DVDs are MPEGs not AVIs If you have the DVD structure (.ifos and .vobs) in a folder there is no need to convert. In cases like that I would grab DVDShrink write the whole DVD structure to an ISO image (~10minutes) which then I burn to DVD with Burnaware free. But nowadays every burn program can handle ISO images.
If you want to convert AVI MKV OGG WMP FLV and what else there is, that's a lil more complicated.
If your DVD player has build in codecs, then you can burn the clips simply as data.
If not you have to convert everything into a DVD structure first, create a menu and go from there. I used to do that with DVDLab Pro (that's not free but supports multiple soundtracks) a 30 day trial you can get from HERE. If you don't need all the extra features you might want to look into WinDVD Creator Platinum another 30day trial.

If it's about free programs you might want to check out DVD Flick and DVD Styler

-DG