its both...MPEG4 is just the way its transmitted. Normally its MPEG2
advantage of MPEG4 is they can fit more channels in a smaller transponder.
If the channel is MPEG4 it will scan in on a blind scan but on most receivers it will show under the radio portion because it cant figure out the video pid.
couple examples of MPEG4
Fashion TV on 97W KU
Saskatchewan Learning Network on 111.1 KU