Converting variable framerate wmv to avi without losing sync.

[DK-II]

I have spent many days trying to convert a wmv file to avi (xvid) without losing av sync but haven't had any luck so far. I've tried a number of programs in various ways and always end up with av out of sync. I've used TMPGEnc Xpress 3.0, Stoik Video Converter, VirtualDub 1.3c, SUPER, Windows Media Encoder 9, ASF Tools & Graph Edit. I have tried to follow the instructions of quite a few guides on this website as well as others without any success. I can't get VD 1.3c to open the wmv file (or many other wmv files I've tried) as I keep geting an error message saying "ASF: illegal object fragment flags 0a in packet at 13ba packet size = 1f40, pp = 13 send time: 0:00" or a variant of that. WME 7.1 seems to be unavailable these days (apparently it's compatible with ASF Tools but version 9 isn't). Stoik can only convert to simple profile xvid which isn't good enough for me. I've tried numerous methods to make the wmv constant framerate without any success. The main problem seems to be the wmv file's framerate isn't constant. If I could convert it to a constant framerate wmv with av in sync I would probably have no problems converting that to an avi which was also in sync.

Here's the file info:
File size : 135 MiB
Format : Windows Media
Overal BitRate : 692 KBps
PlayTime : 27mn 14s

Video #0
Codec : WMV1
Width : 400
Height : 300
Aspect ratio : 4/3

Audio #0
Codec : WMA2
Bit rate : 64 KBps
Channels : 2 channels
Sampling rate : 44 KHz

Any help in converting this file to avi in sync would be great. There's a good chance people will recommend trying things I've already tried coz I've tried so many different things but hopefully someone can tell me something new. It would take too long to mention all the different methods I've tried and I'm not sure I can remember all of them.
Thanks in advance.

[Nelson37]

Chop it into segments to isolate the framerate changes?

Save the audio as a Wav file and convert audio and video seperately?

Just say "tellwiddit" and have a beer, meanwhile soundly cursing the dumb SOB who created this POS?

[DK-II]

Chop it into segments to isolate the framerate changes?

This would be too time consuming and I have no idea when the framerate changes occur nor what the framerate is at any given time.

Save the audio as a Wav file and convert audio and video seperately?

I don't see how this will help because I'm sure it's the video that's causing the problem, not the audio. The input framerate will still be variable so the output av will still be out of sync.

Just say "tellwiddit" and have a beer, meanwhile soundly cursing the dumb SOB who created this POS?

I don't drink but I'm definitely cursing the dumb SOB. I'm not giving up after spending this much time on it though as I'm sure other files will give me the same problem in the future and I don't want to delete all of them.