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Commit e8972b0a authored by Phil Burk's avatar Phil Burk
Browse files

AudioTrack: fix stall if setBufferSizeInFrames() called before play() 



The server was waiting for a full buffer.
But the buffer was only getting partly filled.
So the stream was not starting.

The fix involves having the server look at the adjustable threshold.

Bug: 27505889
Change-Id: I5dbf686413e670dacbbecc9e0f838744e465f44f
Signed-off-by: default avatarPhil Burk <philburk@google.com>
parent f56a02a5

include/private/media/AudioTrackShared.h

+15 −8
Original line number Diff line number Diff line
@@ -177,6 +177,10 @@ private: 
                // server write-only, client read

                ExtendedTimestampQueue::Shared mExtendedTimestampQueue;



                // This is set by AudioTrack.setBufferSizeInFrames().

                // A write will not fill the buffer above this limit.

    volatile    uint32_t   mBufferSizeInFrames;  // effective size of the buffer



public:



    volatile    int32_t     mFlags;         // combinations of CBLK_*
@@ -312,9 +316,9 @@ public: 
        return mEpoch;

    }



    size_t      getBufferSizeInFrames() const { return mBufferSizeInFrames; }

    // See documentation for AudioTrack.setBufferSizeInFrames()

    size_t      setBufferSizeInFrames(size_t requestedSize);

    uint32_t      getBufferSizeInFrames() const { return mBufferSizeInFrames; }

    // See documentation for AudioTrack::setBufferSizeInFrames()

    uint32_t      setBufferSizeInFrames(uint32_t requestedSize);



    status_t    getTimestamp(ExtendedTimestamp *timestamp) {

        if (timestamp == nullptr) {
@@ -329,12 +333,10 @@ public: 
        mTimestamp.clear();

    }



protected:

    // This is set by AudioTrack.setBufferSizeInFrames().

    // A write will not fill the buffer above this limit.

    size_t      mBufferSizeInFrames;      // effective size of the buffer



private:

    // This is a copy of mCblk->mBufferSizeInFrames

    uint32_t   mBufferSizeInFrames;  // effective size of the buffer



    Modulo<uint32_t> mEpoch;



    // The shared buffer contents referred to by the timestamp observer
@@ -518,6 +520,11 @@ public: 
        mTimestampMutator.push(timestamp);

    }



    // Get dynamic buffer size from the shared control block.

    uint32_t            getBufferSizeInFrames() const {

        return android_atomic_acquire_load((int32_t *)&mCblk->mBufferSizeInFrames);

    }



protected:

    size_t      mAvailToClient; // estimated frames available to client prior to releaseBuffer()

    int32_t     mFlush;         // our copy of cblk->u.mStreaming.mFlush, for streaming output only

media/libmedia/AudioTrack.cpp

+2 −5
Original line number Diff line number Diff line
@@ -860,7 +860,7 @@ ssize_t AudioTrack::getBufferSizeInFrames() 
    if (mOutput == AUDIO_IO_HANDLE_NONE || mProxy.get() == 0) {

        return NO_INIT;

    }

    return mProxy->getBufferSizeInFrames();

    return (ssize_t) mProxy->getBufferSizeInFrames();

}



ssize_t AudioTrack::setBufferSizeInFrames(size_t bufferSizeInFrames)
@@ -873,10 +873,7 @@ ssize_t AudioTrack::setBufferSizeInFrames(size_t bufferSizeInFrames) 
    if (!audio_is_linear_pcm(mFormat)) {

        return INVALID_OPERATION;

    }

    // TODO also need to inform the server side (through mAudioTrack) that

    // the buffer count is reduced, otherwise the track may never start

    // because the server thinks it is never filled.

    return mProxy->setBufferSizeInFrames(bufferSizeInFrames);

    return (ssize_t) mProxy->setBufferSizeInFrames((uint32_t) bufferSizeInFrames);

}



status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)

media/libmedia/AudioTrackShared.cpp

+27 −18
Original line number Diff line number Diff line
@@ -46,8 +46,10 @@ static uint32_t incrementSequence(uint32_t self, uint32_t other) { 
}



audio_track_cblk_t::audio_track_cblk_t()

    : mServer(0), mFutex(0), mMinimum(0),

    mVolumeLR(GAIN_MINIFLOAT_PACKED_UNITY), mSampleRate(0), mSendLevel(0), mFlags(0)

