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Commit 53c3b5fc authored by Andy Hung's avatar Andy Hung
Browse files

Improve AudioTrack EVENT_LOOP_END and EVENT_BUFFER_END accuracy 

Fix timing computation to consider current position.
Fix EVENT_LOOP_END count accuracy (some could be dropped before)
for non-infinite loop static AudioTracks.

Change-Id: I255f692915b55ab6f08ccd6a2365fee3f5d0a4fe
parent 4ede21d9

include/media/AudioTrack.h

+4 −0
Original line number Diff line number Diff line
@@ -736,6 +736,10 @@ protected: 
    int32_t                 mLoopCount;             // last setLoop loopCount; zero means disabled

    uint32_t                mLoopStart;             // last setLoop loopStart

    uint32_t                mLoopEnd;               // last setLoop loopEnd

    int32_t                 mLoopCountNotified;     // the last loopCount notified by callback.

                                                    // mLoopCountNotified counts down, matching

                                                    // the remaining loop count for static track

                                                    // playback.



    // These are private to processAudioBuffer(), and are not protected by a lock

    uint32_t                mRemainingFrames;       // number of frames to request in obtainBuffer()

media/libmedia/AudioTrack.cpp

+40 −11
Original line number Diff line number Diff line
@@ -33,7 +33,7 @@ 


#define WAIT_PERIOD_MS                  10

#define WAIT_STREAM_END_TIMEOUT_SEC     120



static const int kMaxLoopCountNotifications = 32;



namespace android {

// ---------------------------------------------------------------------------
@@ -428,6 +428,7 @@ status_t AudioTrack::set( 
    mLoopCount = 0;

    mLoopStart = 0;

    mLoopEnd = 0;

    mLoopCountNotified = 0;

    mMarkerPosition = 0;

    mMarkerReached = false;

    mNewPosition = 0;
@@ -750,6 +751,7 @@ void AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount) 
    mLoopCount = loopCount;

    mLoopEnd = loopEnd;

    mLoopStart = loopStart;

    mLoopCountNotified = loopCount;

    mStaticProxy->setLoop(loopStart, loopEnd, loopCount);

}
@@ -899,10 +901,15 @@ status_t AudioTrack::reload() 
    mNewPosition = mUpdatePeriod;

    (void) updateAndGetPosition_l();

    mPosition = 0;

#if 0

    // The documentation is not clear on the behavior of reload() and the restoration

    // of loop count. Historically we have not restored loop count, start, end;

    // rather we just reset the buffer position.  However, restoring the last setLoop

    // information makes sense if one desires to repeat playing a particular sound.

    // of loop count. Historically we have not restored loop count, start, end,

    // but it makes sense if one desires to repeat playing a particular sound.

    if (mLoopCount != 0) {

        mLoopCountNotified = mLoopCount;

        mStaticProxy->setLoop(mLoopStart, mLoopEnd, mLoopCount);

    }

#endif

    mStaticProxy->setBufferPosition(0);

    return NO_ERROR;

}
@@ -1566,9 +1573,8 @@ nsecs_t AudioTrack::processAudioBuffer() 
        // that the upper layers can recreate the track

        if (!isOffloadedOrDirect_l() || (mSequence == mObservedSequence)) {

            status_t status = restoreTrack_l("processAudioBuffer");

            mLock.unlock();

            // Run again immediately, but with a new IAudioTrack

            return 0;

            // after restoration, continue below to make sure that the loop and buffer events

            // are notified because they have been cleared from mCblk->mFlags above.

        }

    }
@@ -1617,7 +1623,6 @@ nsecs_t AudioTrack::processAudioBuffer() 
    }



    // Cache other fields that will be needed soon

    uint32_t loopPeriod = mLoopCount != 0 ? mLoopEnd - mLoopStart : 0;

    uint32_t sampleRate = mSampleRate;

    uint32_t notificationFrames = mNotificationFramesAct;

    if (mRefreshRemaining) {
@@ -1629,6 +1634,28 @@ nsecs_t AudioTrack::processAudioBuffer() 
    uint32_t sequence = mSequence;

    sp<AudioTrackClientProxy> proxy = mProxy;



    // Determine the number of new loop callback(s) that will be needed, while locked.

    int loopCountNotifications = 0;

    uint32_t loopPeriod = 0; // time in frames for next EVENT_LOOP_END or EVENT_BUFFER_END



    if (mLoopCount > 0) {

        int loopCount;

        size_t bufferPosition;

        mStaticProxy->getBufferPositionAndLoopCount(&bufferPosition, &loopCount);

        loopPeriod = ((loopCount > 0) ? mLoopEnd : mFrameCount) - bufferPosition;

        loopCountNotifications = min(mLoopCountNotified - loopCount, kMaxLoopCountNotifications);

        mLoopCountNotified = loopCount; // discard any excess notifications

    } else if (mLoopCount < 0) {

        // FIXME: We're not accurate with notification count and position with infinite looping

        // since loopCount from server side will always return -1 (we could decrement it).

        size_t bufferPosition = mStaticProxy->getBufferPosition();

        loopCountNotifications = int((flags & (CBLK_LOOP_CYCLE | CBLK_LOOP_FINAL)) != 0);

        loopPeriod = mLoopEnd - bufferPosition;

    } else if (/* mLoopCount == 0 && */ mSharedBuffer != 0) {

        size_t bufferPosition = mStaticProxy->getBufferPosition();

        loopPeriod = mFrameCount - bufferPosition;

    }



    // These fields don't need to be cached, because they are assigned only by set():

    //     mTransfer, mCbf, mUserData, mFormat, mFrameSize, mFrameSizeAF, mFlags

    // mFlags is also assigned by createTrack_l(), but not the bit we care about.
@@ -1669,10 +1696,9 @@ nsecs_t AudioTrack::processAudioBuffer() 
    if (newUnderrun) {

        mCbf(EVENT_UNDERRUN, mUserData, NULL);

    }

    // FIXME we will miss loops if loop cycle was signaled several times since last call

    //       to processAudioBuffer()

    if (flags & (CBLK_LOOP_CYCLE | CBLK_LOOP_FINAL)) {

    while (loopCountNotifications > 0) {

        mCbf(EVENT_LOOP_END, mUserData, NULL);

        --loopCountNotifications;

    }

    if (flags & CBLK_BUFFER_END) {

        mCbf(EVENT_BUFFER_END, mUserData, NULL);
@@ -1891,6 +1917,9 @@ status_t AudioTrack::restoreTrack_l(const char *from) 
                        mLoopStart, mLoopEnd, loopCount);

            } else {

                mStaticProxy->setBufferPosition(bufferPosition);

                if (bufferPosition == mFrameCount) {

                    ALOGD("restoring track at end of static buffer");

                }

            }

        }

        if (mState == STATE_ACTIVE) {