Just check the specs for any conversion program (especially if you are buying it). As everyone knows, I have a 1.7 gig XP system with 1 gig of ram and it struggles with many newer programs.
I personally use Ultra MP4 video converter from aone-soft (bought before I realized just how much free stuff was out there though :-[ ) - it's around $30 but with free lifetime upgrades and tech support. Notwithstanding the name, it converts pretty well anything to everything including video soundtracks to mp3 etc so I generally still use it.
They were very nice in emails as well when I got stuck with mov files (unusual these days)
Super is great but takes years on my PC now.
Then again, I don't have anything hi-tech to play stuff on

I've also not tried converting to DVD with it so can't comment on the sync.
I'll have a play around with XBMC (as it's free). I like new toys
EDIT
Wah. New toy not play

Just goes to a black screen and a Microsoft box comes up saying it's encountered an error and has to close.
Oh well, old PC
Also tried an earlier version of XBMC and still no joy, Apparently my graphic chip (S3 ProsavageDDR) doesn't support this OpenGL and there are no driver updates available (box says MS OpenGL detected, please get latest OpenGL from your card vendor).
Must look for an even earlier version of XBMC. Got the bit between my teeth now
