am b7208196: Use audio clock as the reference media clock (4fc2c928) · Commits · e / os / android_frameworks_base

include/media/stagefright/MPEG4Writer.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -128,6 +128,12 @@ private:
		// Write the first chunk from the given ChunkInfo.
		void writeFirstChunk(ChunkInfo* info);

		// Adjust other track media clock (presumably wall clock)
		// based on audio track media clock with the drift time.
		int64_t mDriftTimeUs;
		void addDriftTimeUs(int64_t driftTimeUs);
		int64_t getDriftTimeUs();

		void lock();
		void unlock();

include/media/stagefright/MetaData.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -86,10 +86,10 @@ enum {

		// Track authoring progress status
		// kKeyTrackTimeStatus is used to track progress in elapsed time
		// kKeyTrackFrameStatus is used to track progress in authored frames
		kKeyTrackFrameStatus = 'tkfm', // int32_t
		kKeyTrackTimeStatus = 'tktm', // int64_t

		kKeyNotRealTime = 'ntrt', // bool (int32_t)

		};

		enum {

media/libstagefright/MPEG4Writer.cpp

+65 −0

Original line number	Diff line number	Diff line
		@@ -72,6 +72,11 @@ private:
		bool mIsAudio;
		bool mIsMPEG4;
		int64_t mTrackDurationUs;

		// For realtime applications, we need to adjust the media clock
		// for video track based on the audio media clock
		bool mIsRealTimeRecording;
		int64_t mMaxTimeStampUs;
		int64_t mEstimatedTrackSizeBytes;
		int64_t mMaxWriteTimeUs;
		int32_t mTimeScale;
		@@ -940,6 +945,7 @@ status_t MPEG4Writer::startWriterThread() {

		mDone = false;
		mIsFirstChunk = true;
		mDriftTimeUs = 0;
		for (List<Track *>::iterator it = mTracks.begin();
		it != mTracks.end(); ++it) {
		ChunkInfo info;
		@@ -967,6 +973,14 @@ status_t MPEG4Writer::Track::start(MetaData *params) {
		startTimeUs = 0;
		}

		mIsRealTimeRecording = true;
		{
		int32_t isNotRealTime;
		if (params && params->findInt32(kKeyNotRealTime, &isNotRealTime)) {
		mIsRealTimeRecording = (isNotRealTime == 0);
		}
		}

		initTrackingProgressStatus(params);

		sp<MetaData> meta = new MetaData;
		@@ -1326,6 +1340,10 @@ void MPEG4Writer::Track::threadEntry() {
		uint32_t previousSampleSize = 0; // Size of the previous sample
		int64_t previousPausedDurationUs = 0;
		int64_t timestampUs;

		int64_t wallClockTimeUs = 0;
		int64_t lastWallClockTimeUs = 0;

		sp<MetaData> meta_data;
		bool collectStats = collectStatisticalData();

		@@ -1429,6 +1447,33 @@ void MPEG4Writer::Track::threadEntry() {
		}

		timestampUs -= previousPausedDurationUs;
		if (mIsRealTimeRecording && !mIsAudio) {
		// The minor adjustment on the timestamp is heuristic/experimental
		// We are adjusting the timestamp to reduce the fluctuation of the duration
		// of neighboring samples. This in turn helps reduce the track header size,
		// especially, the number of entries in the "stts" box.
		if (mNumSamples > 1) {
		int64_t durationUs = timestampUs + mOwner->getDriftTimeUs() - lastTimestampUs;
		int64_t diffUs = (durationUs > lastDurationUs)
		? durationUs - lastDurationUs
		: lastDurationUs - durationUs;
		if (diffUs <= 5000) { // XXX: Magic number 5ms
		timestampUs = lastTimestampUs + lastDurationUs;
		} else {
		timestampUs += mOwner->getDriftTimeUs();
		}
		}
		}
		CHECK(timestampUs >= 0);
		if (mNumSamples > 1) {
		if (timestampUs <= lastTimestampUs) {
		LOGW("Drop a frame, since it arrives too late!");
		copy->release();
		copy = NULL;
		continue;
		}
		}

		LOGV("time stamp: %lld and previous paused duration %lld",
		timestampUs, previousPausedDurationUs);
		if (timestampUs > mTrackDurationUs) {
		@@ -1454,6 +1499,14 @@ void MPEG4Writer::Track::threadEntry() {
		}
		lastDurationUs = timestampUs - lastTimestampUs;
		lastTimestampUs = timestampUs;
		if (mIsRealTimeRecording && mIsAudio) {
		wallClockTimeUs = systemTime() / 1000;
		int64_t wallClockDurationUs = wallClockTimeUs - lastWallClockTimeUs;
		if (mNumSamples > 2) {
		mOwner->addDriftTimeUs(lastDurationUs - wallClockDurationUs);
		}
		lastWallClockTimeUs = wallClockTimeUs;
		}

		if (isSync != 0) {
		mStssTableEntries.push_back(mNumSamples);
		@@ -1679,6 +1732,18 @@ void MPEG4Writer::Track::logStatisticalData(bool isAudio) {
		}
		}

		void MPEG4Writer::addDriftTimeUs(int64_t driftTimeUs) {
		LOGV("addDriftTimeUs: %lld us", driftTimeUs);
		Mutex::Autolock autolock(mLock);
		mDriftTimeUs += driftTimeUs;
		}

		int64_t MPEG4Writer::getDriftTimeUs() {
		LOGV("getDriftTimeUs: %lld us", mDriftTimeUs);
		Mutex::Autolock autolock(mLock);
		return mDriftTimeUs;
		}

		void MPEG4Writer::Track::bufferChunk(int64_t timestampUs) {
		LOGV("bufferChunk");