Fast alternative to iDVD for converting AVI to DVD video?

I have used iDVD to convert an AVI file into a DVD video. The result was very bad. The AVI file was 700MB. It took 2 hours 35 minutes to encode, then another 20 or so minutes to burn. That's a total of about 3 hours. But the worst thing is that the quality of the DVD is terrible! The resolution is really bad and I can see all the little squares. The original AVI file was much better quality.

I can't make sense of that. Surely there should be no loss of quality from 700MB expanded to a whole DVD? Does anyone know a better program for this job, which will keep the original quality and hopefully be a bit faster?!

Thank you!
Justin

G'day Justin. Do you need the file to be in DVD format, like are you gonna just watch it on your mac or do you need to be able to burn it to disc to watch on a standalone DVD player?

Standalone DVD player. Very happy to hear suggestions! One program I have seen is Visualhub. Have you tried that? Any better? (Have to pay for it).
Thanks
Justin

I have ffmpegX and you can convert the avi into DVD format using that (for free).