_FrameRate
double _FrameRate() const;
/ _FrameRate());
int64(fCurrentTime * _FrameRate() / 1000000.0 + 0.5),
fCurrentTime / 1000000.0, (float)fCurrentFrame / _FrameRate());
fCurrentFrame = (int64)(fCurrentTime * _FrameRate() / 1000000LL);