1 files changed, 103 insertions, 0 deletions
diff --git a/include/media/stagefright/VideoFrameScheduler.h b/include/media/stagefright/VideoFrameScheduler.h
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+++ b/include/media/stagefright/VideoFrameScheduler.h
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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 {
+
+class 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();
+
+    // returns the current frames-per-second, or 0.f if not primed
+    float getFrameRate();
+
+    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 or 0 if not yet primed
+        nsecs_t addSample(nsecs_t time);
+        nsecs_t getPeriod() const;
+
+    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_
+