Merge "AudioTrack: Fix timestamp jitter" into nyc-dev (7aa45dd7) · Commits · e / os / android_frameworks_av

include/media/AudioTimestamp.h

+10 −4

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ public:

		struct ExtendedTimestamp {
		enum Location {
		LOCATION_INVALID = -1,
		LOCATION_CLIENT, // timestamp of last read frame from client-server track buffer
		LOCATION_SERVER, // timestamp of newest frame from client-server track buffer
		LOCATION_KERNEL, // timestamp of newest frame in the kernel (alsa) buffer.
		@@ -89,8 +90,10 @@ struct ExtendedTimestamp {
		}

		// Returns the best timestamp as judged from the closest-to-hw stage in the
		// pipeline with a valid timestamp.
		status_t getBestTimestamp(int64_t position, int64_t time, int timebase) const {
		// pipeline with a valid timestamp. If the optional location parameter is non-null,
		// it will be filled with the location where the time was obtained.
		status_t getBestTimestamp(
		int64_t position, int64_t time, int timebase, Location *location = nullptr) const {
		if (position == nullptr \|\| time == nullptr
		\|\| timebase < 0 \|\| timebase >= TIMEBASE_MAX) {
		return BAD_VALUE;
		@@ -102,18 +105,21 @@ struct ExtendedTimestamp {
		if (mTimeNs[i] > 0) {
		*position = mPosition[i];
		*time = mTimeNs[i] + mTimebaseOffset[timebase];
		if (location != nullptr) {
		*location = (Location)i;
		}
		return OK;
		}
		}
		return INVALID_OPERATION;
		}

		status_t getBestTimestamp(AudioTimestamp *timestamp) const {
		status_t getBestTimestamp(AudioTimestamp timestamp, Location location = nullptr) const {
		if (timestamp == nullptr) {
		return BAD_VALUE;
		}
		int64_t position, time;
		if (getBestTimestamp(&position, &time, TIMEBASE_MONOTONIC) == OK) {
		if (getBestTimestamp(&position, &time, TIMEBASE_MONOTONIC, location) == OK) {
		timestamp->mPosition = position;
		timestamp->mTime.tv_sec = time / 1000000000;
		timestamp->mTime.tv_nsec = time - timestamp->mTime.tv_sec * 1000000000LL;

include/media/AudioTrack.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -1046,6 +1046,8 @@ protected:
		bool mTimestampStartupGlitchReported; // reduce log spam
		bool mRetrogradeMotionReported; // reduce log spam
		AudioTimestamp mPreviousTimestamp; // used to detect retrograde motion
		ExtendedTimestamp::Location mPreviousLocation; // location used for previous timestamp
		double mComputedLatencyMs; // latency between server and kernel

		uint32_t mUnderrunCountOffset; // updated when restoring tracks

media/libmedia/AudioTrack.cpp

+38 −1

Original line number	Diff line number	Diff line
		@@ -535,6 +535,8 @@ status_t AudioTrack::set(
		mPreviousTimestampValid = false;
		mTimestampStartupGlitchReported = false;
		mRetrogradeMotionReported = false;
		mPreviousLocation = ExtendedTimestamp::LOCATION_INVALID;
		mComputedLatencyMs = 0.;
		mUnderrunCountOffset = 0;
		mFramesWritten = 0;
		mFramesWrittenServerOffset = 0;
		@@ -567,6 +569,8 @@ status_t AudioTrack::start()
		mPreviousTimestampValid = false;
		mTimestampStartupGlitchReported = false;
		mRetrogradeMotionReported = false;
		mPreviousLocation = ExtendedTimestamp::LOCATION_INVALID;
		mComputedLatencyMs = 0.;

		// read last server side position change via timestamp.
		ExtendedTimestamp ets;
		@@ -2362,7 +2366,40 @@ status_t AudioTrack::getTimestamp(AudioTimestamp& timestamp)
		ExtendedTimestamp ets;
		status = mProxy->getTimestamp(&ets);
		if (status == OK) {
		status = ets.getBestTimestamp(&timestamp);
		ExtendedTimestamp::Location location;
		status = ets.getBestTimestamp(&timestamp, &location);

		if (status == OK) {
		// It is possible that the best location has moved from the kernel to the server.
		// In this case we adjust the position from the previous computed latency.
		if (location == ExtendedTimestamp::LOCATION_SERVER) {
		ALOGW_IF(mPreviousLocation == ExtendedTimestamp::LOCATION_KERNEL,
		"getTimestamp() location moved from kernel to server");
		const double latencyMs = mComputedLatencyMs > 0.
		? mComputedLatencyMs : mAfLatency;
		const int64_t frames =
		int64_t(latencyMs * mSampleRate * mPlaybackRate.mSpeed / 1000);
		ALOGV("mComputedLatencyMs:%lf mAfLatency:%u frame adjustment:%lld",
		mComputedLatencyMs, mAfLatency, (long long)frames);
		if (frames >= ets.mPosition[location]) {
		timestamp.mPosition = 0;
		} else {
		timestamp.mPosition = (uint32_t)(ets.mPosition[location] - frames);
		}
		} else if (location == ExtendedTimestamp::LOCATION_KERNEL) {
		const double bufferDiffMs =
		(double)(ets.mPosition[ExtendedTimestamp::LOCATION_SERVER]
		- ets.mPosition[ExtendedTimestamp::LOCATION_KERNEL])
		* 1000 / ((double)mSampleRate * mPlaybackRate.mSpeed);
		mComputedLatencyMs = bufferDiffMs > 0. ? bufferDiffMs : 0.;
		ALOGV("mComputedLatencyMs:%lf mAfLatency:%d",
		mComputedLatencyMs, mAfLatency);
		}
		mPreviousLocation = location;
		} else {
		// right after AudioTrack is started, one may not find a timestamp
		ALOGV("getBestTimestamp did not find timestamp");
		}
		}
		if (status == INVALID_OPERATION) {
		status = WOULD_BLOCK;