frac_add          643 libavformat/mux.c             frac_add(st->internal->priv_pts, (int64_t)st->time_base.den * frame_size);
frac_add          647 libavformat/mux.c         frac_add(st->internal->priv_pts, (int64_t)st->time_base.den * st->time_base.num);