Record the whole mux, open it up in a text editor, inspect manually. I caught some http requests and URLs that way. I suppose it doesn't absolutely prove the 33 and 34 PIDs are internet data, though, since I didn't take the time to isolate them, but there certainly is an internet component in there. I wouldn't have presumed internet and other (video?) data be mixed on the same transponder, but it's possible.
I do suspect a proprietary encoding as well, if my presumption of all internet data is correct.