Parsing (read. decoding) ASF files is illegal as only Microsoft or licensed (read none) products can do it. There are some obscure apps out there that can do it, but all that devs I know of have been 'contacted' by Microsoft to discourage further development or even acknowledgment.
This has something to do with security by obscurity as well as built-in DRM stuff, plus some good ol Microsoft aberrant behaviour thrown in.
AFAIK, licensed programs can *generate* ASF files (read, Media Cleaner and others) but not read them. How people put up with this amount of crap doesn't cease to amaze me.
dani++