DamnFineOnline
you need to d/l the divx codec.
http://www.divx.com/
and yes you can batch with VDub. When you click "save as avi"
the dialog box will pop up, lower left corner check
"add operation to job list and defer processing"
the F4 key will let you access the job list.
the docs are at
http://www.virtualdub.org