int64_t pres_time = av_rescale_q(c->start, c->time_base, scale);
uint64_t offset;
int32_t send_time = get_send_time(asf, pres_time, &offset);
int64_t pres_time = av_rescale_q(c->start, c->time_base, scale);
uint64_t offset;
int32_t send_time = get_send_time(asf, pres_time, &offset);