Support alpha channel recording for VPX in MediaRecorder

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"
@@ skipping 187 matching lines @@
         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 a ConfigureEncoderOnEncodingTaskRunner() 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.
+  // 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;
-  virtual void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) = 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_;
 
@@ skipping 36 matching lines @@
   }
 
   if (video_frame->HasTextures()) {
     main_task_runner_->PostTask(
         FROM_HERE, base::Bind(&Encoder::RetrieveFrameOnMainThread, this,
                               video_frame, capture_timestamp));
     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)
+  // Drop alpha channel if |encoder does not support it yet.

[vignesh, 2017/03/08 17:26:14]

Supernit: accidental |.

[emircan, 2017/03/08 23:53:58]

Done.

+  if (!CanEncodeAlphaChannel() && frame->format() == media::PIXEL_FORMAT_YV12A)
     frame = media::WrapAsI420VideoFrame(video_frame);
 
   encoding_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Encoder::EncodeOnEncodingTaskRunner, this, frame,
                             capture_timestamp));
 }
 
 void VideoTrackRecorder::Encoder::RetrieveFrameOnMainThread(
     const scoped_refptr<VideoFrame>& video_frame,
     base::TimeTicks capture_timestamp) {
@@ skipping 93 matching lines @@
     CHECK_EQ(ret, VPX_CODEC_OK);
     delete codec;
   }
 };
 typedef std::unique_ptr<vpx_codec_ctx_t, VpxCodecDeleter> ScopedVpxCodecCtxPtr;
 
 static void 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), capture_timestamp, keyframe);
+  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);
 }
 
 // Class encapsulating VideoEncodeAccelerator interactions.
@@ skipping 24 matching lines @@
   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) override;
+
+  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size);
 
   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_;
@@ skipping 26 matching lines @@
   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;
-  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) override;
+  bool CanEncodeAlphaChannel() override { return true; }
 
-  // Returns true if |codec_config_| has been filled in at least once.
-  bool IsInitialized() const;
+  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size,
+                                            vpx_codec_enc_cfg_t* codec_config,
+                                            ScopedVpxCodecCtxPtr* encoder);
+  void DoEncode(vpx_codec_ctx_t* 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* output_data,
+                bool* 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_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 {
@@ skipping 15 matching lines @@
 
   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) 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_;
@@ skipping 61 matching lines @@
   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),
+                            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;
@@ skipping 148 matching lines @@
                                          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();
-  if (!IsInitialized() ||
+  const base::TimeDelta duration = EstimateFrameDuration(frame);
+  const media::WebmMuxer::VideoParameters video_params(frame);
+  bool force_keyframe = false;
+
+  if (!IsInitialized(codec_config_) ||
       gfx::Size(codec_config_.g_w, codec_config_.g_h) != frame_size) {
-    ConfigureEncoderOnEncodingTaskRunner(frame_size);
-  }
+    ConfigureEncoderOnEncodingTaskRunner(frame_size, &codec_config_, &encoder_);
+  }
+
+  if (frame->format() == media::PIXEL_FORMAT_YV12A) {
+    if (!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_);
+      // It is more expensive to encode 0x00, so use 0x80 instead.

[vignesh, 2017/03/08 17:26:14]

nit: Move this line just above the std::fill below.

[emircan, 2017/03/08 23:53:58]

Done.

+      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());
+      std::fill(alpha_dummy_planes_.begin(), alpha_dummy_planes_.end(), 128);

[vignesh, 2017/03/08 17:26:14]

nit: can just use 0x80 here and avoid the mental conversion between comment and
code.

[emircan, 2017/03/08 23:53:58]

Done.

+    }
+    // If we introduced a new alpha frame, force keyframe on.
+    if (!last_frame_alpha_)
+      force_keyframe = true;
+    last_frame_alpha_ = true;
+  } else {
+    last_frame_alpha_ = false;
+  }
+
+  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->format() == media::PIXEL_FORMAT_YV12A) {
+    if (!IsInitialized(alpha_codec_config_) ||

[vignesh, 2017/03/08 17:26:14]

Why is this initialization block needed? The same thing happens above know?

[emircan, 2017/03/08 23:53:58]

Ouch, I missed it after a refactor. Removing this one.

+        gfx::Size(alpha_codec_config_.g_w, alpha_codec_config_.g_h) !=
+            frame_size) {
+      ConfigureEncoderOnEncodingTaskRunner(frame_size, &alpha_codec_config_,
+                                           &alpha_encoder_);
+      // It is more expensive to encode 0x00, so use 0x80 instead.
+      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());
+      std::fill(alpha_dummy_planes_.begin(), alpha_dummy_planes_.end(), 128);
+    }
+    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* encoder,

[vignesh, 2017/03/08 17:26:14]

nit: *const ?

