Hi, r16159 was this: - if (!ost->frame_number && !(pkt->flags & PKT_FLAG_KEY)) + if ((!ost->frame_number && !(pkt->flags & PKT_FLAG_KEY)) && start_time) However, start_time is always 0 here (cf. ffmpeg.c:2811), so this has unconditionally disabled the skipping of non-keyframes. What exactly did this fix? Regards, Wolfram.