mpeg2 - vob - mpeg2?

If I have some raw film footage in mpeg2 format and burn it to a dvd (which changes to vob) is there a software that to convert back to mpeg2 without rencoding causing loss of quality?

Some relevant posts:
http://forum.doom9.org/showthread.php?t=133837
http://forums.support.roxio.com/lofiversion/index.php/t9444.html
(Macs) http://forums.macrumors.com/showthread.php?t=303998

The bottom line is some DVD authoring/burning programs should have some advanced button that lets you copy the stream without re-encoding, but maybe not all. You could e-mail the makers of the program you’re using and ask them.

also you can use VideoCharge (http://www.videocharge.com/Index.php)