MediaStream Recorder: Support VP9 encoder

media/capture/webm_muxer.h

 // 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.
 
 #ifndef MEDIA_FILTERS_LIBWEBM_MUXER_H_
 #define MEDIA_FILTERS_LIBWEBM_MUXER_H_
 
 #include <set>
 
 #include "base/callback.h"
@@ skipping 22 matching lines @@
 // WebmMuxer is designed for single thread use throughout.
 // [1] http://www.webmproject.org/docs/container/
 // [2] http://www.matroska.org/technical/specs/index.html
 // TODO(mcasas): Add support for Audio muxing.
 class MEDIA_EXPORT WebmMuxer : public NON_EXPORTED_BASE(mkvmuxer::IMkvWriter) {
  public:
   // Callback to be called when WebmMuxer is ready to write a chunk of data,
   // either any file header or a SingleBlock.
   using WriteDataCB = base::Callback<void(base::StringPiece)>;
 
-  explicit WebmMuxer(const WriteDataCB& write_data_callback);
+   WebmMuxer(bool use_vp9, const WriteDataCB& write_data_callback);

[miu, 2015/10/07 18:16:35]

Please add a comment that VP8 will be used if |use_vp9| is false.

Alternatively, consider using a "const char* codec_id" argument instead, where
|codec_id| must match one of the constants in mkvmuxer.hpp
(https://code.google.com/p/chromium/codesearch#chromium/src/third_party/libweb...).

[mcasas, 2015/10/07 21:01:15]

Done.
Wouldn't that surface implementation details? IOW the owner/ctor of this
class will have to know a detail of how libwebm identifies codecs.

[miu, 2015/10/07 21:56:56]

Yeah, that's a good point.  I suppose I'm fine with leaving it the way it is.

   ~WebmMuxer() override;
 
   // Adds a |video_frame| with |encoded_data.data()| to WebM Segment.
   void OnEncodedVideo(const scoped_refptr<VideoFrame>& video_frame,
                       scoped_ptr<std::string> encoded_data,
                       base::TimeTicks timestamp,
                       bool is_key_frame);
 
  private:
   friend class WebmMuxerTest;
 
   // Creates and adds a new video track. Called upon receiving the first
   // frame of a given Track, adds |frame_size| and |frame_rate| to the Segment
   // info, although individual frames passed to OnEncodedVideo() can have any
   // frame size.
   void AddVideoTrack(const gfx::Size& frame_size, double frame_rate);
 
   // IMkvWriter interface.
   mkvmuxer::int32 Write(const void* buf, mkvmuxer::uint32 len) override;
   mkvmuxer::int64 Position() const override;
   mkvmuxer::int32 Position(mkvmuxer::int64 position) override;
   bool Seekable() const override;
   void ElementStartNotify(mkvmuxer::uint64 element_id,
                           mkvmuxer::int64 position) override;
 
   // Used to DCHECK that we are called on the correct thread.
   base::ThreadChecker thread_checker_;
 
+  const bool use_vp9_;

[miu, 2015/10/07 18:16:35]

ditto: comment that meaning of "false" means VP8

[mcasas, 2015/10/07 21:01:14]

Done.

+
   // A caller-side identifier to interact with |segment_|, initialised upon
   // first frame arrival by AddVideoTrack().
   uint64_t track_index_;
 
   // Origin of times for frame timestamps.
   base::TimeTicks first_frame_timestamp_;
 
   // Callback to dump written data as being called by libwebm.
   const WriteDataCB write_data_callback_;
 
   // Rolling counter of the position in bytes of the written goo.
   base::CheckedNumeric<mkvmuxer::int64> position_;
 
   // The MkvMuxer active element.
   mkvmuxer::Segment segment_;
 
   DISALLOW_COPY_AND_ASSIGN(WebmMuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_LIBWEBM_MUXER_H_