I trim a lot of Divx and Xvid avi's using Virtual Dub, as well as Easy Video Splitter (which I then convert to DVD ready mpgs using TMPGEnc). But, I got a few Divx movies with ogg vorbis audio which I can play just fine, but when I trim, I lose sound completely. Is there a workaround? I also have a Mac.
ogg vorbis in an avi is a bad idea. Aside from sticking a container (ogg) in a nother container (avi), avi simply can't handle it properly. I would suggest that you convert it to something else before trying to do anything with it.