunning());
-}
-
-VpxEncoder::~VpxEncoder() {
-  main_task_runner_->PostTask(FROM_HERE,
-                              base::Bind(&VpxEncoder::ShutdownEncoder,
-                                         base::Passed(&encoding_thread_),
-                                         base::Passed(&encoder_)));
-}
-
-void VpxEncoder::EncodeOnEncodingTaskRunner(
-    scoped_refptr<VideoFrame> frame,
-    base::TimeTicks capture_timestamp) {
-  TRACE_EVENT0("video", "VpxEncoder::EncodeOnEncodingTaskRunner");
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  const gfx::Size frame_size = frame->visible_rect().size();
-  const base::TimeDelta duration = EstimateFrameDuration(frame);
-  const media::WebmMuxer::VideoParameters video_params(frame);
-
-  if (!IsInitialized(codec_config_) ||
-      gfx::Size(codec_config_.g_w, codec_config_.g_h) != frame_size) {
-    ConfigureEncoderOnEncodingTaskRunner(frame_size, &codec_config_, &encoder_);
-  }
-
-  const bool frame_has_alpha = frame->format() == media::PIXEL_FORMAT_YV12A;
-  if (frame_has_alpha && (!IsInitialized(alpha_codec_config_) ||
-                          gfx::Size(alpha_codec_config_.g_w,
-                                    alpha_codec_config_.g_h) != frame_size)) {
-    ConfigureEncoderOnEncodingTaskRunner(frame_size, &alpha_codec_config_,
-                                         &alpha_encoder_);
-    u_plane_stride_ = media::VideoFrame::RowBytes(
-        VideoFrame::kUPlane, frame->format(), frame_size.width());
-    v_plane_stride_ = media::VideoFrame::RowBytes(
-        VideoFrame::kVPlane, frame->format(), frame_size.width());
-    v_plane_offset_ = media::VideoFrame::PlaneSize(
-                          frame->format(), VideoFrame::kUPlane, frame_size)
-                          .GetArea();
-    alpha_dummy_planes_.resize(
-        v_plane_offset_ + media::VideoFrame::PlaneSize(
-                              frame->format(), VideoFrame::kVPlane, frame_size)
-                              .GetArea());
-    // It is more expensive to encode 0x00, so use 0x80 instead.
-    std::fill(alpha_dummy_planes_.begin(), alpha_dummy_planes_.end(), 0x80);
-  }
-  // If we introduced a new alpha frame, force keyframe.
-  const bool force_keyframe = frame_has_alpha && !last_frame_had_alpha_;
-  last_frame_had_alpha_ = frame_has_alpha;
-
-  std::unique_ptr<std::string> data(new std::string);
-  bool keyframe = false;
-  DoEncode(encoder_.get(), frame_size, frame->data(VideoFrame::kYPlane),
-           frame->visible_data(VideoFrame::kYPlane),
-           frame->stride(VideoFrame::kYPlane),
-           frame->visible_data(VideoFrame::kUPlane),
-           frame->stride(VideoFrame::kUPlane),
-           frame->visible_data(VideoFrame::kVPlane),
-           frame->stride(VideoFrame::kVPlane), duration, force_keyframe,
-           data.get(), &keyframe);
-
-  std::unique_ptr<std::string> alpha_data(new std::string);
-  if (frame_has_alpha) {
-    bool alpha_keyframe = false;
-    DoEncode(alpha_encoder_.get(), frame_size, frame->data(VideoFrame::kAPlane),
-             frame->visible_data(VideoFrame::kAPlane),
-             frame->stride(VideoFrame::kAPlane), alpha_dummy_planes_.data(),
-             u_plane_stride_, alpha_dummy_planes_.data() + v_plane_offset_,
-             v_plane_stride_, duration, keyframe, alpha_data.get(),
-             &alpha_keyframe);
-    DCHECK_EQ(keyframe, alpha_keyframe);
-  }
-  frame = nullptr;
-
-  origin_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(OnFrameEncodeCompleted, on_encoded_video_callback_,
-                 video_params, base::Passed(&data), base::Passed(&alpha_data),
-                 capture_timestamp, keyframe));
-}
-
-void VpxEncoder::DoEncode(vpx_codec_ctx_t* const encoder,
