Type of media file and its metadata

Hi all,

appologies in advance if you have discussed this before ... but have we
decided how our API should "find out" the type of a media file? That
information is important for knowing what metadata  to expect. Not all
formats we are discussing have a mime type registered. And a URI like
http://gdata.youtube.com/feeds/api/videos? gives you the content-type
application/atom+xml , but within the Atom feed there are many formats being
used. Should we allow the API to do content sniffing to find out what is
available?

Felix