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/*
* Copyright 2015 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MEDIA_BASE_SHELL_VIDEO_FRAME_PROVIDER_H_
#define MEDIA_BASE_SHELL_VIDEO_FRAME_PROVIDER_H_
#include <vector>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/lock.h"
#include "base/time.h"
#include "media/base/video_frame.h"
namespace media {
// TODO: Remove Shell prefix.
// The ShellVideoFrameProvider manages the backlog for video frames. It has the
// following functionalities:
// 1. It caches the video frames ready to be displayed.
// 2. It decides which frame to be displayed at the current time.
// 3. It removes frames that will no longer be displayed.
class ShellVideoFrameProvider
: public base::RefCountedThreadSafe<ShellVideoFrameProvider> {
public:
explicit ShellVideoFrameProvider(scoped_refptr<VideoFrame> punch_out = NULL);
// The calling back returns the current media time and a bool which is set to
// true when a seek is in progress.
typedef base::Callback<void(base::TimeDelta*, bool*)>
MediaTimeAndSeekingStateCB;
// This class uses the media time to decide which frame is current. It
// retrieves the media time from the registered media_time_cb. There can only
// be one registered media_time_cb at a certain time, a call to
// RegisterMediaTimeAndSeekingStateCB() will overwrite the previously
// registered callback.
void RegisterMediaTimeAndSeekingStateCB(
const MediaTimeAndSeekingStateCB& media_time_and_seeking_state_cb);
// This function unregisters the media time callback if it hasn't been
// overwritten by another callback.
void UnregisterMediaTimeAndSeekingStateCB(
const MediaTimeAndSeekingStateCB& media_time_and_seeking_state_cb);
// Returns the current frame to be displayed if there is one. Otherwise it
// returns NULL.
const scoped_refptr<VideoFrame>& GetCurrentFrame();
void AddFrame(const scoped_refptr<VideoFrame>& frame);
// Flush will clear all cached frames except the current frame. So the current
// frame can still be displayed during seek.
void Flush();
// Stop will clear all cached frames including the current frame.
void Stop();
size_t GetNumOfFramesCached() const;
// Return true if VideoFrames have been released from the internal frames_
// queue since the last time this was called.
bool QueryAndResetHasConsumedFrames();
// Return the value of |dropped_frames_| and reset it to 0.
int ResetAndReturnDroppedFrames();
private:
void GetMediaTimeAndSeekingState_Locked(base::TimeDelta* media_time,
bool* is_seeking) const;
scoped_refptr<VideoFrame> punch_out_;
mutable base::Lock frames_lock_;
MediaTimeAndSeekingStateCB media_time_and_seeking_state_cb_;
std::vector<scoped_refptr<VideoFrame> > frames_;
scoped_refptr<VideoFrame> current_frame_;
bool has_consumed_frames_;
int dropped_frames_;
#if !defined(__LB_SHELL__FOR_RELEASE__)
int max_delay_in_microseconds_;
#endif // !defined(__LB_SHELL__FOR_RELEASE__)
DISALLOW_COPY_AND_ASSIGN(ShellVideoFrameProvider);
};
} // namespace media
#endif // MEDIA_BASE_SHELL_VIDEO_FRAME_PROVIDER_H_