OpenShiiva does just one thing: converts VOB files to MPEG-4 format. It does this on MacOS X. VOB files are wrapped MPEG-2 format streams, such as you might find on DVDs. You can expect a nice decrease in size when going from VOB to MPEG-4, so this is ideal for archiving DVD files to your hard drive.

Version 0.8.6 is shipping as of June, 2003.

http://openshiiva.sourceforge.net/