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/*
* Copyright 2014, The Android Open Source Project
*
* 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 VIDEO_FRAME_SCHEDULER_H_
#define VIDEO_FRAME_SCHEDULER_H_
#include <utils/RefBase.h>
#include <utils/Timers.h>
#include <media/stagefright/foundation/ABase.h>
namespace android {
struct ISurfaceComposer;
struct VideoFrameScheduler : public RefBase {
VideoFrameScheduler();
// (re)initialize scheduler
void init(float videoFps = -1);
// use in case of video render-time discontinuity, e.g. seek
void restart();
// get adjusted nanotime for a video frame render at renderTime
nsecs_t schedule(nsecs_t renderTime);
// returns the vsync period for the main display
nsecs_t getVsyncPeriod();
void release();
static const size_t kHistorySize = 8;
protected:
virtual ~VideoFrameScheduler();
private:
struct PLL {
PLL();
// reset PLL to new PLL
void reset(float fps = -1);
// keep current estimate, but restart phase
void restart();
// returns period
nsecs_t addSample(nsecs_t time);
private:
nsecs_t mPeriod;
nsecs_t mPhase;
bool mPrimed; // have an estimate for the period
size_t mSamplesUsedForPriming;
nsecs_t mLastTime; // last input time
nsecs_t mRefitAt; // next input time to fit at
size_t mNumSamples; // can go past kHistorySize
nsecs_t mTimes[kHistorySize];
void test();
// returns whether fit was successful
bool fit(nsecs_t phase, nsecs_t period, size_t numSamples,
int64_t *a, int64_t *b, int64_t *err);
void prime(size_t numSamples);
};
void updateVsync();
nsecs_t mVsyncTime; // vsync timing from display
nsecs_t mVsyncPeriod;
nsecs_t mVsyncRefreshAt; // next time to refresh timing info
nsecs_t mLastVsyncTime; // estimated vsync time for last frame
nsecs_t mTimeCorrection; // running adjustment
PLL mPll; // PLL for video frame rate based on render time
sp<ISurfaceComposer> mComposer;
DISALLOW_EVIL_CONSTRUCTORS(VideoFrameScheduler);
};
} // namespace android
#endif // VIDEO_FRAME_SCHEDULER_H_
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