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 15 namespace media { 16 class VideoCaptureFormat; 17 class VideoFrame; 18 } 19 20 namespace blink { 21 class WebMediaStreamTrack; 22 } 23 24 namespace 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. 37 typedef 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. 47 class 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