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       scoped_refptr<base::SingleThreadTaskRunner> io_task_runner);
  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(const scoped_refptr<media::VideoFrame>& frame,
  52                         base::TimeTicks estimated_capture_time);
  53
  54   base::SingleThreadTaskRunner* io_task_runner() const {
  55     DCHECK(thread_checker_.CalledOnValidThread());
  56     return io_task_runner_.get();
  57   }
  58
  59   // Start monitor that frames are delivered to this object. I.E, that
  60   // |DeliverFrameOnIO| is called with a frame rate of |source_frame_rate|.
  61   // |on_muted_callback| is triggered on the main render thread.
  62   void StartFrameMonitoring(double source_frame_rate,
  63                             const OnMutedCallback& on_muted_callback);
  64   void StopFrameMonitoring();
  65
  66  private:
  67   virtual ~VideoTrackAdapter();
  68   friend class base::RefCountedThreadSafe<VideoTrackAdapter>;
  69
  70   void AddTrackOnIO(
  71       const MediaStreamVideoTrack* track,
  72       VideoCaptureDeliverFrameCB frame_callback,
  73       const gfx::Size& max_frame_size,
  74       double min_aspect_ratio,
  75       double max_aspect_ratio,
  76       double max_frame_rate);
  77   void RemoveTrackOnIO(const MediaStreamVideoTrack* track);
  78
  79   void StartFrameMonitoringOnIO(
  80     const OnMutedCallback& on_muted_state_callback,
  81     double source_frame_rate);
  82   void StopFrameMonitoringOnIO();
  83
  84   // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
  85   // inform of the situation (muted, not muted) via |set_muted_state_callback|.
  86   void CheckFramesReceivedOnIO(const OnMutedCallback& set_muted_state_callback,
  87                                uint64 old_frame_counter_snapshot);
  88
  89   // |thread_checker_| is bound to the main render thread.
  90   base::ThreadChecker thread_checker_;
  91
  92   const scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
  93
  94   // |renderer_task_runner_| is used to ensure that
  95   // VideoCaptureDeliverFrameCB is released on the main render thread.
  96   const scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
  97
  98   // VideoFrameResolutionAdapter is an inner class that is created on the main
  99   // render thread but operates on the IO-thread. It does the resolution
 100   // adaptation and delivers frames to all registered tracks on the IO-thread.
 101   class VideoFrameResolutionAdapter;
 102   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
 103       FrameAdapters;
 104   FrameAdapters adapters_;
 105
 106   // Set to true if frame monitoring has been started. It is only accessed on
 107   // the IO-thread.
 108   bool monitoring_frame_rate_;
 109
 110   // Keeps track of it frames have been received. It is only accessed on the
 111   // IO-thread.
 112   bool muted_state_;
 113
 114   // Running frame counter, accessed on the IO-thread.
 115   uint64 frame_counter_;
 116
 117   // Frame rate configured on the video source, accessed on the IO-thread.
 118   float source_frame_rate_;
 119
 120   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 121 };
 122
 123 }  // namespace content
 124
 125 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_