I don't know what asdl is but here's a reference with some H.264 tables.
http://en.wikipedia.org/wiki/H.264
I suppose it depends on your iptv solution, available bandwidth and stability, routing and mpeg4 level your shooting for. You want to be sure to have bandwidth headroom no matter what unless there's nothing else going on. You can end up with packets out of order. If you're trying to run the audio over a wire somwhere local along with the video over ip that's problematic. I am guessing that if you could throw mpeg 2 at say 480x480 at 4Mbps incl. audio, you might need the same bandwidth for Mpeg4 high profile, considering the better compression etc. I think Amino 125's can output that. Not sure but I thought I might post my thoughts. Myself not lucky enough to play with iptv and Mpeg4 - yet.