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 MEDIA_FILTERS_VIDEO_FRAME_SCHEDULER_H_ 6#define MEDIA_FILTERS_VIDEO_FRAME_SCHEDULER_H_ 7 8#include "base/callback.h" 9#include "base/memory/ref_counted.h" 10#include "base/time/time.h" 11#include "media/base/media_export.h" 12 13namespace media { 14 15class VideoFrame; 16 17// Defines an abstract video frame scheduler that is capable of managing the 18// display of video frames at explicit times. 19class MEDIA_EXPORT VideoFrameScheduler { 20 public: 21 VideoFrameScheduler() {} 22 virtual ~VideoFrameScheduler() {} 23 24 enum Reason { 25 DISPLAYED, // Frame was displayed. 26 DROPPED, // Frame was dropped. 27 }; 28 typedef base::Callback<void(const scoped_refptr<VideoFrame>&, Reason)> DoneCB; 29 30 // Schedule |frame| to be displayed at |wall_ticks|, firing |done_cb| when 31 // the scheduler has finished with the frame. 32 // 33 // To avoid reentrancy issues, |done_cb| is run on a separate calling stack. 34 virtual void ScheduleVideoFrame(const scoped_refptr<VideoFrame>& frame, 35 base::TimeTicks wall_ticks, 36 const DoneCB& done_cb) = 0; 37 38 // Causes the scheduler to cancel any previously scheduled frames. 39 // 40 // There is no guarantee that |done_cb|'s for previously scheduled frames 41 // will not be run. Clients should implement callback tracking/cancellation 42 // if they are sensitive to old callbacks being run. 43 virtual void Reset() = 0; 44}; 45 46} // namespace media 47 48#endif // MEDIA_FILTERS_VIDEO_FRAME_SCHEDULER_H_ 49