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 "content/renderer/media/media_stream_video_track.h"
  13 #include "media/base/video_frame.h"
  14
  15 namespace content {
  16
  17 // VideoTrackAdapter is a helper class used by MediaStreamVideoSource used for
  18 // adapting the video resolution from a source implementation to the resolution
  19 // a track requires. Different tracks can have different resolution constraints.
  20 // The constraints can be set as max width and height as well as max and min
  21 // aspect ratio.
  22 // Video frames are delivered to a track using a VideoCaptureDeliverFrameCB on
  23 // the IO-thread.
  24 // Adaptations is done by wrapping the original media::VideoFrame in a new
  25 // media::VideoFrame with a new visible_rect and natural_size.
  26 class VideoTrackAdapter
  27     : public base::RefCountedThreadSafe<VideoTrackAdapter> {
  28  public:
  29   explicit VideoTrackAdapter(
  30       const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
  31
  32   // Register |track| to receive video frames in |frame_callback| with
  33   // a resolution within the boundaries of the arguments.
  34   // Must be called on the main render thread. |frame_callback| is guaranteed to
  35   // be released on the main render thread.
  36   void AddTrack(const MediaStreamVideoTrack* track,
  37                 VideoCaptureDeliverFrameCB frame_callback,
  38                 int max_width, int max_height,
  39                 double min_aspect_ratio,
  40                 double max_aspect_ratio);
  41   void RemoveTrack(const MediaStreamVideoTrack* track);
  42
  43   // Delivers |frame| to all tracks that have registered a callback.
  44   // Must be called on the IO-thread.
  45   void DeliverFrameOnIO(
  46       const scoped_refptr<media::VideoFrame>& frame,
  47       const media::VideoCaptureFormat& format);
  48
  49   const scoped_refptr<base::MessageLoopProxy>& io_message_loop() {
  50     DCHECK(thread_checker_.CalledOnValidThread());
  51     return io_message_loop_;
  52   }
  53
  54  private:
  55   virtual ~VideoTrackAdapter();
  56   friend class base::RefCountedThreadSafe<VideoTrackAdapter>;
  57
  58   void AddTrackOnIO(
  59       const MediaStreamVideoTrack* track,
  60       VideoCaptureDeliverFrameCB frame_callback,
  61       int max_width, int max_height,
  62       double min_aspect_ratio,
  63       double max_aspect_ratio);
  64   void RemoveTrackOnIO(const MediaStreamVideoTrack* track);
  65
  66   // |thread_checker_| is bound to the main render thread.
  67   base::ThreadChecker thread_checker_;
  68
  69   scoped_refptr<base::MessageLoopProxy> io_message_loop_;
  70
  71   // |renderer_task_runner_| is used to ensure that
  72   // VideoCaptureDeliverFrameCB is released on the main render thread.
  73   scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
  74
  75   // VideoFrameResolutionAdapter is an inner class that is created on the main
  76   // render thread but operates on the IO-thread. It does the resolution
  77   // adaptation and delivers frames to all registered tracks on the IO-thread.
  78   class VideoFrameResolutionAdapter;
  79   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
  80       FrameAdapters;
  81   FrameAdapters adapters_;
  82
  83   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
  84 };
  85
  86 }  // namespace content
  87
  88 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_