[emircan, 2017/03/08 23:53:58]

Done.

+                          const gfx::Size& frame_size,
+                          uint8_t* const data,
+                          uint8_t* const y_plane,
+                          int y_stride,

[vignesh, 2017/03/08 17:26:14]

nit: const.

ditto for other strides & |force_keyframe|

[emircan, 2017/03/08 23:53:58]

AFAIK we dont use const for primitive function params in Chromium.

[vignesh, 2017/03/09 07:13:46]

Acknowledged.

+                          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* output_data,
+                          bool* keyframe) {

[vignesh, 2017/03/08 17:26:14]

nit: *const

Ditto in the line above.

[emircan, 2017/03/08 23:53:58]

Done.

+  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 */,
-                                           frame->data(VideoFrame::kYPlane));
+  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] = frame->visible_data(VideoFrame::kYPlane);
-  vpx_image.planes[VPX_PLANE_U] = frame->visible_data(VideoFrame::kUPlane);
-  vpx_image.planes[VPX_PLANE_V] = frame->visible_data(VideoFrame::kVPlane);
-  vpx_image.stride[VPX_PLANE_Y] = frame->stride(VideoFrame::kYPlane);
-  vpx_image.stride[VPX_PLANE_U] = frame->stride(VideoFrame::kUPlane);
-  vpx_image.stride[VPX_PLANE_V] = frame->stride(VideoFrame::kVPlane);
-
-  const base::TimeDelta duration = EstimateFrameDuration(frame);
+  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_.get(),
-                                               &vpx_image,
-                                               0  /* pts */,
-                                               duration.InMicroseconds(),
-                                               0 /* flags */,
-                                               VPX_DL_REALTIME);
-  DCHECK_EQ(ret, VPX_CODEC_OK) << vpx_codec_err_to_string(ret) << ", #"
-                               << vpx_codec_error(encoder_.get()) << " -"
-                               << vpx_codec_error_detail(encoder_.get());
-
-  const media::WebmMuxer::VideoParameters video_params(frame);
-  frame = nullptr;
-
-  std::unique_ptr<std::string> data(new std::string);
-  bool keyframe = false;
+  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_.get(), &iter)) != NULL) {
+  while ((pkt = vpx_codec_get_cx_data(encoder, &iter)) != NULL) {
     if (pkt->kind != VPX_CODEC_CX_FRAME_PKT)
       continue;
-    data->assign(static_cast<char*>(pkt->data.frame.buf), pkt->data.frame.sz);
-    keyframe = (pkt->data.frame.flags & VPX_FRAME_IS_KEY) != 0;
+    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;
   }
-  origin_task_runner_->PostTask(FROM_HERE,
-      base::Bind(OnFrameEncodeCompleted,
-                 on_encoded_video_callback_,
-                 video_params,
-                 base::Passed(&data),
-                 capture_timestamp,
-                 keyframe));
 }
 
-void VpxEncoder::ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size) {
+void VpxEncoder::ConfigureEncoderOnEncodingTaskRunner(
+    const gfx::Size& size,
+    vpx_codec_enc_cfg_t* codec_config,
+    ScopedVpxCodecCtxPtr* encoder) {
   DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  if (IsInitialized()) {
+  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}|.
+    // 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()
+             << gfx::Size(codec_config->g_w, codec_config->g_h).ToString()
              << " --> " << size.ToString() << (use_vp9_ ? " vp9" : " vp8");
-    encoder_.reset();
+    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 */);
+      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);
+  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;
+    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;
+    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);
+  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;
+    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);
+    DCHECK_EQ(0u, codec_config->g_profile);
   } else {
     // VP8 always produces frames instantaneously.
-    DCHECK_EQ(0u, codec_config_.g_lag_in_frames);
+    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;
+  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;
+  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->kf_mode = VPX_KF_AUTO;
+  codec_config->kf_min_dist = 0;
+  codec_config->kf_max_dist = 100;
 
-  codec_config_.g_threads = GetNumberOfThreadsForEncoding();
+  codec_config->g_threads = GetNumberOfThreadsForEncoding();
 
   // Number of frames to consume before producing output.
-  codec_config_.g_lag_in_frames = 0;
+  codec_config->g_lag_in_frames = 0;
 
-  DCHECK(!encoder_);
-  encoder_.reset(new vpx_codec_ctx_t);
+  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 */);
+      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);
+    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 {
+bool VpxEncoder::IsInitialized(const vpx_codec_enc_cfg_t& codec_config) const {
   DCHECK(encoding_task_runner_->BelongsToCurrentThread());
-  return codec_config_.g_timebase.den != 0;
+  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) ||
@@ skipping 87 matching lines @@
 
       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),
+                            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;
   }
@@ skipping 162 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