virtualdub supports ,VOB to ripp in avi

Follow these 2 steps:

1. MPEG2 plugin:copy to the 'Plugins32' folder located in the VirtualDub
folder (create the folder if it does not exist)..
http://home.comcast.net/~fcchandler/Plugins/MPEG2/index.html

2. AC3 codec:install in the system by right clicking the .inf file and
choose 'install'.
http://home.comcast.net/~fcchandler/AC3ACM/index.html

more info:http://forums.afterdawn.com/thread_view.cfm/667709