-                          const gfx::Size& frame_size,
-                          uint8_t* const data,
-                          uint8_t* const y_plane,
-                          int y_stride,
-                          uint8_t* const u_plane,
-                          int u_stride,
-                          uint8_t* const v_plane,
-                          int v_stride,
-                          const base::TimeDelta& duration,
-                          bool force_keyframe,
-                          std::string* const output_data,
-                          bool* const keyframe) {
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  vpx_image_t vpx_image;
-  vpx_image_t* const result =
-      vpx_img_wrap(&vpx_image, VPX_IMG_FMT_I420, frame_size.width(),
-                   frame_size.height(), 1 /* align */, data);
-  DCHECK_EQ(result, &vpx_image);
-  vpx_image.planes[VPX_PLANE_Y] = y_plane;
-  vpx_image.planes[VPX_PLANE_U] = u_plane;
-  vpx_image.planes[VPX_PLANE_V] = v_plane;
-  vpx_image.stride[VPX_PLANE_Y] = y_stride;
-  vpx_image.stride[VPX_PLANE_U] = u_stride;
-  vpx_image.stride[VPX_PLANE_V] = v_stride;
-
-  const vpx_codec_flags_t flags = force_keyframe ? VPX_EFLAG_FORCE_KF : 0;
-  // Encode the frame.  The presentation time stamp argument here is fixed to
-  // zero to force the encoder to base its single-frame bandwidth calculations
-  // entirely on |predicted_frame_duration|.
-  const vpx_codec_err_t ret =
-      vpx_codec_encode(encoder, &vpx_image, 0 /* pts */,
-                       duration.InMicroseconds(), flags, VPX_DL_REALTIME);
-  DCHECK_EQ(ret, VPX_CODEC_OK)
-      << vpx_codec_err_to_string(ret) << ", #" << vpx_codec_error(encoder)
-      << " -" << vpx_codec_error_detail(encoder);
-
-  *keyframe = false;
-  vpx_codec_iter_t iter = NULL;
-  const vpx_codec_cx_pkt_t* pkt = NULL;
-  while ((pkt = vpx_codec_get_cx_data(encoder, &iter)) != NULL) {
-    if (pkt->kind != VPX_CODEC_CX_FRAME_PKT)
-      continue;
-    output_data->assign(static_cast<char*>(pkt->data.frame.buf),
-                        pkt->data.frame.sz);
-    *keyframe = (pkt->data.frame.flags & VPX_FRAME_IS_KEY) != 0;
-    break;
-  }
-}
-
-void VpxEncoder::ConfigureEncoderOnEncodingTaskRunner(
-    const gfx::Size& size,
-    vpx_codec_enc_cfg_t* codec_config,
-    ScopedVpxCodecCtxPtr* encoder) {
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  if (IsInitialized(*codec_config)) {
-    // 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();
-  }
-
-  const vpx_codec_iface_t* codec_interface =
-      use_vp9_ ? vpx_codec_vp9_cx() : vpx_codec_vp8_cx();
-  vpx_codec_err_t result = vpx_codec_enc_config_default(
-      codec_interface, codec_config, 0 /* reserved */);
-  DCHECK_EQ(VPX_CODEC_OK, result);
-
-  DCHECK_EQ(320u, codec_config->g_w);
-  DCHECK_EQ(240u, codec_config->g_h);
-  DCHECK_EQ(256u, codec_config->rc_target_bitrate);
-  // Use the selected bitrate or adjust default bit rate to account for the
-  // actual size.  Note: |rc_target_bitrate| units are kbit per second.
-  if (bits_per_second_ > 0) {
-    codec_config->rc_target_bitrate = bits_per_second_ / 1000;
-  } else {
-    codec_config->rc_target_bitrate = size.GetArea() *
-                                      codec_config->rc_target_bitrate /
-                                      codec_config->g_w / codec_config->g_h;
-  }
-  // Both VP8/VP9 configuration should be Variable BitRate by default.
-  DCHECK_EQ(VPX_VBR, codec_config->rc_end_usage);
-  if (use_vp9_) {
-    // Number of frames to consume before producing output.
-    codec_config->g_lag_in_frames = 0;
-
-    // DCHECK that the profile selected by default is I420 (magic number 0).
-    DCHECK_EQ(0u, codec_config->g_profile);
-  } else {
-    // VP8 always produces frames instantaneously.
