1 /* 2 * Copyright 2014, The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef VIDEO_FRAME_SCHEDULER_H_ 18 #define VIDEO_FRAME_SCHEDULER_H_ 19 20 #include <utils/RefBase.h> 21 #include <utils/Timers.h> 22 23 #include <media/stagefright/foundation/ABase.h> 24 25 namespace android { 26 27 struct ISurfaceComposer; 28 29 struct VideoFrameScheduler : public RefBase { 30 VideoFrameScheduler(); 31 32 // (re)initialize scheduler 33 void init(float videoFps = -1); 34 // use in case of video render-time discontinuity, e.g. seek 35 void restart(); 36 // get adjusted nanotime for a video frame render at renderTime 37 nsecs_t schedule(nsecs_t renderTime); 38 39 // returns the vsync period for the main display 40 nsecs_t getVsyncPeriod(); 41 42 void release(); 43 44 static const size_t kHistorySize = 8; 45 46 protected: 47 virtual ~VideoFrameScheduler(); 48 49 private: 50 struct PLL { 51 PLL(); 52 53 // reset PLL to new PLL 54 void reset(float fps = -1); 55 // keep current estimate, but restart phase 56 void restart(); 57 // returns period 58 nsecs_t addSample(nsecs_t time); 59 60 private: 61 nsecs_t mPeriod; 62 nsecs_t mPhase; 63 64 bool mPrimed; // have an estimate for the period 65 size_t mSamplesUsedForPriming; 66 67 nsecs_t mLastTime; // last input time 68 nsecs_t mRefitAt; // next input time to fit at 69 70 size_t mNumSamples; // can go past kHistorySize 71 nsecs_t mTimes[kHistorySize]; 72 73 void test(); 74 // returns whether fit was successful 75 bool fit(nsecs_t phase, nsecs_t period, size_t numSamples, 76 int64_t *a, int64_t *b, int64_t *err); 77 void prime(size_t numSamples); 78 }; 79 80 void updateVsync(); 81 82 nsecs_t mVsyncTime; // vsync timing from display 83 nsecs_t mVsyncPeriod; 84 nsecs_t mVsyncRefreshAt; // next time to refresh timing info 85 86 nsecs_t mLastVsyncTime; // estimated vsync time for last frame 87 nsecs_t mTimeCorrection; // running adjustment 88 89 PLL mPll; // PLL for video frame rate based on render time 90 91 sp<ISurfaceComposer> mComposer; 92 93 DISALLOW_EVIL_CONSTRUCTORS(VideoFrameScheduler); 94 }; 95 96 } // namespace android 97 98 #endif // VIDEO_FRAME_SCHEDULER_H_ 99 100