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Commit 4bae3649 authored by Glenn Kasten's avatar Glenn Kasten
Browse files

flush() comments and checks 

flush() is only useful for streaming mode.
It is a no-op if track is active or uses a static buffer.

Change-Id: I918ac181ffae3d16a0d67d8a7208f4aec61b5bd6
parent e4756fe3

include/media/AudioTrack.h

+8 −3
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ public: 
     * the PCM data to be rendered by AudioTrack is passed in a shared memory buffer

     * identified by the argument sharedBuffer. This prototype is for static buffer playback.

     * PCM data must be present in memory before the AudioTrack is started.

     * The write() and flush() methods are not supported in this case.

     * The write() method is not supported in this case.

     * It is recommended to pass a callback function to be notified of playback end by an

     * EVENT_UNDERRUN event.

     */
@@ -247,8 +247,10 @@ public: 
            void        stop();

            bool        stopped() const;



    /* Flush a stopped track. All pending buffers are discarded.

     * This function has no effect if the track is not stopped.

    /* Flush a stopped or paused track. All previously buffered data is discarded immediately.

     * This has the effect of draining the buffers without mixing or output.

     * Flush is intended for streaming mode, for example before switching to non-contiguous content.

     * This function is a no-op if the track is not stopped or paused, or uses a static buffer.

     */

            void        flush();
@@ -492,7 +494,10 @@ protected: 
                                 audio_output_flags_t flags,

                                 const sp<IMemory>& sharedBuffer,

                                 audio_io_handle_t output);



            // can only be called when !mActive

            void flush_l();



            status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);

            audio_io_handle_t getOutput_l();

            status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart);

media/libmedia/AudioTrack.cpp

+10 −9
Original line number Diff line number Diff line
@@ -397,6 +397,7 @@ void AudioTrack::stop() 
        mMarkerReached = false;

        // Force flush if a shared buffer is used otherwise audioflinger

        // will not stop before end of buffer is reached.

        // It may be needed to make sure that we stop playback, likely in case looping is on.

        if (mSharedBuffer != 0) {

            flush_l();

        }
@@ -419,27 +420,27 @@ bool AudioTrack::stopped() const 
void AudioTrack::flush()

{

    AutoMutex lock(mLock);

    if (!mActive && mSharedBuffer == 0) {

        flush_l();

    }

}



// must be called with mLock held

void AudioTrack::flush_l()

{

    ALOGV("flush");

    ALOG_ASSERT(!mActive);



    // clear playback marker and periodic update counter

    mMarkerPosition = 0;

    mMarkerReached = false;

    mUpdatePeriod = 0;



    if (!mActive) {

    mFlushed = true;

    mAudioTrack->flush();

    // Release AudioTrack callback thread in case it was waiting for new buffers

    // in AudioTrack::obtainBuffer()

    mCblk->cv.signal();

}

}



void AudioTrack::pause()

{