hello, first ive gotta say that this is an awesome forum!

ok, now onto my question. do all digital and satellite broadcasts around the world (not including xm, sirius or hdtv) encode their audio as mp2?

I know here in the UK our Freeview system uses MP2, but IIRC some exisiting television systems use MPEG4.

I know the BBC have alreay successfully trialed MPEG4 HDTV.

Even if you limit the question to radio, the answer is no.

HDTV HDFM adopted in the USA and Brazil, which has achieved small penetration so far using a different codec and a proprietary transmission system.

AAC+ will be used for DAB+, announced as an enhancement to DAB. This will allow more channels / higher quality or some tradeoff within the same bandwidth but will be incompatible with existing receivers. Presumably for higher bandwidths, AAC-LC without SBR could also be used, though I haven't seen a source for this. If AAC-LC is available I dare say that 128 kbps channels would sound very good, comparable to 192 kbps MP2.

Edit: Oops - typo. HDFM (where HD doesn't stand for anything, but it's a hybrid digital system on FM radio)