Merge "stagefright: rtsp: handle overflow in jitter calculation" into main

    int64_t scheduledTimeUs = ((int32_t)diff) * 1000000ll / mClockRate;

    int64_t elapsedTimeUs = arrivalTimeUs - mFirstArrivalTimeUs;

    int64_t correctionTimeUs = elapsedTimeUs - scheduledTimeUs; // additional propagation delay;

    mBaseJitterUs = (mBaseJitterUs * 15 + correctionTimeUs) / 16;

    // We want to approximate correctionTimeUs by slowly (1:15) averaging into jitter base, but

    // both correction time and base jitter can roll over. Adjust correctionTime to be close to

    // base jitter. Accomplish this by calculating the closest 32-bit delta (positive or

    // negative) and applying 1/16th of it to the base jitter.

    int32_t correctionDiff;

    (void)__builtin_sub_overflow(correctionTimeUs, mBaseJitterUs, &correctionDiff);

    mBaseJitterUs = int32_t(int64_t(mBaseJitterUs) + correctionDiff / 16);

    ALOGV("BaseJitterUs : %lld \t\t correctionTimeUs : %lld",

            (long long)mBaseJitterUs, (long long)correctionTimeUs);

}