Never - Cost of converting ALL STB's makes this a non-starter. Not to mention that at the bitrates DBS is using, MPEG2 and MPEG4 are essentially equal.
What DOES hold promise is to convert from the current QPSK to 8PSK, similar to what Dish is doing for Discovery HD Theater. This will add about 30% more bandwidth (by the time error correction is factored in). But again, this will take a systemwide replacement of all IRD's.
What DOES hold promise is to convert from the current QPSK to 8PSK, similar to what Dish is doing for Discovery HD Theater. This will add about 30% more bandwidth (by the time error correction is factored in). But again, this will take a systemwide replacement of all IRD's.