Support alpha channel recording for VPX in MediaRecorder

media/muxers/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_MUXERS_WEBM_MUXER_H_
 #define MEDIA_MUXERS_WEBM_MUXER_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 49 matching lines @@
   // |codec| can be VP8 or VP9 and should coincide with whatever is sent in
   // OnEncodedVideo().
   WebmMuxer(VideoCodec codec,
             bool has_video_,
             bool has_audio_,
             const WriteDataCB& write_data_callback);
   ~WebmMuxer() override;
 
   // Functions to add video and audio frames with |encoded_data.data()|
   // to WebM Segment. Either one returns true on success.
+  // |encoded_alpha| represents the encode output of alpha channel when
+  // available, can be nullptr otherwise.
   bool OnEncodedVideo(const VideoParameters& params,
                       std::unique_ptr<std::string> encoded_data,
+                      std::unique_ptr<std::string> encoded_alpha,
                       base::TimeTicks timestamp,
                       bool is_key_frame);
   bool OnEncodedAudio(const media::AudioParameters& params,
                       std::unique_ptr<std::string> encoded_data,
                       base::TimeTicks timestamp);
 
   void Pause();
   void Resume();
 
   void ForceOneLibWebmErrorForTesting() { force_one_libwebm_error_ = true; }
@@ skipping 12 matching lines @@
   // 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;
 
   // Helper to simplify saving frames. Returns true on success.
   bool AddFrame(std::unique_ptr<std::string> encoded_data,
+                std::unique_ptr<std::string> encoded_alpha_data,
                 uint8_t track_index,
                 base::TimeDelta timestamp,
                 bool is_key_frame);
 
   // Used to DCHECK that we are called on the correct thread.
   base::ThreadChecker thread_checker_;
 
   // Video Codec configured on construction.
   const VideoCodec video_codec_;
 
@@ skipping 24 matching lines @@
 
   // The MkvMuxer active element.
   mkvmuxer::Segment segment_;
   // Flag to force the next call to a |segment_| method to return false.
   bool force_one_libwebm_error_;
 
   // Hold on to all encoded video frames to dump them with and when audio is
   // received, if expected, since WebM headers can only be written once.
   struct EncodedVideoFrame {
     EncodedVideoFrame(std::unique_ptr<std::string> data,
+                      std::unique_ptr<std::string> alpha_data,
                       base::TimeTicks timestamp,
                       bool is_keyframe);
     ~EncodedVideoFrame();
 
     std::unique_ptr<std::string> data;
+    std::unique_ptr<std::string> alpha_data;
     base::TimeTicks timestamp;
     bool is_keyframe;
 
    private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(EncodedVideoFrame);
   };
   std::deque<std::unique_ptr<EncodedVideoFrame>> encoded_frames_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(WebmMuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MUXERS_WEBM_MUXER_H_