keyframes not on scene change

[philtre]

I remember always being able to cut up a DivX4 file on scene changes. This isn't the case with XviDs that I encode myself. Why is it that keyframes appear in very weird places. Does it have to do with B-frames? I use the recommended encoding settings from Nic's site and VirtualDub for encoding.

[FullAction]

I got the same and I wasn't using B-frames. It looks it happens mostly in a bitrate limited scenario, visible by blockiness after a scene change, which goes away 1-2 seconds after the scene change.

[symonjfox]

@ philtre

I think that is because if you use B frames and disable DivX 5 bframes compatibility, I noticed that VDub doesn't find I frames so well. I'll make more testing but I had the same problem with Xvid. It's due to AVI format that doesn't support B frames so there are some workarounds (like this).

@ developers:

Is it possible to increase the scene change thresold? It would be a workaround for I frames known bug (that doesn't respect the max I frames interval).

[sungey]

from Umaniac's changelog

XviD.Alpha.20.03.2003.0940.exe
U xvidcore/src/encoder.c (rev.1.96) syskin:
- some cleanups ; revised p/b decision with sensitivity control ; max iframe interval works again

i think the keyframe issue in b-frame encode has been fixed. I dont know if different flavors of xvid (koepi,nic) have certain changes that affect the max keyframe interval again.