-    DCHECK_EQ(0u, codec_config->g_lag_in_frames);
-  }
-
-  DCHECK(size.width());
-  DCHECK(size.height());
-  codec_config->g_w = size.width();
-  codec_config->g_h = size.height();
-  codec_config->g_pass = VPX_RC_ONE_PASS;
-
-  // Timebase is the smallest interval used by the stream, can be set to the
-  // frame rate or to e.g. microseconds.
-  codec_config->g_timebase.num = 1;
-  codec_config->g_timebase.den = base::Time::kMicrosecondsPerSecond;
-
-  // Let the encoder decide where to place the Keyframes, between min and max.
-  // In VPX_KF_AUTO mode libvpx will sometimes emit keyframes regardless of min/
-  // max distance out of necessity.
-  // Note that due to http://crbug.com/440223, it might be necessary to force a
-  // key frame after 10,000frames since decoding fails after 30,000 non-key
-  // frames.
-  // Forcing a keyframe in regular intervals also allows seeking in the
-  // resulting recording with decent performance.
-  codec_config->kf_mode = VPX_KF_AUTO;
-  codec_config->kf_min_dist = 0;
-  codec_config->kf_max_dist = 100;
-
-  codec_config->g_threads = GetNumberOfThreadsForEncoding();
-
-  // Number of frames to consume before producing output.
-  codec_config->g_lag_in_frames = 0;
-
-  encoder->reset(new vpx_codec_ctx_t);
-  const vpx_codec_err_t ret = vpx_codec_enc_init(
-      encoder->get(), codec_interface, codec_config, 0 /* flags */);
-  DCHECK_EQ(VPX_CODEC_OK, ret);
-
-  if (use_vp9_) {
-    // Values of VP8E_SET_CPUUSED greater than 0 will increase encoder speed at
-    // 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 VpxEncoder::IsInitialized(const vpx_codec_enc_cfg_t& codec_config) const {
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  return codec_config.g_timebase.den != 0;
-}
-
-base::TimeDelta VpxEncoder::EstimateFrameDuration(
-    const scoped_refptr<VideoFrame>& frame) {
-  DCHECK(encoding_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));
-}
-
-#if BUILDFLAG(RTC_USE_H264)
-
-// static
-void H264Encoder::ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
-                                  ScopedISVCEncoderPtr encoder) {
-  DCHECK(encoding_thread->IsRunning());
-  encoding_thread->Stop();
-  // Both |encoding_thread| and |encoder| will be destroyed at end-of-scope.
-}
-
-H264Encoder::H264Encoder(
-    const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
-    int32_t bits_per_second)
-    : Encoder(on_encoded_video_callback, bits_per_second) {
-  DCHECK(encoding_thread_->IsRunning());
-}
-
-H264Encoder::~H264Encoder() {
-  main_task_runner_->PostTask(FROM_HERE,
-                              base::Bind(&H264Encoder::ShutdownEncoder,
-                                         base::Passed(&encoding_thread_),
-                                         base::Passed(&openh264_encoder_)));
-}
-
-void H264Encoder::EncodeOnEncodingTaskRunner(
-    scoped_refptr<VideoFrame> frame,
-    base::TimeTicks capture_timestamp) {
-  TRACE_EVENT0("video", "H264Encoder::EncodeOnEncodingTaskRunner");
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-
-  const gfx::Size frame_size = frame->visible_rect().size();
-  if (!openh264_encoder_ || configured_size_ != frame_size) {
-    ConfigureEncoderOnEncodingTaskRunner(frame_size);
-    first_frame_timestamp_ = capture_timestamp;
-  }
-
-  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] = frame->stride(VideoFrame::kYPlane);
-  picture.iStride[1] = frame->stride(VideoFrame::kUPlane);
-  picture.iStride[2] = frame->stride(VideoFrame::kVPlane);
-  picture.pData[0] = frame->visible_data(VideoFrame::kYPlane);
-  picture.pData[1] = frame->visible_data(VideoFrame::kUPlane);
-  picture.pData[2] = frame->visible_data(VideoFrame::kVPlane);
-
-  SFrameBSInfo info = {};
-  if (openh264_encoder_->EncodeFrame(&picture, &info) != cmResultSuccess) {
-    NOTREACHED() << "OpenH264 encoding failed";
-    return;
-  }
-  const media::WebmMuxer::VideoParameters video_params(frame);
-  frame = nullptr;
-
-  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) {
-      // The following DCHECKs make sure that the header of each NAL unit is OK.
