DivX/AC3 playback problems

[Demi-god]

Me and my friend are having problems with divx movies with ac3 sound. The sound does play back fine but the video runs too fast for some reason. I used different players to make sure that wasn't an issue. Zoomplayer provided useful information: the "actual" fps was 3-4fps higher than the specified fps(25.000) so the video gets desynced. If I play back the soundless avi I get exactly 25.000fps as the actual framerate. I've always had this problem using direct ac3 passthrough to my amplifier but I could circumvent the problem by checking the "AC-3 Decode" checkbox in Audigy's surround mixer and setting up 6ch analog output to my amplifier. I watched one of my home-made rips fully and witnessed no AV desynch. Yesterday however, my friend said he could not get a video to synch no matter what he did. I verified this problem on my own box: no matter what settings I use the video still played too fast. I even tried to remux it, but that didn't help either.
So: how come I haven't heard of this problem earlier anywhere? Is AC3 working for everyone? Does ANYONE know how to fix this problem? Or even what _causes_ this?

Background info:
Muxer program: Nandub 1.0rc2
Video codec: DivX Pro 5.01
Sound card: Audigy player (SBLive! Value)
CPU: Athlon XP 1700+ (Athlon 1200MHz)
OS: Windows XP Pro

[wingcom]

I'm having the same problem but not only with AC3 encoded movies. All my movies worked perfect until I started searching for a codec to playback audio for Stargate[amc] Rips (whatever [amc] is, i'm not yet known with ripping). Anyways, after installing the AC3 codec the sound worked fine, except for the first pilot-episode which was not [amc]. At this moment i started installing and uninstalling codecs and totally screwed up my whole system.
Now audio and video are desynched for all my movies...
Basicly I have an AC3 codec, Divx5.01 PRO bundle and use PowerDivx 3.12 to playback movies (but the problem also exists in Media Player). I run Win2000 service pack 2, have a P3 450 and NDivia Riva TNT2 video card

If there's anyone who can give me a tip on this (which does not say "format your hard-drive" :)) please let me know

Thanx
wingcom

[DSPguru]

have you read MaTTeR's AC3 FAQs ?

[wingcom]

sorry 'bout the wrong forum thing...

I fixed it (or i got real lucky!)...
I actually did two things:
1. started reading matter's AC3 faq and somewhere in there there 's a command for registering your .ax files and so I did...
2. I lowered my postprocessing level in Powerdivx (but dunno if that helped)

Anyway, after completing these two things my playback was back to normal. I tested 3 movies and all were ok (same movies that gave me bad results for the last 2 weeks)

I dunno if it helps anybody but it seemed to help me

Greetz