MPEG 2 and MPEG 4 are simply marketing gimmicks.There is nothing change in terms of PQ in these Technics.There r many MPEG2 HD Channels exists and working very fine elsewhere. so that doesnt effect /decrease the Quality. Yes MPEG4 is benefitted for adding many channels in single TP. very very latest MPEG2 Technology also available now. surely TS is updating those technology .