Chyba tu cos jest:
http://abmefaq.net/Join.html#WMV
na dole...
FOR WMV(A)
MyAsfTools - currently version 2.3. Can join, edit, split, and
repair ASF and WMV files. Still a long way to go, but this is way ahead of the others. Join, split, minor edits allowed. I've dropped most of the other tools I've used with asf and wmv1, and replaced them with this one. Output as an uncompressed AVI.
...coś takiego jest napisane.