-      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 NAL 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_,
-                            video_params, base::Passed(&data), nullptr,
-                            capture_timestamp, is_key_frame));
-}
-
-void H264Encoder::ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) {
-  DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  ISVCEncoder* temp_encoder = nullptr;
-  if (WelsCreateSVCEncoder(&temp_encoder) != 0) {
-    NOTREACHED() << "Failed to create OpenH264 encoder";
-    return;
-  }
-  openh264_encoder_.reset(temp_encoder);
-  configured_size_ = size;
-
-#if DCHECK_IS_ON()
-  int trace_level = WELS_LOG_INFO;
-  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;
-
-  DCHECK_EQ(AUTO_REF_PIC_COUNT, init_params.iNumRefFrame);
-  DCHECK(!init_params.bSimulcastAVC);
-
-  init_params.uiIntraPeriod = 100;  // Same as for VpxEncoder.
-  init_params.iPicWidth = size.width();
-  init_params.iPicHeight = size.height();
-
-  DCHECK_EQ(RC_QUALITY_MODE, init_params.iRCMode);
-  DCHECK_EQ(0, init_params.iPaddingFlag);
-  DCHECK_EQ(UNSPECIFIED_BIT_RATE, init_params.iTargetBitrate);
-  DCHECK_EQ(UNSPECIFIED_BIT_RATE, init_params.iMaxBitrate);
-  if (bits_per_second_ > 0) {
-    init_params.iRCMode = RC_BITRATE_MODE;
-    init_params.iTargetBitrate = bits_per_second_;
-  } else {
-    init_params.iRCMode = RC_OFF_MODE;
-  }
-
-  // Threading model: Set to 1 due to https://crbug.com/583348.
-  init_params.iMultipleThreadIdc = 1;
-
-  // TODO(mcasas): consider reducing complexity if there are few CPUs available.
-  init_params.iComplexityMode = MEDIUM_COMPLEXITY;
-  DCHECK(!init_params.bEnableDenoise);
-  DCHECK(init_params.bEnableFrameSkip);
-
-  // 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;
-
-  // When uiSliceMode = SM_FIXEDSLCNUM_SLICE, uiSliceNum = 0 means auto design
-  // it with cpu core number.
-  // TODO(sprang): Set to 0 when we understand why the rate controller borks
-  // when uiSliceNum > 1. See https://github.com/cisco/openh264/issues/2591
-  init_params.sSpatialLayers[0].sSliceArgument.uiSliceNum = 1;
-  init_params.sSpatialLayers[0].sSliceArgument.uiSliceMode =
-      SM_FIXEDSLCNUM_SLICE;
-
-  if (openh264_encoder_->InitializeExt(&init_params) != cmResultSuccess) {
-    NOTREACHED() << "Failed to initialize OpenH264 encoder";
-    return;
-  }
-
-  int pixel_format = EVideoFormatType::videoFormatI420;
-  openh264_encoder_->SetOption(ENCODER_OPTION_DATAFORMAT, &pixel_format);
-}
-#endif //#if BUILDFLAG(RTC_USE_H264)
-
-}  // anonymous namespace
-
-// static
 VideoTrackRecorder::CodecId VideoTrackRecorder::GetPreferredCodecId() {
   return GetCodecEnumerator()->GetPreferredCodecId();
 }
 
 VideoTrackRecorder::VideoTrackRecorder(
     CodecId codec,
     const blink::WebMediaStreamTrack& track,
     const OnEncodedVideoCB& on_encoded_video_callback,
     int32_t bits_per_second)
     : track_(track),
@@ skipping 92 matching lines @@
   if (paused_before_init_)
     encoder_->SetPaused(paused_before_init_);
 
   // StartFrameEncode() will be called on Render IO thread.
   MediaStreamVideoSink::ConnectToTrack(
       track_,
       base::Bind(&VideoTrackRecorder::Encoder::StartFrameEncode, encoder_),
       false);
 }
 
-bool VideoTrackRecorder::CanEncodeAlphaChannelForTesting() {
-  DCHECK(encoder_);
-  return encoder_->CanEncodeAlphaChannel();
-}
-
 }  // namespace content