Stevedalh,
Agreed, TVersity is really good however I find it takes a beafy machine if you are using the transcoding feature to convert videos into DSM-520 compatible format (especially for HD content) . Plus you are adding an extra decoding / encoding step which will introduce artifacts.
I will go to TVersity once I upgrade my file server, but for the time being I am trying to get the DSM-520 to play as much as possible in the files native format. If the sync problem is fixed as simply as adding something to the avi header, then I am all for that.
Now we just need to get H.264 and MKV support...