Fix loop and position restoration in static AudioTracks (4ede21d9) · Commits · e / os / android_frameworks_av

include/media/AudioTrack.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -732,13 +732,16 @@ protected:
		bool mRefreshRemaining; // processAudioBuffer() should refresh
		// mRemainingFrames and mRetryOnPartialBuffer

		// used for static track cbf and restoration
		int32_t mLoopCount; // last setLoop loopCount; zero means disabled
		uint32_t mLoopStart; // last setLoop loopStart
		uint32_t mLoopEnd; // last setLoop loopEnd

		// These are private to processAudioBuffer(), and are not protected by a lock
		uint32_t mRemainingFrames; // number of frames to request in obtainBuffer()
		bool mRetryOnPartialBuffer; // sleep and retry after partial obtainBuffer()
		uint32_t mObservedSequence; // last observed value of mSequence

		uint32_t mLoopPeriod; // in frames, zero means looping is disabled

		uint32_t mMarkerPosition; // in wrapping (overflow) frame units
		bool mMarkerReached;
		uint32_t mNewPosition; // in frames

include/private/media/AudioTrackShared.h

+29 −7

Original line number	Diff line number	Diff line
		@@ -85,13 +85,32 @@ struct StaticAudioTrackState {

		typedef SingleStateQueue<StaticAudioTrackState> StaticAudioTrackSingleStateQueue;

		struct StaticAudioTrackPosLoop {
		// Do not define constructors, destructors, or virtual methods as this is part of a
		// union in shared memory and will not get called properly.

		// These fields should both be size_t, but since they are located in shared memory we
		// force to 32-bit. The client and server may have different typedefs for size_t.

		// This struct information is stored in a single state queue to communicate the
		// static AudioTrack server state to the client while data is consumed.
		// It is smaller than StaticAudioTrackState to prevent unnecessary information from
		// being sent.

		uint32_t mBufferPosition;
		int32_t mLoopCount;
		};

		typedef SingleStateQueue<StaticAudioTrackPosLoop> StaticAudioTrackPosLoopQueue;

		struct AudioTrackSharedStatic {
		// client requests to the server for loop or position changes.
		StaticAudioTrackSingleStateQueue::Shared
		mSingleStateQueue;
		// This field should be a size_t, but since it is located in shared memory we
		// force to 32-bit. The client and server may have different typedefs for size_t.
		uint32_t mBufferPosition; // updated asynchronously by server,
		// position info updated asynchronously by server and read by client,
		// "for entertainment purposes only"
		StaticAudioTrackPosLoopQueue::Shared
		mPosLoopQueue;
		};

		// ----------------------------------------------------------------------------
		@@ -355,6 +374,9 @@ public:
		void setBufferPositionAndLoop(size_t position, size_t loopStart, size_t loopEnd,
		int loopCount);
		size_t getBufferPosition();
		// getBufferPositionAndLoopCount() provides the proper snapshot of
		// position and loopCount together.
		void getBufferPositionAndLoopCount(size_t position, int loopCount);

		virtual size_t getMisalignment() {
		return 0;
		@@ -366,8 +388,9 @@ public:

		private:
		StaticAudioTrackSingleStateQueue::Mutator mMutator;
		StaticAudioTrackPosLoopQueue::Observer mPosLoopObserver;
		StaticAudioTrackState mState; // last communicated state to server
		size_t mBufferPosition; // so that getBufferPosition() appears to be synchronous
		StaticAudioTrackPosLoop mPosLoop; // snapshot of position and loop.
		};

		// ----------------------------------------------------------------------------
		@@ -494,8 +517,7 @@ private:
		const StaticAudioTrackState &update) const;
		ssize_t pollPosition(); // poll for state queue update, and return current position
		StaticAudioTrackSingleStateQueue::Observer mObserver;
		size_t mPosition; // server's current play position in frames, relative to 0

		StaticAudioTrackPosLoopQueue::Mutator mPosLoopMutator;
		size_t mFramesReadySafe; // Assuming size_t read/writes are atomic on 32 / 64 bit
		// processors, this is a thread-safe version of
		// mFramesReady.

media/libmedia/AudioTrack.cpp

+26 −27

Original line number	Diff line number	Diff line
		@@ -38,6 +38,11 @@
		namespace android {
		// ---------------------------------------------------------------------------

		template <typename T>
		const T &min(const T &x, const T &y) {
		return x < y ? x : y;
		}

		static int64_t convertTimespecToUs(const struct timespec &tv)
		{
		return tv.tv_sec * 1000000ll + tv.tv_nsec / 1000;
		@@ -420,7 +425,9 @@ status_t AudioTrack::set(
		mStatus = NO_ERROR;
		mState = STATE_STOPPED;
		mUserData = user;
		mLoopPeriod = 0;
		mLoopCount = 0;
		mLoopStart = 0;
		mLoopEnd = 0;
		mMarkerPosition = 0;
		mMarkerReached = false;
		mNewPosition = 0;
		@@ -534,7 +541,6 @@ void AudioTrack::stop()

