I have a problem with some Divx4 and Xvid videos. When I view the videos directly on WMP, it looks fine but when I use AVS script and view it on WMP, it has green artifacts and pixelation. What can i do to fix this problem? I tried using ffdshow to decode the videos but problem is still the same.

Wich avs version ? And what is in your script ?

AVIsynth 2.5
AVIsource(C:\ABC.avi)

I tried in YV12 and YUY2.

And did you tried with other than wmp ?
Can you put your avs in gspot ? I don't remember the name of the codec used by windows to display an avs output.

I think I've found the problem. I tried it in Media Player Classic and the filter it was using is "AVI Decompressor YV12". It's not using the decoders reported by GSPOT. I think all I have to do is reinstall the codecs and restart. Thanks.

I was wrong. The filter "AVI Decompressor" is used only all my AVS script according to Media Player Classic, so I guess the filter belongs to AVIsynth. I still managed to solve the problem by using Directshowsource() instead of AVIsource(). Is directshowsource() what I should be using for my AVI videos because all filters like Divx, Xvid, etc are directshow filters, so it kinna make sense.

When I view either the AVI or the AVS script in VirtualDub, the green artifacts appears. Apparently Virtualdub works like AVISource().

You are using a bad workaround insteed of trying to fix the problem

Reinstall the codecs by hand (not with a codec pack) using the last Nic's release for Xvid and the 5.1.1 for Divx. And REMOVE ALL OTHER VERSION that are on your disc. Remove also ffdshow as the last version are really bugged (even if I didn't try the latest one, with ffvfw included, I guess it is bugged as all version are since june 2003 but they weren't before).
Last step : configure boith Divx AND Xvid to not make any postprocessing and to output as YV12 (called "enhanced YV mode" in Divx5.1.1)

OK I'll try this method when directshowsource() fails next time but why do you say directshowsource is a bad workaround? It DID solve the green artifact problem.

Because this introduces a lot of other potentials problems !

See my post here :
http://www.kvcd.net/forum/viewtopic.php?t=9510

Can you instruct us newbies on how to do that? Thanks.