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Commit cb6cc755 authored by Andy Hung's avatar Andy Hung
Browse files

TrackMetrics: Fix volume computation 

Average volume should be weighted based on active time
not total lifetime.

Improve the numerical accuracy of average volume using
West's algorithm.

Remove unneeded variables.

Test: youtube, play/pause, adb shell dumpsys media.metrics
Bug: 233409482
Merged-In: I9fadb7287bd0bccbf5c74aad5a07eab277303d02
Change-Id: I9fadb7287bd0bccbf5c74aad5a07eab277303d02
(cherry picked from commit a81a4b4c)
parent bb52d577

services/audioflinger/TrackBase.h

+2 −0
Original line number Diff line number Diff line
@@ -397,6 +397,8 @@ protected: 
    int64_t             mLogStartFrames = 0;    // Timestamp frames at start()

    double              mLogLatencyMs = 0.;     // Track the last log latency



    bool                mLogForceVolumeUpdate = true; // force volume update to TrackMetrics.



    TrackMetrics        mTrackMetrics;



    bool                mServerLatencySupported = false;

services/audioflinger/TrackMetrics.h

+27 −28
Original line number Diff line number Diff line
@@ -64,7 +64,6 @@ public: 
                    AMEDIAMETRICS_PROP_EVENT_VALUE_BEGINAUDIOINTERVALGROUP, devices.c_str());

        }

        ++mIntervalCount;

        mIntervalStartTimeNs = systemTime();

    }



    void logConstructor(pid_t creatorPid, uid_t creatorUid, int32_t internalTrackId,
@@ -90,11 +89,9 @@ public: 
    // Called when we are removed from the Thread.

    void logEndInterval() {

        std::lock_guard l(mLock);

        if (mIntervalStartTimeNs != 0) {

            const int64_t elapsedTimeNs = systemTime() - mIntervalStartTimeNs;

            mIntervalStartTimeNs = 0;

            mCumulativeTimeNs += elapsedTimeNs;

            mDeviceTimeNs += elapsedTimeNs;

        if (mLastVolumeChangeTimeNs != 0) {

            logVolume_l(mVolume); // flush out the last volume.

            mLastVolumeChangeTimeNs = 0;

        }

    }
@@ -133,20 +130,8 @@ public: 


    // may be called multiple times during an interval

    void logVolume(float volume) {

        const int64_t timeNs = systemTime();

        std::lock_guard l(mLock);

        if (mStartVolumeTimeNs == 0) {

            mDeviceVolume = mVolume = volume;

            mLastVolumeChangeTimeNs = mStartVolumeTimeNs = timeNs;

            updateMinMaxVolume(0, mVolume);

            return;

        }

        const int64_t durationNs = timeNs - mLastVolumeChangeTimeNs;

        updateMinMaxVolume(durationNs, mVolume);

        mDeviceVolume = (mDeviceVolume * (mLastVolumeChangeTimeNs - mStartVolumeTimeNs) +

            mVolume * durationNs) / (timeNs - mStartVolumeTimeNs);

        mVolume = volume;

        mLastVolumeChangeTimeNs = timeNs;

        logVolume_l(volume);

    }



    // Use absolute numbers returned by AudioTrackShared.
@@ -158,6 +143,7 @@ public: 
    }



private:



    // no lock required - all arguments and constants.

    void deliverDeviceMetrics(const char *eventName, const char *devices) const {

        mediametrics::LogItem(mMetricsId)
@@ -167,6 +153,23 @@ private: 
           .record();

    }



    void logVolume_l(float volume) REQUIRES(mLock) {

        const int64_t timeNs = systemTime();

        const int64_t durationNs = mLastVolumeChangeTimeNs == 0

                ? 0 : timeNs - mLastVolumeChangeTimeNs;

        if (durationNs > 0) {

            // See West's algorithm for weighted averages

            // https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance

            mDeviceVolume += (mVolume - mDeviceVolume) * durationNs

                      / (durationNs + mDeviceTimeNs);

            mDeviceTimeNs += durationNs;

            mCumulativeTimeNs += durationNs;

        }

        updateMinMaxVolume(durationNs, mVolume); // always update.

        mVolume = volume;

        mLastVolumeChangeTimeNs = timeNs;

    }



    void deliverCumulativeMetrics(const char *eventName) const REQUIRES(mLock) {

        if (mIntervalCount > 0) {

            mediametrics::LogItem item(mMetricsId);
@@ -199,14 +202,12 @@ private: 
        // mDevices is not reset by resetIntervalGroupMetrics.



        mIntervalCount = 0;

        mIntervalStartTimeNs = 0;

        // mCumulativeTimeNs is not reset by resetIntervalGroupMetrics.

        mDeviceTimeNs = 0;



        mVolume = 0.f;

        mDeviceVolume = 0.f;

        mStartVolumeTimeNs = 0;

        mLastVolumeChangeTimeNs = 0;

        mLastVolumeChangeTimeNs = 0;  // last time volume logged, cleared on endInterval

        mMinVolume = AMEDIAMETRICS_INITIAL_MIN_VOLUME;

        mMaxVolume = AMEDIAMETRICS_INITIAL_MAX_VOLUME;

        mMinVolumeDurationNs = 0;
@@ -230,14 +231,12 @@ private: 


    // Number of intervals and playing time

    int32_t           mIntervalCount GUARDED_BY(mLock) = 0;

    int64_t           mIntervalStartTimeNs GUARDED_BY(mLock) = 0;

    int64_t           mCumulativeTimeNs GUARDED_BY(mLock) = 0;

    int64_t           mDeviceTimeNs GUARDED_BY(mLock) = 0;

    int64_t           mCumulativeTimeNs GUARDED_BY(mLock) = 0; // total time.

    int64_t           mDeviceTimeNs GUARDED_BY(mLock) = 0;     // time on device.



    // Average volume

    double            mVolume GUARDED_BY(mLock) = 0.f;

    double            mDeviceVolume GUARDED_BY(mLock) = 0.f;

    int64_t           mStartVolumeTimeNs GUARDED_BY(mLock) = 0;

    double            mVolume GUARDED_BY(mLock) = 0.f;       // last set volume.

    double            mDeviceVolume GUARDED_BY(mLock) = 0.f; // running average volume.

    int64_t           mLastVolumeChangeTimeNs GUARDED_BY(mLock) = 0;



    // Min/Max volume

services/audioflinger/Tracks.cpp

+6 −1
Original line number Diff line number Diff line
@@ -1123,6 +1123,7 @@ status_t AudioFlinger::PlaybackThread::Track::start(AudioSystem::sync_event_t ev 
                    .mPosition[ExtendedTimestamp::LOCATION_KERNEL];

            mLogLatencyMs = 0.;

        }

        mLogForceVolumeUpdate = true;  // at least one volume logged for metrics when starting.



        if (status == NO_ERROR || status == ALREADY_EXISTS) {

            // for streaming tracks, remove the buffer read stop limit.
@@ -1394,7 +1395,11 @@ void AudioFlinger::PlaybackThread::Track::setFinalVolume(float volume) 
    if (mFinalVolume != volume) { // Compare to an epsilon if too many meaningless updates

        mFinalVolume = volume;

        setMetadataHasChanged();

        mTrackMetrics.logVolume(volume);

        mLogForceVolumeUpdate = true;

    }

    if (mLogForceVolumeUpdate) {

        mLogForceVolumeUpdate = false;

        mTrackMetrics.logVolume(mFinalVolume);

    }

}