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 media::VideoCaptureFormat& format,
  54       const base::TimeTicks& estimated_capture_time);
  55
  56   const scoped_refptr<base::MessageLoopProxy>& io_message_loop() {
  57     DCHECK(thread_checker_.CalledOnValidThread());
  58     return io_message_loop_;
  59   }
  60
  61   // Start monitor that frames are delivered to this object. I.E, that
  62   // |DeliverFrameOnIO| is called with a frame rate of |source_frame_rate|.
  63   // |on_muted_callback| is triggered on the main render thread.
  64   void StartFrameMonitoring(double source_frame_rate,
  65                             const OnMutedCallback& on_muted_callback);
  66   void StopFrameMonitoring();
  67
  68  private:
  69   virtual ~VideoTrackAdapter();
  70   friend class base::RefCountedThreadSafe<VideoTrackAdapter>;
  71
  72   void AddTrackOnIO(
  73       const MediaStreamVideoTrack* track,
  74       VideoCaptureDeliverFrameCB frame_callback,
  75       const gfx::Size& max_frame_size,
  76       double min_aspect_ratio,
  77       double max_aspect_ratio,
  78       double max_frame_rate);
  79   void RemoveTrackOnIO(const MediaStreamVideoTrack* track);
  80
  81   void StartFrameMonitoringOnIO(
  82     const OnMutedCallback& on_muted_state_callback,
  83     double source_frame_rate);
  84   void StopFrameMonitoringOnIO();
  85
  86   // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
  87   // inform of the situation (muted, not muted) via |set_muted_state_callback|.
  88   void CheckFramesReceivedOnIO(const OnMutedCallback& set_muted_state_callback,
  89                                uint64 old_frame_counter_snapshot);
  90
  91   // |thread_checker_| is bound to the main render thread.
  92   base::ThreadChecker thread_checker_;
  93
  94   scoped_refptr<base::MessageLoopProxy> io_message_loop_;
  95
  96   // |renderer_task_runner_| is used to ensure that
  97   // VideoCaptureDeliverFrameCB is released on the main render thread.
  98   scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
  99
 100   // VideoFrameResolutionAdapter is an inner class that is created on the main
 101   // render thread but operates on the IO-thread. It does the resolution
 102   // adaptation and delivers frames to all registered tracks on the IO-thread.
 103   class VideoFrameResolutionAdapter;
 104   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
 105       FrameAdapters;
 106   FrameAdapters adapters_;
 107
 108   // Set to true if frame monitoring has been started. It is only accessed on
 109   // the IO-thread.
 110   bool monitoring_frame_rate_;
 111
 112   // Keeps track of it frames have been received. It is only accessed on the
 113   // IO-thread.
 114   bool muted_state_;
 115
 116   // Running frame counter, accessed on the IO-thread.
 117   uint64 frame_counter_;
 118
 119   // Frame rate configured on the video source, accessed on the IO-thread.
 120   float source_frame_rate_;
 121
 122   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 123 };
 124
 125 }  // namespace content
 126
 127 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_