// the check for tb_unreliable() is not completely correct, since this is not about handling
// a unreliable/inexact time base, but a time base that is finer than necessary, as e.g.
// ipmovie.c produces.
- if (tb_unreliable(st->codec) && st->info->duration_count > 15 && st->info->duration_gcd > 1 && !st->r_frame_rate.num)
+ if (tb_unreliable(st->codec) && st->info->duration_count > 15 && st->info->duration_gcd > FFMAX(1, st->time_base.den/(500LL*st->time_base.num)) && !st->r_frame_rate.num)
av_reduce(&st->r_frame_rate.num, &st->r_frame_rate.den, st->time_base.den, st->time_base.num * st->info->duration_gcd, INT_MAX);
if (st->info->duration_count && !st->r_frame_rate.num
&& tb_unreliable(st->codec) /*&&