vegas clips are pixelated...help?!?

[Noir X Weiss]

so..i am making an amv, and i'm using videos that are 640x480, divx codec i think. these videos were converted from h.264 .mkv to .avi using Leawo's AVI converter. i've heard that there are problems with it, but almost all of my clips have no problem, except the clips that are from one of my videos. there is minor pixelation (only in some areas) after rendering in .wmv, 640x480, and 60fps. can anyone help? also i noticed that this only happened after some point with Leawo (i converted a few videos that worked, then after one of them, they would be pixelated in vegas, if that makes sense). will reconverting fix this? and is there any way i can do it without losing my work?

[Nya-chan Production]

Read this: http://www.animemusicvideos.org/guides/avtech31/

Mainly the section about lossless codecs ;x

[Noir X Weiss]

thanks! this helped me meet the deadline for my AMV!