Avi to Vob/dvd

This is what I wanna do, Convert Avi movies to vob, I have some software that will do it for me but my problem is that once converted the file is way to large to fit onto a dvd disk. A tech friend of mine said I need to reduce the frame rate or something and that I would lose some quality but that’s ok. I have no idea what I am doing. Can someone point me in the right direction?

look here.