    : mServer(0), mFutex(0), mMinimum(0)

    , mVolumeLR(GAIN_MINIFLOAT_PACKED_UNITY), mSampleRate(0), mSendLevel(0)

    , mBufferSizeInFrames(0)

    , mFlags(0)

{

    memset(&u, 0, sizeof(u));

}
@@ -67,10 +69,10 @@ Proxy::Proxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCount, size_t 
ClientProxy::ClientProxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCount,

        size_t frameSize, bool isOut, bool clientInServer)

    : Proxy(cblk, buffers, frameCount, frameSize, isOut, clientInServer)

    , mBufferSizeInFrames(frameCount)

    , mEpoch(0)

    , mTimestampObserver(&cblk->mExtendedTimestampQueue)

{

    setBufferSizeInFrames(frameCount);

}



const struct timespec ClientProxy::kForever = {INT_MAX /*tv_sec*/, 0 /*tv_nsec*/};
@@ -84,6 +86,26 @@ const struct timespec ClientProxy::kNonBlocking = {0 /*tv_sec*/, 0 /*tv_nsec*/}; 
// order of minutes.

#define MAX_SEC    5



uint32_t ClientProxy::setBufferSizeInFrames(uint32_t size)

{

    // TODO set minimum to 2X the fast mixer buffer size.

    // The minimum should be  greater than zero and less than the size

    // at which underruns will occur.

    const uint32_t minimum = 128 * 2; // arbitrary

    const uint32_t maximum = frameCount();

    uint32_t clippedSize = size;

    if (clippedSize < minimum) {

        clippedSize = minimum;

    } else if (clippedSize > maximum) {

        clippedSize = maximum;

    }

    // for server to read

    android_atomic_release_store(clippedSize, (int32_t *)&mCblk->mBufferSizeInFrames);

    // for client to read

    mBufferSizeInFrames = clippedSize;

    return clippedSize;

}



status_t ClientProxy::obtainBuffer(Buffer* buffer, const struct timespec *requested,

        struct timespec *elapsed)

{
@@ -174,7 +196,7 @@ status_t ClientProxy::obtainBuffer(Buffer* buffer, const struct timespec *reques 
        // The calculation for avail can go negative if the buffer size

        // is suddenly dropped below the amount already in the buffer.

        // So use a signed calculation to prevent a numeric overflow abort.

        ssize_t adjustableSize = (ssize_t) mBufferSizeInFrames;

        ssize_t adjustableSize = (ssize_t) getBufferSizeInFrames();

        ssize_t avail =  (mIsOut) ? adjustableSize - filled : filled;

        if (avail < 0) {

            avail = 0;
@@ -357,20 +379,6 @@ size_t ClientProxy::getMisalignment() 
            (mFrameCountP2 - 1);

}



size_t ClientProxy::setBufferSizeInFrames(size_t size)

{

    // TODO set minimum to 2X the fast mixer buffer size.

    size_t minimum = 128 * 2; // arbitrary

    size_t maximum = frameCount();

    if (size < minimum) {

        size = minimum;

    } else if (size > maximum) {

        size = maximum;

    }

    mBufferSizeInFrames = size;

    return size;

}



// ---------------------------------------------------------------------------



void AudioTrackClientProxy::flush()
@@ -601,6 +609,7 @@ ServerProxy::ServerProxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCo 
      mAvailToClient(0), mFlush(0), mReleased(0)

    , mTimestampMutator(&cblk->mExtendedTimestampQueue)

{

    cblk->mBufferSizeInFrames = frameCount;

}



status_t ServerProxy::obtainBuffer(Buffer* buffer, bool ackFlush)

services/audioflinger/Tracks.cpp

+1 −1
Original line number Diff line number Diff line
@@ -617,7 +617,7 @@ bool AudioFlinger::PlaybackThread::Track::isReady() const { 
        return true;

    }



    if (framesReady() >= mFrameCount ||

    if (framesReady() >= mServerProxy->getBufferSizeInFrames() ||

            (mCblk->mFlags & CBLK_FORCEREADY)) {

        mFillingUpStatus = FS_FILLED;

        android_atomic_and(~CBLK_FORCEREADY, &mCblk->mFlags);