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Commit eff30e3d authored by James Dong's avatar James Dong
Browse files

Change the default time scale for audio/video track during recording 

and reduce rounding errors in calculating the sample duration

- Default time scale for tracks other than audio is set to 90000.
- Audio track by default uses the audio sampling rate as the time scale.
- Default movie time scale remains to be 1000.
- The default time scale values will be overwritten by a user-supplied value if exits.

Change-Id: I81b40ed0626ea45e9fd24a89e21a2c5a4a2c3415
parent 997dc32b

media/libmediaplayerservice/StagefrightRecorder.cpp

+12 −6
Original line number Diff line number Diff line
@@ -675,7 +675,9 @@ sp<MediaSource> StagefrightRecorder::createAudioSource() { 
    encMeta->setInt32(kKeyChannelCount, mAudioChannels);

    encMeta->setInt32(kKeySampleRate, mSampleRate);

    encMeta->setInt32(kKeyBitRate, mAudioBitRate);

    if (mAudioTimeScale > 0) {

        encMeta->setInt32(kKeyTimeScale, mAudioTimeScale);

    }



    OMXClient client;

    CHECK_EQ(client.connect(), OK);
@@ -961,7 +963,9 @@ status_t StagefrightRecorder::setupVideoEncoder(sp<MediaSource> *source) { 
    enc_meta->setInt32(kKeyStride, stride);

    enc_meta->setInt32(kKeySliceHeight, sliceHeight);

    enc_meta->setInt32(kKeyColorFormat, colorFormat);

    if (mVideoTimeScale > 0) {

        enc_meta->setInt32(kKeyTimeScale, mVideoTimeScale);

    }

    if (mVideoEncoderProfile != -1) {

        enc_meta->setInt32(kKeyVideoProfile, mVideoEncoderProfile);

    }
@@ -1041,7 +1045,9 @@ status_t StagefrightRecorder::startMPEG4Recording() { 
    meta->setInt32(kKeyFileType, mOutputFormat);

    meta->setInt32(kKeyBitRate, totalBitRate);

    meta->setInt32(kKey64BitFileOffset, mUse64BitFileOffset);

    if (mMovieTimeScale > 0) {

        meta->setInt32(kKeyTimeScale, mMovieTimeScale);

    }

    if (mTrackEveryTimeDurationUs > 0) {

        meta->setInt64(kKeyTrackTimeStatus, mTrackEveryTimeDurationUs);

    }
@@ -1117,9 +1123,9 @@ status_t StagefrightRecorder::reset() { 
    mIFramesIntervalSec = 1;

    mAudioSourceNode = 0;

    mUse64BitFileOffset = false;

    mMovieTimeScale  = 1000;

    mAudioTimeScale  = 1000;

    mVideoTimeScale  = 1000;

    mMovieTimeScale  = -1;

    mAudioTimeScale  = -1;

    mVideoTimeScale  = -1;

    mCameraId        = 0;

    mVideoEncoderProfile = -1;

    mVideoEncoderLevel   = -1;

media/libstagefright/MPEG4Writer.cpp

+51 −8
Original line number Diff line number Diff line
@@ -168,6 +168,12 @@ private: 


    void getCodecSpecificDataFromInputFormatIfPossible();



    // Determine the track time scale

    // If it is an audio track, try to use the sampling rate as

    // the time scale; however, if user chooses the overwrite

    // value, the user-supplied time scale will be used.

    void setTimeScale();



    Track(const Track &);

    Track &operator=(const Track &);

};
@@ -434,7 +440,7 @@ void MPEG4Writer::stop() { 
    mMoovBoxBuffer = (uint8_t *) malloc(mEstimatedMoovBoxSize);

    mMoovBoxBufferOffset = 0;

    CHECK(mMoovBoxBuffer != NULL);

    int32_t duration = (maxDurationUs * mTimeScale) / 1E6;

    int32_t duration = (maxDurationUs * mTimeScale + 5E5) / 1E6;



    beginBox("moov");
@@ -749,10 +755,6 @@ MPEG4Writer::Track::Track( 
      mReachedEOS(false) {

    getCodecSpecificDataFromInputFormatIfPossible();



    if (!mMeta->findInt32(kKeyTimeScale, &mTimeScale)) {

        mTimeScale = 1000;

    }



    const char *mime;

    mMeta->findCString(kKeyMIMEType, &mime);

    mIsAvc = !strcasecmp(mime, MEDIA_MIMETYPE_VIDEO_AVC);
@@ -760,6 +762,28 @@ MPEG4Writer::Track::Track( 
    mIsMPEG4 = !strcasecmp(mime, MEDIA_MIMETYPE_VIDEO_MPEG4) ||

