content/renderer/media/video_track_adapter.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_
   6 #define CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_
   7
   8 #include <vector>
   9
  10 #include "base/macros.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/time/time.h"
  13 #include "content/renderer/media/media_stream_video_track.h"
  14 #include "media/base/video_frame.h"
  15
  16 namespace content {
  17
  18 // VideoTrackAdapter is a helper class used by MediaStreamVideoSource used for
  19 // adapting the video resolution from a source implementation to the resolution
  20 // a track requires. Different tracks can have different resolution constraints.
  21 // The constraints can be set as max width and height as well as max and min
  22 // aspect ratio.
  23 // Video frames are delivered to a track using a VideoCaptureDeliverFrameCB on
  24 // the IO-thread.
  25 // Adaptations is done by wrapping the original media::VideoFrame in a new
  26 // media::VideoFrame with a new visible_rect and natural_size.
  27 class VideoTrackAdapter
  28     : public base::RefCountedThreadSafe<VideoTrackAdapter> {
  29  public:
  30   typedef base::Callback<void(bool mute_state)> OnMutedCallback;
  31
  32   explicit VideoTrackAdapter(
  33       const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
  34
  35   // Register |track| to receive video frames in |frame_callback| with
  36   // a resolution within the boundaries of the arguments.
  37   // Must be called on the main render thread. |frame_callback| is guaranteed to
  38   // be released on the main render thread.
  39   // |source_frame_rate| is used to calculate a prudent interval to check for
  40   // passing frames and inform of the result via |on_muted_state_callback|.
  41   void AddTrack(const MediaStreamVideoTrack* track,
  42                 VideoCaptureDeliverFrameCB frame_callback,
  43                 int max_width, int max_height,
  44                 double min_aspect_ratio,
  45                 double max_aspect_ratio,
  46                 double max_frame_rate);
  47   void RemoveTrack(const MediaStreamVideoTrack* track);
  48
  49   // Delivers |frame| to all tracks that have registered a callback.
  50   // Must be called on the IO-thread.
  51   void DeliverFrameOnIO(
  52       const scoped_refptr<media::VideoFrame>& frame,
  53       const base::TimeTicks& estimated_capture_time);
  54
  55   const scoped_refptr<base::MessageLoopProxy>& io_message_loop() {
  56     DCHECK(thread_checker_.CalledOnValidThread());
  57     return io_message_loop_;
  58   }
  59
  60   // Start monitor that frames are delivered to this object. I.E, that
  61   // |DeliverFrameOnIO| is called with a frame rate of |source_frame_rate|.
  62   // |on_muted_callback| is triggered on the main render thread.
  63   void StartFrameMonitoring(double source_frame_rate,
  64                             const OnMutedCallback& on_muted_callback);
  65   void StopFrameMonitoring();
  66
  67  private:
  68   virtual ~VideoTrackAdapter();
  69   friend class base::RefCountedThreadSafe<VideoTrackAdapter>;
  70
  71   void AddTrackOnIO(
  72       const MediaStreamVideoTrack* track,
  73       VideoCaptureDeliverFrameCB frame_callback,
  74       const gfx::Size& max_frame_size,
  75       double min_aspect_ratio,
  76       double max_aspect_ratio,
  77       double max_frame_rate);
  78   void RemoveTrackOnIO(const MediaStreamVideoTrack* track);
  79
  80   void StartFrameMonitoringOnIO(
  81     const OnMutedCallback& on_muted_state_callback,
  82     double source_frame_rate);
  83   void StopFrameMonitoringOnIO();
  84
  85   // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
  86   // inform of the situation (muted, not muted) via |set_muted_state_callback|.
  87   void CheckFramesReceivedOnIO(const OnMutedCallback& set_muted_state_callback,
  88                                uint64 old_frame_counter_snapshot);
  89
  90   // |thread_checker_| is bound to the main render thread.
  91   base::ThreadChecker thread_checker_;
  92
  93   const scoped_refptr<base::MessageLoopProxy> io_message_loop_;
  94
  95   // |renderer_task_runner_| is used to ensure that
  96   // VideoCaptureDeliverFrameCB is released on the main render thread.
  97   const scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
  98
  99   // VideoFrameResolutionAdapter is an inner class that is created on the main
 100   // render thread but operates on the IO-thread. It does the resolution
 101   // adaptation and delivers frames to all registered tracks on the IO-thread.
 102   class VideoFrameResolutionAdapter;
 103   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
 104       FrameAdapters;
 105   FrameAdapters adapters_;
 106
 107   // Set to true if frame monitoring has been started. It is only accessed on
 108   // the IO-thread.
 109   bool monitoring_frame_rate_;
 110
 111   // Keeps track of it frames have been received. It is only accessed on the
 112   // IO-thread.
 113   bool muted_state_;
 114
 115   // Running frame counter, accessed on the IO-thread.
 116   uint64 frame_counter_;
 117
 118   // Frame rate configured on the video source, accessed on the IO-thread.
 119   float source_frame_rate_;
 120
 121   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 122 };
 123
 124 }  // namespace content
 125
 126 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_