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Commit 30d28422 authored by Dean Wheatley's avatar Dean Wheatley Committed by Mikhail Naganov
Browse files

Offset direct/offload timestamps by downstream latency 

Test: A/V sync of direct/offload DD+ non HW A/V sync playback thread
      through MSD, and MSD -> Audio HAL patch in DD+ non HW A/V sync
      mode.
Change-Id: I244e9fda9741fe9a9ea913f39901654ebefb973c
(cherry picked from commit 8729c2eb3eabda3f6b6985a113bd2022b5b379c9)
parent 0332f621

services/audioflinger/Threads.cpp

+14 −6
Original line number Diff line number Diff line
@@ -3185,7 +3185,6 @@ bool AudioFlinger::PlaybackThread::threadLoop() 
    if (mType == OFFLOAD || mType == DIRECT) {

        mTimestampVerifier.setDiscontinuityMode(mTimestampVerifier.DISCONTINUITY_MODE_ZERO);

    }

    audio_utils::Statistics<double> downstreamLatencyStatMs(0.999 /* alpha */);

    audio_patch_handle_t lastDownstreamPatchHandle = AUDIO_PATCH_HANDLE_NONE;



    while (!exitPending())
@@ -3215,7 +3214,7 @@ bool AudioFlinger::PlaybackThread::threadLoop() 
                        downstreamPatchHandle = swPatches[0].getPatchHandle();

                }

                if (downstreamPatchHandle != lastDownstreamPatchHandle) {

                    downstreamLatencyStatMs.reset();

                    mDownstreamLatencyStatMs.reset();

                    lastDownstreamPatchHandle = downstreamPatchHandle;

                }

                if (status == OK) {
@@ -3229,14 +3228,14 @@ bool AudioFlinger::PlaybackThread::threadLoop() 
                        if (latencyMs < minLatency) latencyMs = minLatency;

                        else if (latencyMs > maxLatency) latencyMs = maxLatency;

                    }

                    downstreamLatencyStatMs.add(latencyMs);

                    mDownstreamLatencyStatMs.add(latencyMs);

                }

                mAudioFlinger->mLock.unlock();

            }

        } else {

            if (lastDownstreamPatchHandle != AUDIO_PATCH_HANDLE_NONE) {

                // our device is no longer AUDIO_DEVICE_OUT_BUS, reset patch handle and stats.

                downstreamLatencyStatMs.reset();

                mDownstreamLatencyStatMs.reset();

                lastDownstreamPatchHandle = AUDIO_PATCH_HANDLE_NONE;

            }

        }
@@ -3285,10 +3284,10 @@ bool AudioFlinger::PlaybackThread::threadLoop() 
                            (long long)timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL]);



                    // Note: Downstream latency only added if timestamp correction enabled.

                    if (downstreamLatencyStatMs.getN() > 0) { // we have latency info.

                    if (mDownstreamLatencyStatMs.getN() > 0) { // we have latency info.

                        const int64_t newPosition =

                                timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL]

                                - int64_t(downstreamLatencyStatMs.getMean() * mSampleRate * 1e-3);

                                - int64_t(mDownstreamLatencyStatMs.getMean() * mSampleRate * 1e-3);

                        // prevent retrograde

                        timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = max(

                                newPosition,
@@ -3747,6 +3746,15 @@ status_t AudioFlinger::PlaybackThread::getTimestamp_l(AudioTimestamp& timestamp) 
        uint64_t position64;

        if (mOutput->getPresentationPosition(&position64, &timestamp.mTime) == OK) {

            timestamp.mPosition = (uint32_t)position64;

            if (mDownstreamLatencyStatMs.getN() > 0) {

                const uint32_t positionOffset =

                    (uint32_t)(mDownstreamLatencyStatMs.getMean() * mSampleRate * 1e-3);

                if (positionOffset > timestamp.mPosition) {

                    timestamp.mPosition = 0;

                } else {

                    timestamp.mPosition -= positionOffset;

                }

            }

            return NO_ERROR;

        }

    }

services/audioflinger/Threads.h

+2 −0
Original line number Diff line number Diff line
@@ -1082,6 +1082,8 @@ private: 
    static const size_t     kFastMixerLogSize = 8 * 1024;

    sp<NBLog::Writer>       mFastMixerNBLogWriter;



    // Downstream patch latency, available if mDownstreamLatencyStatMs.getN() > 0.

    audio_utils::Statistics<double> mDownstreamLatencyStatMs{0.999};



public:

    virtual     bool        hasFastMixer() const = 0;