Home | History | Annotate | Download | only in media 
      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_
    128