gmclam said:
Just to get the audio from ATSC is no small task. First you have to demodulate the 8VSB signal. Then you have to parse the transport stream. And there are several channels of audio. Depending on settings, some may need to be mixed as they are sent 5.1 or stereo and with sub channels of stuff.
What he said.
There isn't enough of a market for such a device. Scanners aren't marketed to specifically receive broadcast audio - they do so because they are devices that demodulate radio signals, and the audio carriers of TV stations are just that - separate audio signals transmitted separatley from the video signal.
As with what gmclam said, the audio and video signal with ATSC are multiplexed into a single MPEG2 transport stream on a single RF carrier..... in other words, it's a big long string of ones and zeros that carry both the audio and video signals together. In traditional NTSC broadcasting, the audio and video carriers are transmitted as two totally separate signals, which means you can listen to the TV audio without the BZZZZZZZZZZT of the video signal interfereing.
So... will this mean that there will be scanners that will decode audio from ATSC signals? Absolutley definitley positivley 100% NO. As it was mentioned, it takes quite a bit of processor power not only to decode the packets in the transport stream, but also to decode whatever audio codec ATSC uses (some sort of Dolby codec I think, I know that ATSC will be capable of Dolby 5.1, and not too many scanners are capable of that). No scanner manufacuturer would spend that kind of scratch in developing, creating and marketing such a beast of a scanner so only a few people will be able to listen to TV audio.
Will scanners capable of listening to HD Radio exist? Of course - they're called Walkmans (or whatever kind of personal stereo is currently marketed/to be marketed in the future that will recieve HD Radio).