1 /* 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MEDIA_BASE_VIDEO_BROADCASTER_H_ 12 #define MEDIA_BASE_VIDEO_BROADCASTER_H_ 13 14 #include "api/media_stream_interface.h" 15 #include "api/scoped_refptr.h" 16 #include "api/sequence_checker.h" 17 #include "api/video/video_frame_buffer.h" 18 #include "api/video/video_source_interface.h" 19 #include "media/base/video_source_base.h" 20 #include "rtc_base/synchronization/mutex.h" 21 #include "rtc_base/thread_annotations.h" 22 23 namespace rtc { 24 25 // VideoBroadcaster broadcast video frames to sinks and combines VideoSinkWants 26 // from its sinks. It does that by implementing rtc::VideoSourceInterface and 27 // rtc::VideoSinkInterface. The class is threadsafe; methods may be called on 28 // any thread. This is needed because VideoStreamEncoder calls AddOrUpdateSink 29 // both on the worker thread and on the encoder task queue. 30 class VideoBroadcaster : public VideoSourceBase, 31 public VideoSinkInterface<webrtc::VideoFrame> { 32 public: 33 VideoBroadcaster(); 34 ~VideoBroadcaster() override; 35 36 // Adds a new, or updates an already existing sink. If the sink is new and 37 // ProcessConstraints has been called previously, the new sink's 38 // OnConstraintsCalled method will be invoked with the most recent 39 // constraints. 40 void AddOrUpdateSink(VideoSinkInterface<webrtc::VideoFrame>* sink, 41 const VideoSinkWants& wants) override; 42 void RemoveSink(VideoSinkInterface<webrtc::VideoFrame>* sink) override; 43 44 // Returns true if the next frame will be delivered to at least one sink. 45 bool frame_wanted() const; 46 47 // Returns VideoSinkWants a source is requested to fulfill. They are 48 // aggregated by all VideoSinkWants from all sinks. 49 VideoSinkWants wants() const; 50 51 // This method ensures that if a sink sets rotation_applied == true, 52 // it will never receive a frame with pending rotation. Our caller 53 // may pass in frames without precise synchronization with changes 54 // to the VideoSinkWants. 55 void OnFrame(const webrtc::VideoFrame& frame) override; 56 57 void OnDiscardedFrame() override; 58 59 // Called on the network thread when constraints change. Forwards the 60 // constraints to sinks added with AddOrUpdateSink via OnConstraintsChanged. 61 void ProcessConstraints( 62 const webrtc::VideoTrackSourceConstraints& constraints); 63 64 protected: 65 void UpdateWants() RTC_EXCLUSIVE_LOCKS_REQUIRED(sinks_and_wants_lock_); 66 const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& GetBlackFrameBuffer( 67 int width, 68 int height) RTC_EXCLUSIVE_LOCKS_REQUIRED(sinks_and_wants_lock_); 69 70 mutable webrtc::Mutex sinks_and_wants_lock_; 71 72 VideoSinkWants current_wants_ RTC_GUARDED_BY(sinks_and_wants_lock_); 73 rtc::scoped_refptr<webrtc::VideoFrameBuffer> black_frame_buffer_; 74 bool previous_frame_sent_to_all_sinks_ RTC_GUARDED_BY(sinks_and_wants_lock_) = 75 true; 76 absl::optional<webrtc::VideoTrackSourceConstraints> last_constraints_ 77 RTC_GUARDED_BY(sinks_and_wants_lock_); 78 }; 79 80 } // namespace rtc 81 82 #endif // MEDIA_BASE_VIDEO_BROADCASTER_H_ 83