MediaRecorderHandler (video part) and unittests

media/capture/webm_muxer.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 "media/capture/webm_muxer.h"
 
 #include <limits>
 
 #include "base/bind.h"
 #include "media/base/video_frame.h"
 
 namespace media {
 
 static double GetFrameRate(const scoped_refptr<VideoFrame>& video_frame) {
   double frame_rate = 0.0f;
   base::IgnoreResult(video_frame->metadata()->GetDouble(
       VideoFrameMetadata::FRAME_RATE, &frame_rate));
   return frame_rate;
 }
 
 WebmMuxer::WebmMuxer(const WriteDataCB& write_data_callback)
     : track_index_(0),
       write_data_callback_(write_data_callback),
       position_(0) {
-  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!write_data_callback_.is_null());
-  segment_.Init(this);
-  segment_.set_mode(mkvmuxer::Segment::kLive);
-  segment_.OutputCues(false);
-
-  mkvmuxer::SegmentInfo* const info = segment_.GetSegmentInfo();
-  info->set_writing_app("Chrome");
-  info->set_muxing_app("Chrome");
+  // Creation is done on a different thread than main activities.
+  io_thread_checker_.DetachFromThread();
 }
 
 WebmMuxer::~WebmMuxer() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  segment_.Finalize();
+  // No need to segment_.Finalize() since is not Seekable(), i.e. a live stream.

[miu, 2015/09/02 21:28:13]

What if this class is used to write a complete WebM file?  (I have been using it
for generating some sample videos.  BTW--I have bug fixes and will send you a CR
soon.)

[mcasas, 2015/09/04 02:16:30]

The mode (kLive/kFile) does not relate to File/Streaming, but 
to writing headers, cues and markers for seeking. Writing a Live 
WebM stream to file allows for playback -- I guess seeking 
might prove challenging.

[miu, 2015/09/04 21:48:52]

Would it break anything to include the call to Finalize()?  If not, please
include it.  I'm using it.  ;-)

[mcasas, 2015/09/05 02:43:01]

Done. Left the comment though.

 }
 
 void WebmMuxer::OnEncodedVideo(const scoped_refptr<VideoFrame>& video_frame,
                                const base::StringPiece& encoded_data,
                                base::TimeTicks timestamp,
                                bool is_key_frame) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+  DVLOG(1) << __FUNCTION__ << " - " << encoded_data.size() << "B";
+  DCHECK(io_thread_checker_.CalledOnValidThread());
   if (!track_index_) {
     // |track_index_|, cannot be zero (!), initialize WebmMuxer in that case.
     // http://www.matroska.org/technical/specs/index.html#Tracks
     AddVideoTrack(video_frame->visible_rect().size(),
                   GetFrameRate(video_frame));
     first_frame_timestamp_ = timestamp;
   }
   segment_.AddFrame(reinterpret_cast<const uint8_t*>(encoded_data.data()),
                     encoded_data.size(),
                     track_index_,
                     (timestamp - first_frame_timestamp_).InMilliseconds(),
                     is_key_frame);
 }
 
 void WebmMuxer::AddVideoTrack(const gfx::Size& frame_size, double frame_rate) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(io_thread_checker_.CalledOnValidThread());
+
+  segment_.Init(this);
+  segment_.set_mode(mkvmuxer::Segment::kLive);
+  segment_.OutputCues(false);
+
+  mkvmuxer::SegmentInfo* const info = segment_.GetSegmentInfo();
+  info->set_writing_app("Chrome");
+  info->set_muxing_app("Chrome");
+
   DCHECK_EQ(track_index_, 0u);
   track_index_ =
       segment_.AddVideoTrack(frame_size.width(), frame_size.height(), 0);
   DCHECK_GT(track_index_, 0u);
 
   mkvmuxer::VideoTrack* const video_track =
       reinterpret_cast<mkvmuxer::VideoTrack*>(
           segment_.GetTrackByNumber(track_index_));
   DCHECK(video_track);
   video_track->set_codec_id(mkvmuxer::Tracks::kVp8CodecId);
   DCHECK_EQ(video_track->crop_right(), 0ull);
   DCHECK_EQ(video_track->crop_left(), 0ull);
   DCHECK_EQ(video_track->crop_top(), 0ull);
   DCHECK_EQ(video_track->crop_bottom(), 0ull);
 
   video_track->set_frame_rate(frame_rate);
   video_track->set_default_duration(base::Time::kMicrosecondsPerSecond /
                                     frame_rate);
   // Segment's timestamps should be in milliseconds, DCHECK it. See
   // http://www.webmproject.org/docs/container/#muxer-guidelines
   DCHECK_EQ(segment_.GetSegmentInfo()->timecode_scale(), 1000000ull);
 }
 
 mkvmuxer::int32 WebmMuxer::Write(const void* buf, mkvmuxer::uint32 len) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(io_thread_checker_.CalledOnValidThread());
   DCHECK(buf);
   write_data_callback_.Run(base::StringPiece(reinterpret_cast<const char*>(buf),
                                              len));
   position_ += len;
   return 0;
 }
 
 mkvmuxer::int64 WebmMuxer::Position() const {
   return position_.ValueOrDie();
 }
 
 mkvmuxer::int32 WebmMuxer::Position(mkvmuxer::int64 position) {
   // The stream is not Seekable() so indicate we cannot set the position.
   return -1;
 }
 
 bool WebmMuxer::Seekable() const {
   return false;
 }
 
 void WebmMuxer::ElementStartNotify(mkvmuxer::uint64 element_id,
                                    mkvmuxer::int64 position) {
   // This method gets pinged before items are sent to |write_data_callback_|.
   DCHECK_GE(position, position_.ValueOrDefault(0))
       << "Can't go back in a live WebM stream.";
 }
 
 }  // namespace media