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