Bob Miller wrote: > Do what you will with receivers. You can't make legacy > recievers work with MPEG4 and when you come to the point > that you want to dump all current receivers to implement > a better codec it only makes sense to switch to the best > modulation also. Honestly, there's some sort of brick wall here that I can't fathom. You and Craig make this same point, and I can't tell if you're referring to personalities at the ATSC, or if you are missing the concept of layered protocols. When European DVB-T moves to HDTV, it is mandating that this incompatible HD stream be sent using AVC compression. They are NOT at the same time mandating a change to DVB-T2 or to DMBT. There's absolutely no need to change the physical layer just because you want to add something at the application layer. And also, they are mandating that SDTV remain at MPEG-2 compression, so as not to obsolete all existing receivers. In the US and in Australia, HDTV already exists. So there's no pressing need to add HDTV, and no immediate opportunity to introduce AVC. But AVC *could* be introduced just as "easily" as it is being in France and in the UK. > At the moment broadcasters are contemplating going with a > mobile variant of 8-VSB that could use most of the 6 MHz > channel and I would think they would use MPEG4. While > technically and legally OK it is not in the spirit of > maintaining compatibility with legacy receivers. The mobile stream could use far less than half the capacity of the 6 MHz band, leaving the rest to existing 8T-VSB television. Obviously, if the mobile stream were to require an entire 6 MHz channel, you'd consider moving it elsewhere perhaps, and then could use a different modulation. Whatever the case may be, as of now, the FCC requires a TV broadcaster using the TV spectrum to transmit at least one SDTV stream as MPEG-2 over 8T-VSB. This is very much in line with what is being done in Europe with HDTV introduction. Over there, SD streams using MPEG-2 are to be retained as well. So again, I just don't understand the disconnect. You and Craig are creating differences that simply don't exist. Everyone has exactly the same problem with legacy. Lucky for us, we ALREADY have HDTV. And no need to simulcast HDTV, either. That's good, not bad. As to mobile, my personal preference is to focus on making 8T-VSB receivers better for mobility, with better training, blind equalization, and diversity antenna, rather than creating the new narrow stream. But that's just me. Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.