+ int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ? 0 :
+ av_rescale_rnd(c->first_timestamp, 1, stream_index >= 0 ?
+ s->streams[stream_index]->time_base.den :
+ AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
+ AV_ROUND_DOWN : AV_ROUND_UP);
+ if (var->input) {