The problem with all the HDTV systems I know of is that the audio is encapsulated in a transport stream, in the case of 8VSB (US HDTV) running at close to 20 Mbps. You have to receive the entire bitstream, and demux the content you want, and at that point, you might as well watch the video PID too.
The other thing to keep in mind is there are very few lowband VHF TV stations. Most migrated to UHF and a few on highband VHF. Lowband has trouble with impulse noise which can cause breakup/tiling.
+-RH