WebmMuxer-MediaRecorderHandler: thread hopping and data ownership

content/renderer/media/media_recorder_handler.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/media_recorder_handler.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/strings/stringprintf.h"

[miu, 2015/09/22 04:11:08]

Is this needed?  Doesn't seem to be used.

[mcasas, 2015/09/22 16:58:40]

Done.
(Argh! I've tried hard to remove unused includes but
missed this one).

 #include "content/renderer/media/video_track_recorder.h"
 #include "media/base/bind_to_current_loop.h"
+#include "media/base/video_frame.h"
 #include "media/capture/webm_muxer.h"
 #include "third_party/WebKit/public/platform/WebMediaRecorderHandlerClient.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 
 namespace content {
 
 MediaRecorderHandler::MediaRecorderHandler()
     : recording_(false), client_(nullptr), weak_factory_(this) {
   DVLOG(3) << __FUNCTION__;
 }
@@ skipping 31 matching lines @@
 bool MediaRecorderHandler::start() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!recording_);
   return start(0);
 }
 
 bool MediaRecorderHandler::start(int timeslice) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!recording_);
   DCHECK(!media_stream_.isNull());
+  DCHECK(!webm_muxer_);
 
-  webm_muxer_.reset(new media::WebmMuxer(media::BindToCurrentLoop(base::Bind(
-      &MediaRecorderHandler::WriteData, weak_factory_.GetWeakPtr()))));
-  DCHECK(webm_muxer_);
+  webm_muxer_.reset(new media::WebmMuxer(base::Bind(
+      &MediaRecorderHandler::WriteData, weak_factory_.GetWeakPtr())));
 
   blink::WebVector<blink::WebMediaStreamTrack> video_tracks;
   media_stream_.videoTracks(video_tracks);
 
   if (video_tracks.isEmpty()) {
     // TODO(mcasas): Add audio_tracks and update the code in this function
     // correspondingly, see http://crbug.com/528519. As of now, only video
     // tracks are supported.
     LOG(WARNING) << "Recording no video tracks is not implemented";
     return false;
   }
   // TODO(mcasas): The muxer API supports only one video track. Extend it to
   // several video tracks, see http://crbug.com/528523.
   LOG_IF(WARNING, video_tracks.size() > 1u) << "Recording multiple video"
       << " tracks is not implemented.  Only recording first video track.";
   const blink::WebMediaStreamTrack& video_track = video_tracks[0];
   if (video_track.isNull())
     return false;
 
   const VideoTrackRecorder::OnEncodedVideoCB on_encoded_video_cb =
-      base::Bind(&media::WebmMuxer::OnEncodedVideo,
-                 base::Unretained(webm_muxer_.get()));
+      media::BindToCurrentLoop(base::Bind(&MediaRecorderHandler::OnEncodedVideo,
+                                          weak_factory_.GetWeakPtr()));
 
   video_recorders_.push_back(new VideoTrackRecorder(video_track,
                                                     on_encoded_video_cb));
 
   recording_ = true;
   return true;
 }
 
 void MediaRecorderHandler::stop() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(recording_);
 
   recording_ = false;
   video_recorders_.clear();
   webm_muxer_.reset(NULL);

[miu, 2015/09/22 04:11:08]

nit: no arg needed to reset()

[mcasas, 2015/09/22 16:58:40]

Done.

 }
 
 void MediaRecorderHandler::pause() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(recording_);
   recording_ = false;
   NOTIMPLEMENTED();
 }
 
 void MediaRecorderHandler::resume() {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!recording_);
   recording_ = true;
   NOTIMPLEMENTED();
 }
 
-void MediaRecorderHandler::WriteData(const base::StringPiece& data) {
+void MediaRecorderHandler::OnEncodedVideo(
+    const scoped_refptr<media::VideoFrame>& video_frame,
+    scoped_ptr<std::string> encoded_data,
+    base::TimeTicks timestamp,
+    bool is_key_frame) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
-  client_->writeData(data.data(), data.size(), false  /* lastInSlice */);
+  if (webm_muxer_) {
+    webm_muxer_->OnEncodedVideo(video_frame, encoded_data.Pass(), timestamp,
+                                is_key_frame);
+  }
+}
+
+
+void MediaRecorderHandler::WriteData(scoped_ptr<std::string> data) {
+  DCHECK(main_render_thread_checker_.CalledOnValidThread());
+  client_->writeData(data->data(), data->length(), false  /* lastInSlice */);
 }
 
 void MediaRecorderHandler::OnVideoFrameForTesting(
     const scoped_refptr<media::VideoFrame>& frame,
     const base::TimeTicks& timestamp) {
   for (auto* recorder : video_recorders_)
     recorder->OnVideoFrameForTesting(frame, timestamp);
 }
 
 }  // namespace content