I agree completely with Tijl. As a matter of fact, with the new mplayer deinterlacers, I find I can rip a dvd to mpeg4 and then convert it back to a dvd and have it look BETTER than the original when the original was the result of several improperly executed deint/reint steps ;^)
Also, if you can successfully OCR subtitles you can fix spelling, grammar, and translation errors. For me, commercial dvd's are just badly formatted raws that are unsuitable for viewing ;^) See this page for my current dvd-ripping settings (often updated): http://inferno.slug.org/cgi-bin/wiki?DvdToAvi Note that subrip currently has a bug where it always quits before OCR'ing the full set of subs. There does not seem to be any way to fool it into finishing. I hope to have some time to look into this problem this summer, but hopefully somebody who already understands how it works will go in and fix it sooner ;^) I apologise for using mencoder for ripping, I use transcode primarily for re-encoding to dvd, where it excels due to it's excellent geometry management automation.
