Okay, got TMPGenc to work, etc., etc. No problem vurnings VCDs, SVCDs, so time to move on to using VirtualDub.
Downloaded VirtualDub and installed the extension DLL. All well and good.
BUT...when I try to open a source AVI file to process with VirtualDub, I get the weird error message:

NO VIDEO SOURCE

Mind you, these AVI files play perfectly well with the Microsoft Media Player as well as with the Ulead Video Studio codec, and various other video codecs. So the problem is unlikely to be the AVI file.
Yes, I have installed the latest greatest version of Microsoft Direct X 8.1 as well as the updated Direct X 8.0 capture patches. Everything workds fine, Direct X 8.1 appears to be installed and running smoothly.
Incidentally I capture the AVI files from a camcorder through a firewire card. I know better than to try to use VirtualDub to capture the video, that won't work -- but from what Avery Lee has written in his docs, VirtualDub _should_ be able to open the AVI file _after_ it has been captured by another program.
Alas, no go. VirtualDub absolutely positively refuses to open my AVI files. It will open my MPEG-1 files created with TMPGenc, however.
--xed