How to setup iDVD for burning pre-downloaded movie, spacewise, quality, etc

Question

I downloaded (legally) old TV shows onto my Mac, then wanted to burn them to a blank DVD for viewing thru my regular DVD player. I opened iDVD, dragging and dropping .avi files onto its start up window. Everything worked fine, iDVD automatically processed/encoded the 350 MB files, with the resulting DVDs playing the shows fine on my consumer DVD. Two questions:
1. Even though the files were only 350 MB, iDVD would not let me burn more than one file at a time onto a blank 4.7 Gb disc. Even after expanding the file during processing, the resulting new burn project was only 1.86 Gb. With 4.7 on a blank disc, why would iDVD not let me drop at least one more file for inclusion?
2. iDVD did everything automatically; there were no pop ups asking me about how I wanted it encoded on the disc, as an avi file or consumer-readable DVD, and no indicator of how big it would expand after processing or how much space it would take up. Is that normal, or shouldn't I be given choices, including write-speed/quality/compression/file size choices that might have affected how many 1-hour episodes could fit on a blank DVD?
Thanks for any clarity on this.

Answer 1

.avi is just a container, as .mov is in the Mac world... (for your interest: look in the right column, what can be inside a .mov here)
so, you're lucky, that inside that container was something, iDVD can handle, because all iApps use "dv" as codec for video (as on miniDVtapes, what iM is intended to be)
dv is a codec, which has 13Gb per hour
a dvd has mp2 as codec, which fits up to two hours on a 4.4GB dvd-r
(iDVD does the conversion..)
all iApps are not "all purpose" apps; the iLife suite is mainly for your music, web (since iLife6) and your homebrewn videos (miniDV/tape/DVD)..
if you want more options/choices, you need other tools & apps (=> $$$$); the iLife suite is for simplicity & convenience - miniDVtape, audioCD, edit, create, burn - boom!done... this is, from my p.o.v., the main difference between PC and Mac apps: PC apps overwhelm (=let him alone) with zillions of options, Mac stands for simplicity (=what PC users read as "prescribtion")
concerning file sizes:
the process of converting & generating mpegs is very tricky/elaborated.. even costly pro tools can just estimate the final project's size, because file size depends e.g. of content, amount fo movement, richness of detail, etc