Merge "AudioFlinger: Make Direct AudioTrack behavior more flexible for underrun" into sc-dev

// 50 * ~20msecs = 1 second

// 50 * ~20msecs = 1 second

static const int8_t kMaxTrackRetries = 50;

static const int8_t kMaxTrackRetries = 50;

static const int8_t kMaxTrackStartupRetries = 50;

static const int8_t kMaxTrackStartupRetries = 50;

// allow less retry attempts on direct output thread.

// allow less retry attempts on direct output thread.

// direct outputs can be a scarce resource in audio hardware and should

// direct outputs can be a scarce resource in audio hardware and should

// be released as quickly as possible.

// be released as quickly as possible.

static const int8_t kMaxTrackRetriesDirect = 2;

// Notes:

// 1) The retry duration kMaxTrackRetriesDirectMs may be increased

//    in case the data write is bursty for the AudioTrack.  The application

//    should endeavor to write at least once every kMaxTrackRetriesDirectMs

//    to prevent an underrun situation.  If the data is bursty, then

//    the application can also throttle the data sent to be even.

// 2) For compressed audio data, any data present in the AudioTrack buffer

//    will be sent and reset the retry count.  This delivers data as

//    it arrives, with approximately kDirectMinSleepTimeUs = 10ms checking interval.

// 3) For linear PCM or proportional PCM, we wait one period for a period's worth

//    of data to be available, then any remaining data is delivered.

//    This is required to ensure the last bit of data is delivered before underrun.

//

// Sleep time per cycle is kDirectMinSleepTimeUs for compressed tracks

// or the size of the HAL period for proportional / linear PCM tracks.

static const int32_t kMaxTrackRetriesDirectMs = 200;

// don't warn about blocked writes or record buffer overflows more often than this

// don't warn about blocked writes or record buffer overflows more often than this

static const nsecs_t kWarningThrottleNs = seconds(5);

static const nsecs_t kWarningThrottleNs = seconds(5);

        // Allow draining the buffer in case the client

        // Allow draining the buffer in case the client

        // app does not call stop() and relies on underrun to stop:

        // app does not call stop() and relies on underrun to stop:

        // hence the test on (track->mRetryCount > 1).

        // hence the test on (track->mRetryCount > 1).

        // If retryCount<=1 then track is about to underrun and be removed.

        // If track->mRetryCount <= 1 then track is about to be disabled, paused, removed,

        // so we accept any nonzero amount of data delivered by the AudioTrack (which will

        // reset the retry counter).

        // Do not use a high threshold for compressed audio.

        // Do not use a high threshold for compressed audio.

        // target retry count that we will use is based on the time we wait for retries.

        const int32_t targetRetryCount = kMaxTrackRetriesDirectMs * 1000 / mActiveSleepTimeUs;

        // the retry threshold is when we accept any size for PCM data.  This is slightly

        // smaller than the retry count so we can push small bits of data without a glitch.

        const int32_t retryThreshold = targetRetryCount > 2 ? targetRetryCount - 1 : 1;

        uint32_t minFrames;

        uint32_t minFrames;

        if ((track->sharedBuffer() == 0) && !track->isStopping_1() && !track->isPausing()

        if ((track->sharedBuffer() == 0) && !track->isStopping_1() && !track->isPausing()

            && (track->mRetryCount > 1) && audio_has_proportional_frames(mFormat)) {

            && (track->mRetryCount > retryThreshold) && audio_has_proportional_frames(mFormat)) {

            minFrames = mNormalFrameCount;

            minFrames = mNormalFrameCount;

        } else {

        } else {

            minFrames = 1;

            minFrames = 1;

                mPreviousTrack = track;

                mPreviousTrack = track;

                // reset retry count

                // reset retry count

                track->mRetryCount = kMaxTrackRetriesDirect;

                track->mRetryCount = targetRetryCount;

                mActiveTrack = t;

                mActiveTrack = t;

                mixerStatus = MIXER_TRACKS_READY;

                mixerStatus = MIXER_TRACKS_READY;

                if (mHwPaused) {

                if (mHwPaused) {