Quick notes about ripping DVDs in 4 commands based on mencoder.

Mencoder supports more formats than transcode.

DVD=PATH_TO_DVD
cat ${DVD}/VIDEO_TS/VTS_01_*.VOB | mencoder -ovc frameno -o frameno.avi -oac lavc -lavcopts acodec=vorbis -alang en -

The first pass generates file divx1pass.log (and uses frameno.avi).

VBITRATE=1060
mencoder -oac copy -vf scale -zoom -xy 512 -o /dev/null -ovc lavc -lavcopts vbitrate=${VBITRATE}:vhq:vpass=1 -ss 1:00 -endpos 1:30 ${DVD}/VIDEO_TS/VTS_01_1.VOB

The second one generates file divx2pass.log (and uses frameno.avi).

OUTPUT=OUTPUT.avi
mencoder -oac copy -vf scale -zoom -xy 512 -o ${OUTPUT} -ovc lavc -lavcopts vbitrate=${VBITRATE}:vhq:vpass=2 -ss 1:00 -endpos 1:30 ${DVD}/VIDEO_TS/VTS_01_1.VOB

Once the preview is satisfactory, the same can be done with the full DVD.

cat ${DVD}/VIDEO_TS/VTS_01_*.VOB | mencoder -oac copy -vf scale -zoom -xy 512 -o /dev/null -ovc lavc -lavcopts vbitrate=${VBITRATE}:vhq:vpass=1 -
cat ${DVD}/VIDEO_TS/VTS_01_*.VOB | mencoder -oac copy -vf scale -zoom -xy 512 -o ${OUTPUT} -ovc lavc -lavcopts vbitrate=${VBITRATE}:vhq:vpass=2 -

The default video format is MPEG4. To use e.g., Theora, vcodec=libtheora can be added to -lavcopts.