		if (mSharedBuffer != 0) {
		// clear buffer position and loop count.
		mLoopPeriod = 0;
		mStaticProxy->setBufferPositionAndLoop(0 /* position */,
		0 /* loopStart /, 0 / loopEnd /, 0 / loopCount */);
		}
		@@ -739,9 +745,11 @@ status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount

		void AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
		{
		// Setting the loop will reset next notification update period (like setPosition).
		mNewPosition = updateAndGetPosition_l() + mUpdatePeriod;
		mLoopPeriod = loopCount != 0 ? loopEnd - loopStart : 0;
		// We do not update the periodic notification point.
		// mNewPosition = updateAndGetPosition_l() + mUpdatePeriod;
		mLoopCount = loopCount;
		mLoopEnd = loopEnd;
		mLoopStart = loopStart;
		mStaticProxy->setLoop(loopStart, loopEnd, loopCount);
		}

		@@ -889,7 +897,6 @@ status_t AudioTrack::reload()
		return INVALID_OPERATION;
		}
		mNewPosition = mUpdatePeriod;
		mLoopPeriod = 0;
		(void) updateAndGetPosition_l();
		mPosition = 0;
		// The documentation is not clear on the behavior of reload() and the restoration
		@@ -1610,7 +1617,7 @@ nsecs_t AudioTrack::processAudioBuffer()
		}

		// Cache other fields that will be needed soon
		uint32_t loopPeriod = mLoopPeriod;
		uint32_t loopPeriod = mLoopCount != 0 ? mLoopEnd - mLoopStart : 0;
		uint32_t sampleRate = mSampleRate;
		uint32_t notificationFrames = mNotificationFramesAct;
		if (mRefreshRemaining) {
		@@ -1856,7 +1863,11 @@ status_t AudioTrack::restoreTrack_l(const char *from)
		}

		// save the old static buffer position
		size_t bufferPosition = mStaticProxy != NULL ? mStaticProxy->getBufferPosition() : 0;
		size_t bufferPosition = 0;
		int loopCount = 0;
		if (mStaticProxy != 0) {
		mStaticProxy->getBufferPositionAndLoopCount(&bufferPosition, &loopCount);
		}

		// If a new IAudioTrack is successfully created, createTrack_l() will modify the
		// following member variables: mAudioTrack, mCblkMemory and mCblk.
		@@ -1873,27 +1884,15 @@ status_t AudioTrack::restoreTrack_l(const char *from)
		}

		if (result == NO_ERROR) {
		// continue playback from last known position, but
		// don't attempt to restore loop after invalidation; it's difficult and not worthwhile
		if (mStaticProxy != NULL) {
		mLoopPeriod = 0;
		// Continue playback from last known position and restore loop.
		if (mStaticProxy != 0) {
		if (loopCount != 0) {
		mStaticProxy->setBufferPositionAndLoop(bufferPosition,
		0 /* loopStart /, 0 / loopEnd /, 0 / loopCount */);
		}
		// FIXME How do we simulate the fact that all frames present in the buffer at the time of
		// track destruction have been played? This is critical for SoundPool implementation
		// This must be broken, and needs to be tested/debugged.
		#if 0
		// restore write index and set other indexes to reflect empty buffer status
		if (!strcmp(from, "start")) {
		// Make sure that a client relying on callback events indicating underrun or
		// the actual amount of audio frames played (e.g SoundPool) receives them.
		if (mSharedBuffer == 0) {
		// restart playback even if buffer is not completely filled.
		android_atomic_or(CBLK_FORCEREADY, &mCblk->mFlags);
		mLoopStart, mLoopEnd, loopCount);
		} else {
		mStaticProxy->setBufferPosition(bufferPosition);
		}
		}
		#endif
		if (mState == STATE_ACTIVE) {
		result = mAudioTrack->start();
		}

media/libmedia/AudioTrackShared.cpp

+48 −19

Original line number	Diff line number	Diff line
		@@ -499,9 +499,11 @@ end:
		StaticAudioTrackClientProxy::StaticAudioTrackClientProxy(audio_track_cblk_t* cblk, void *buffers,
		size_t frameCount, size_t frameSize)
		: AudioTrackClientProxy(cblk, buffers, frameCount, frameSize),
		mMutator(&cblk->u.mStatic.mSingleStateQueue), mBufferPosition(0)
		mMutator(&cblk->u.mStatic.mSingleStateQueue),
		mPosLoopObserver(&cblk->u.mStatic.mPosLoopQueue)
		{
		memset(&mState, 0, sizeof(mState));
		memset(&mPosLoop, 0, sizeof(mPosLoop));
		}

		void StaticAudioTrackClientProxy::flush()
		@@ -523,11 +525,12 @@ void StaticAudioTrackClientProxy::setLoop(size_t loopStart, size_t loopEnd, int
		// set patch-up variables until the mState is acknowledged by the ServerProxy.
		// observed buffer position and loop count will freeze until then to give the
		// illusion of a synchronous change.
		size_t bufferPosition = getBufferPosition();
		getBufferPositionAndLoopCount(NULL, NULL);
		// preserve behavior to restart at mState.mLoopStart if position exceeds mState.mLoopEnd.
		if (loopCount != 0 && bufferPosition >= mState.mLoopEnd) {
		mBufferPosition = mState.mLoopStart;
		if (mState.mLoopCount != 0 && mPosLoop.mBufferPosition >= mState.mLoopEnd) {
		mPosLoop.mBufferPosition = mState.mLoopStart;
		}
		mPosLoop.mLoopCount = mState.mLoopCount;
		(void) mMutator.push(mState);
		}

