Merge "MPEG4Write mdhd duration overflow after recording for 15 hours"

void MPEG4Writer::Track::writeMdhdBox(uint32_t now) {

    int64_t trakDurationUs = getDurationUs();

    int64_t mdhdDuration = (trakDurationUs * mTimeScale + 5E5) / 1E6;

    mOwner->beginBox("mdhd");

    if (mdhdDuration > UINT32_MAX) {

        mOwner->writeInt32((1 << 24));            // version=1, flags=0

        mOwner->writeInt64((int64_t)now);         // creation time

        mOwner->writeInt64((int64_t)now);         // modification time

        mOwner->writeInt32(mTimeScale);           // media timescale

        mOwner->writeInt64(mdhdDuration);         // media timescale

    } else {

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

        mOwner->writeInt32(now);                    // creation time

        mOwner->writeInt32(now);                    // modification time

        mOwner->writeInt32(mTimeScale);             // media timescale

    int32_t mdhdDuration = (trakDurationUs * mTimeScale + 5E5) / 1E6;

    mOwner->writeInt32(mdhdDuration);  // use media timescale

        mOwner->writeInt32((int32_t)mdhdDuration);  // use media timescale

    }

    // Language follows the three letter standard ISO-639-2/T

    // 'e', 'n', 'g' for "English", for instance.

    // Each character is packed as the difference between its ASCII value and 0x60.