1// Copyright 2013 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_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
6#define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
7
8#include "base/callback.h"
9#include "base/compiler_specific.h"
10#include "base/memory/ref_counted.h"
11#include "base/time/time.h"
12#include "content/common/content_export.h"
13#include "content/public/renderer/media_stream_sink.h"
14
15namespace media {
16class VideoCaptureFormat;
17class VideoFrame;
18}
19
20namespace blink {
21class WebMediaStreamTrack;
22}
23
24namespace content {
25
26// This callback is used to deliver video frames.
27// |estimated_capture_time| - An optional field to provide the capture time of
28// the delivered video frame. This field usually means the local time when the
29// video frame was generated. It is possible for this value to be null if this
30// timing information cannot be determined. There is no gurantee that this
31// value is accurate. For example video frames from a remote source can only
32// provide this timing information as an estimate.
33// |video_frame->timestamp()| gives the presentation timestamp of the video
34// frame relative to the first frame generated by the corresponding source.
35// Because a source can start generating frames before a subscriber is added,
36// the first video frame delivered may not have timestamp equal to 0.
37typedef base::Callback<
38  void(const scoped_refptr<media::VideoFrame>& video_frame,
39       const media::VideoCaptureFormat& format,
40       const base::TimeTicks& estimated_capture_time)>
41    VideoCaptureDeliverFrameCB;
42
43// MediaStreamVideoSink is an interface used for receiving video frames from a
44// Video Stream Track or a Video Source.
45// http://dev.w3.org/2011/webrtc/editor/getusermedia.html
46// All methods calls will be done from the main render thread.
47class CONTENT_EXPORT MediaStreamVideoSink : public MediaStreamSink {
48 public:
49  // An implementation of MediaStreamVideoSink should call AddToVideoTrack when
50  // it is ready to receive data from a video track. Before the implementation
51  // is destroyed, RemoveFromVideoTrack must be called.
52  //
53  // Calls to these methods must be done on the main render thread.
54  // Note that |callback| for frame delivery happens on the IO thread.
55  //
56  // Calling RemoveFromVideoTrack also not stop frame delivery through the
57  // callback immediately because it may happen on another thread.
58  // The added callback will be reset on the render thread.
59  static void AddToVideoTrack(MediaStreamVideoSink* sink,
60                              const VideoCaptureDeliverFrameCB& callback,
61                              const blink::WebMediaStreamTrack& track);
62  static void RemoveFromVideoTrack(MediaStreamVideoSink* sink,
63                                   const blink::WebMediaStreamTrack& track);
64
65 protected:
66  virtual ~MediaStreamVideoSink() {}
67};
68
69
70}  // namespace content
71
72#endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
73