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J. Stephen McDonald November 21st, 2017 11:35 PM

ATSC 2.0 and 3.0
 
These newer, upgraded versions of the ATSC digital TV broadcasting system are either being implemented or are soon to be so. But I'm wondering just how many broadcast stations around the U. S. are currently using ATSC 2.0?

I was checking all my local broadcast stations today, with the signal-analysis feature on my DVR. I was surprised to see that one of them (PBS) was running two channels of 1080i and one of 480i, on its 6 MHz bandwidth. I've never known before, that a station could squeeze-in more than one 1080i channel. Another station was running two 720p channels on its bandwidth. There seems to be no degradation in quality.

There are also some improved SD side-channels, from all the stations. Although using 480i, they were full widescreen and looking very sharp. One station had a 480i side channel showing an old Mayberry RFD program in color, that appeared to have an aspect of about 4.4 X 3, with narrow black sidebars. The picture quality was great and could almost have passed as HD. I'm thinking that the show was produced on film and that was used for direct encoding to digital video.

If anyone knows more about the implementation of ATSC 2.0 and the things I've discussed here, I'd appreciate being brought up to date. There isn't much on the Internet about which stations are using 2.0. My 8 year-old DVR is having no trouble recording any of the programming. From what I've read, ATSC 3.0 won't be backwardly compatible with ATSC 1.0 equipment.

Bruce Watson November 22nd, 2017 11:59 AM

Re: ATSC 2.0 and 3.0
 
Quote:

Originally Posted by J. Stephen McDonald (Post 1938841)
These newer, upgraded versions of the ATSC digital TV broadcasting system are either being implemented or are soon to be so. But I'm wondering just how many broadcast stations around the U. S. are currently using ATSC 2.0?

My understanding, flawed as it may be, is none. I don't think there is an actual ATSC 2.0. Don't think it ever got completed. It mostly was subsumed into ATSC 3.0.

Quote:

Originally Posted by J. Stephen McDonald (Post 1938841)
From what I've read, ATSC 3.0 won't be backwardly compatible with ATSC 1.0 equipment.

You wouldn't expect the 1080i / 720p H.264 CODEC of ATSC 1.0 to be able to recognize 4k / UHD H.265 bitstream, would you? So no, it's not backwards compatible. It means that old saps like me will have to buy a new TV, because my tuner is ATSC 1.0. Either that or a converter box, and I have no patience at all for a converter box. Or I could sign up for cable, but that's never going to happen again.

My understanding is that there will be an overlap period when broadcasters are broadcasting two bitstreams side-by-side (ATSC 1.0 and 3.0). That may last from 3-5 years or so. How they are going to do this after the "great repacking" (to move all the TV signals below 600 MHz because the FCC in it's infinite wisdom sold the 600-700 MHz band to cell phone providers) is beyond me. Will there be any available TV broadcast channels left unused? In major markets probably not.

J. Stephen McDonald November 22nd, 2017 03:49 PM

Re: ATSC 2.0 and 3.0
 
If there are two parallel bitstreams being transmitted, one for ATSC 1.0 and for 3.0, that would take a lot of extra bandwidth. Is the frequency range below 600 MHz available? Any converter box would have to be capable of receiving all of it. Can you imagine a converter that could receive, convert and output two channels at once and be digitally tied into an existing DVR, so programs could be time-delayed and recorded, just as the DVR did on its own before?

Nothing short of this would be acceptable to most people. It might also be opposed by manufacturers, as it would reduce the demand for expensive new 3.0 equipment. And you can imagine how ATSC 3.0 would drive up subscription rates for cable and satellite providers. With the great diminishment of expendable assets for so many people in these times, a large majority would be shut out of TV viewing, unless low-cost converters were available.

And what is the explanation of some channels now being able to squeeze two 1080i sub-channels and one 480i sub-channel into a 6 MHz channel? This couldn't be done a few years ago. Do they have some new encoding formats that are much more efficient and with lower bit-rates? I understand that with ATSC 2.0, the bit-rate can increase from 19.7 Mbps per channel with ATSC 1.0, to 25 Mbps.


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