		@@ -540,7 +543,17 @@ void StaticAudioTrackClientProxy::setBufferPosition(size_t position)
		}
		mState.mPosition = (uint32_t) position;
		mState.mPositionSequence = incrementSequence(mState.mPositionSequence, mState.mLoopSequence);
		mBufferPosition = position;
		// set patch-up variables until the mState is acknowledged by the ServerProxy.
		// observed buffer position and loop count will freeze until then to give the
		// illusion of a synchronous change.
		if (mState.mLoopCount > 0) { // only check if loop count is changing
		getBufferPositionAndLoopCount(NULL, NULL); // get last position
		}
		mPosLoop.mBufferPosition = position;
		if (position >= mState.mLoopEnd) {
		// no ongoing loop is possible if position is greater than loopEnd.
		mPosLoop.mLoopCount = 0;
		}
		(void) mMutator.push(mState);
		}

		@@ -553,18 +566,24 @@ void StaticAudioTrackClientProxy::setBufferPositionAndLoop(size_t position, size

		size_t StaticAudioTrackClientProxy::getBufferPosition()
		{
		size_t bufferPosition;
		if (mMutator.ack()) {
		// There is a race condition here as ack may be signaled before
		// the buffer position in mCblk is updated. Will be fixed in a later CL.
		bufferPosition = (size_t) mCblk->u.mStatic.mBufferPosition;
		if (bufferPosition > mFrameCount) {
		bufferPosition = mFrameCount;
		getBufferPositionAndLoopCount(NULL, NULL);
		return mPosLoop.mBufferPosition;
		}

		void StaticAudioTrackClientProxy::getBufferPositionAndLoopCount(
		size_t position, int loopCount)
		{
		if (mMutator.ack() == StaticAudioTrackSingleStateQueue::SSQ_DONE) {
		if (mPosLoopObserver.poll(mPosLoop)) {
		; // a valid mPosLoop should be available if ackDone is true.
		}
		} else {
		bufferPosition = mBufferPosition;
		}
		return bufferPosition;
		if (position != NULL) {
		*position = mPosLoop.mBufferPosition;
		}
		if (loopCount != NULL) {
		*loopCount = mPosLoop.mLoopCount;
		}
		}

		// ---------------------------------------------------------------------------
		@@ -780,7 +799,8 @@ void AudioTrackServerProxy::tallyUnderrunFrames(uint32_t frameCount)
		StaticAudioTrackServerProxy::StaticAudioTrackServerProxy(audio_track_cblk_t* cblk, void *buffers,
		size_t frameCount, size_t frameSize)
		: AudioTrackServerProxy(cblk, buffers, frameCount, frameSize),
		mObserver(&cblk->u.mStatic.mSingleStateQueue), mPosition(0),
		mObserver(&cblk->u.mStatic.mSingleStateQueue),
		mPosLoopMutator(&cblk->u.mStatic.mPosLoopQueue),
		mFramesReadySafe(frameCount), mFramesReady(frameCount),
		mFramesReadyIsCalledByMultipleThreads(false)
		{
		@@ -865,6 +885,7 @@ ssize_t StaticAudioTrackServerProxy::pollPosition()
		updateStateWithLoop(&trystate, state) == OK;
		}
		if (!result) {
		mObserver.done();
		// caution: no update occurs so server state will be inconsistent with client state.
		ALOGE("%s client pushed an invalid state, shutting down", __func__);
		mIsShutdown = true;
		@@ -883,7 +904,12 @@ ssize_t StaticAudioTrackServerProxy::pollPosition()
		}
		mFramesReadySafe = clampToSize(mFramesReady);
		// This may overflow, but client is not supposed to rely on it
		mCblk->u.mStatic.mBufferPosition = (uint32_t) mState.mPosition;
		StaticAudioTrackPosLoop posLoop;

		posLoop.mLoopCount = (int32_t) mState.mLoopCount;
		posLoop.mBufferPosition = (uint32_t) mState.mPosition;
		mPosLoopMutator.push(posLoop);
		mObserver.done(); // safe to read mStatic variables.
		}
		return (ssize_t) mState.mPosition;
		}
		@@ -969,7 +995,10 @@ void StaticAudioTrackServerProxy::releaseBuffer(Buffer* buffer)

		cblk->mServer += stepCount;
		// This may overflow, but client is not supposed to rely on it
		cblk->u.mStatic.mBufferPosition = (uint32_t) mState.mPosition;
		StaticAudioTrackPosLoop posLoop;
		posLoop.mBufferPosition = mState.mPosition;
		posLoop.mLoopCount = mState.mLoopCount;
		mPosLoopMutator.push(posLoop);
		if (setFlags != 0) {
		(void) android_atomic_or(setFlags, &cblk->mFlags);
		// this would be a good place to wake a futex