Actually VLC doesn't provide information if stream is audio or video. But I have the same problem with my provider which sends udp streams. And I think that I don't convince my provider to change it's streams. In the MP 1.1.3 (SVN tags 1.1.2) it works.If you are using VLC to stream these channels then I suggest that you contact the VLC developers and ask them to fix this issue rather than adding the change to MediaPortal.
I accept that I'm comming with new filter to late and probably will not be included with MP 1.2.0. I think that this thread can be closed and we can continue in discussion on new thread for MP 1.2.0 Beta (https://forum.team-mediaportal.com/mediaportal-1-2-0-beta-540/tvserver-while-scanning-doesnt-add-new-iptv-channels-95882/), because MP 1.2.0 Alpha is obsolete.[Edit: TV Server is meant to be compatible with the existing filter. The new filter may be very desirable for its new features, however until the updated filter is added to TV Server I think it is a little unfair to say that it is our bug.]