               !strcasecmp(mime, MEDIA_MIMETYPE_AUDIO_AAC);



    setTimeScale();

}



void MPEG4Writer::Track::setTimeScale() {

    LOGV("setTimeScale");

    // Default time scale

    mTimeScale = 90000;



    if (mIsAudio) {

        // Use the sampling rate as the default time scale for audio track.

        int32_t sampleRate;

        bool success = mMeta->findInt32(kKeySampleRate, &sampleRate);

        CHECK(success);

        mTimeScale = sampleRate;

    }



    // If someone would like to overwrite the timescale, use user-supplied value.

    int32_t timeScale;

    if (mMeta->findInt32(kKeyTimeScale, &timeScale)) {

        mTimeScale = timeScale;

    }



    CHECK(mTimeScale > 0);

}
@@ -1336,6 +1360,8 @@ void MPEG4Writer::Track::threadEntry() { 
    int32_t nZeroLengthFrames = 0;

    int64_t lastTimestampUs = 0;  // Previous sample time stamp in ms

    int64_t lastDurationUs = 0;   // Between the previous two samples in ms

    int64_t currDurationTicks = 0;  // Timescale based ticks

    int64_t lastDurationTicks = 0;  // Timescale based ticks

    int32_t sampleCount = 1;      // Sample count in the current stts table entry

    uint32_t previousSampleSize = 0;  // Size of the previous sample

    int64_t previousPausedDurationUs = 0;
@@ -1483,7 +1509,16 @@ void MPEG4Writer::Track::threadEntry() { 
        mSampleSizes.push_back(sampleSize);

        ++mNumSamples;

        if (mNumSamples > 2) {

            if (lastDurationUs != timestampUs - lastTimestampUs) {

            // We need to use the time scale based ticks, rather than the

            // timestamp itself to determine whether we have to use a new

            // stts entry, since we may have rounding errors.

            // The calculation is intended to reduce the accumulated

            // rounding errors.

            currDurationTicks =

                     ((timestampUs * mTimeScale + 500000LL) / 1000000LL -

                     (lastTimestampUs * mTimeScale + 500000LL) / 1000000LL);



            if (currDurationTicks != lastDurationTicks) {

                SttsTableEntry sttsEntry(sampleCount, lastDurationUs);

                mSttsTableEntries.push_back(sttsEntry);

                sampleCount = 1;
@@ -1498,6 +1533,7 @@ void MPEG4Writer::Track::threadEntry() { 
            previousSampleSize = sampleSize;

        }

        lastDurationUs = timestampUs - lastTimestampUs;

        lastDurationTicks = currDurationTicks;

        lastTimestampUs = timestampUs;

        if (mIsRealTimeRecording && mIsAudio) {

            wallClockTimeUs = systemTime() / 1000;
@@ -1774,7 +1810,6 @@ void MPEG4Writer::Track::writeTrackHeader( 
    LOGV("%s track time scale: %d",

        mIsAudio? "Audio": "Video", mTimeScale);





    time_t now = time(NULL);

    int32_t mvhdTimeScale = mOwner->getTimeScale();

    int64_t trakDurationUs = getDurationUs();
@@ -2089,10 +2124,18 @@ void MPEG4Writer::Track::writeTrackHeader( 
          mOwner->beginBox("stts");

            mOwner->writeInt32(0);  // version=0, flags=0

            mOwner->writeInt32(mSttsTableEntries.size());

            int64_t prevTimestampUs = 0;

            for (List<SttsTableEntry>::iterator it = mSttsTableEntries.begin();

                 it != mSttsTableEntries.end(); ++it) {

                mOwner->writeInt32(it->sampleCount);

                int32_t dur = (it->sampleDurationUs * mTimeScale + 5E5) / 1E6;



                // Make sure that we are calculating the sample duration the exactly

                // same way as we made decision on how to create stts entries.

                int64_t currTimestampUs = prevTimestampUs + it->sampleDurationUs;

                int32_t dur = ((currTimestampUs * mTimeScale + 500000LL) / 1000000LL -

                               (prevTimestampUs * mTimeScale + 500000LL) / 1000000LL);

                prevTimestampUs += (it->sampleCount * it->sampleDurationUs);



                mOwner->writeInt32(dur);

            }

          mOwner->endBox();  // stts