Why aren't small market stations upgrading to HD as quickly as they should?

[landtuna]

I guess this is a related question. I've been told that WBBJ in Jackson, TN is unable to add ME-TV as a full subchannel because of limited bandwidth and that they would have to make technical changes (Possibly new equipment?) before they can add it on another subchannel permanently. As it stands now they have:

7.1, which is ABC at 720P
7.2, which is the same programming as 7.1 except with SAP audio when its's available at 720P. I was told that this is actually the audio only, and the video is actually 7.1.
7.3, which is CBS and ME TV for filler at 480I

It seems to me that 7.2 is being wasted since it's the same programming as 7.1 only with SAP when it's available, but they're saying it's audio only. Is this true or are they making excuses? In any case it doesn't look like they're in any hurry to add ME TV as a full subchannel.

It appears they would have sufficient bandwidth, especially if they eliminated SAP. Does SAP even work on digital signals? I thought it was analog only. And, does Jackson, TN have enough second-language viewers that SAP would be used in any event?

 

[fybush]

It's not "SAP," per se. We're in a new world now.

As I understand it (and I'm sure w9wi will be along to refine my understanding any moment now), a DTV station that's multicasting is sending out multiple video and audio programs as part of its data stream, and there's a table that it sends out as part of that data stream that tells your receiver how to associate those video and audio programs with virtual channel numbers.

Each video and audio program has its own unique identifer (PID), in hexadecimal code. Looking at WBBJ on RabbitEars, here's what we see:

http://www.rabbitears.info/market.php?request=station_search&callsign=WBBJ#station (Expand the "Technical Data and Screencaps" section if it doesn't automatically open.)

Look specifically at "digital channel 43.3" (virtual 7.1) and "digital channel 43.4" (virtual 7.2) - for both of them, the video PID is 0x0031, but they have separate audio PIDs, 0x0034 for 7.1 and 0x0035 for 7.2.

What's actually taking up 13.3 mb of WBBJ's 19 mb of bandwidth is that video program 0x0031, which is common to both "7.1" and "7.2." All your receiver is doing when you switch from "7.1" to "7.2" is associating a different audio program with that same video. The separate audio programs don't take up much bandwidth at all, 384 kbps for 7.1 and 192 mbps for 7.2.

The rest of WBBJ's bandwidth is mostly taken up by the video for "7.3," which takes up 5.3 Mbps.

There is indeed very little room there to add a third video service without doing some crunching on what's already there. Getting rid of "7.2" would free up only the 192 kbps used by the "SAP" audio.

 

[AKA]

I guess I shouldn't feel too deprived: there are several markets, after all, where two or more networks are bundled onto one multicast! Though there are a few exceptions, most of those markets don't receive the "secondary" networks in HD at all.

 

[landtuna]

It's not "SAP," per se. We're in a new world now.

Excellent explanation Scott. Thanks! I didn't think SAP was used in the digital age but didn't realize the audio took so little bandwidth. I'm still interested in why a secondary audio in a place like Jackson, TN.

 

[anotherguyTN]

Thanks for the info Scott. I guess WBBJ is telling the truth. They claim the secondary audio is for Spanish. There is a growing Hispanic population in Jackson and West TN, so I guess they think it's justified. But I've heard very little Spanish on it. Most of the time it's still the main audio.

I guess WBBJ will have to cut the signal quality for 7.1 and 7.2 to make room for another subchannel and I'd guess they aren't in any hurry to do that. I don't see how 7.3 can be cut. Their biggest mistake is getting both CBS and ME TV and putting them on one subchannel. The best chance of getting ME TV Full time is probably for WJKT to pick it up and drop Cool TV, but even that may take some time. Thanks again!

 

[Kent T]

There are millions of reasons why, $$$$$ that is. All the new gear required, the installation expenses, training operators and engineers on their jobs. Small markets don't have the financial resources to do so, and even better SD used gear is usually so hammered or non supported by it's makers it is not an option.

 

[spencerkarter85]

The only small market that produces all of their news in HD is Augusta, GA. In Charleston, SC every single station doing news in HD except WCBD 2 (NBC). For those in the South Carolina Lowcountry wanted to see HD Syndicated shows, they have to watch WCIV 4 (ABC) and WCSC 5 (CBS) for the experience. Too bad for WCBD 2, WTAT 24 (FOX) since they do news in HD and also produced by WCSC despike airing FOX HD programs, and WMMP 36 (MNT) since they don't have equipment to broadcast HD syndie shows, they have to be stuck watch it in 4x3 SD instead. I felt sorry for Chucktown viewers wanted to see Wheel of Fortune and Jeopardy! in HD real bad. Here in Upstate SC, nearly every station broadcasting syndie shows in HD. I'm glad they show Wheel and J! in HD in Upstate SC.

 

[nomadcowatbk]

KRCG (CBS) is Columbia-Jefferson City does not air Ellen or ET in HD. Viewers cannot also see any syndicated shows in HD that air on the MY TV subchannel of KMIZ (ABC) or the CW+ plus feed on a subchannel of KOMU (NBC) but a lot of those syndicated stuff on those channels is not offered in HD to begin with or also available on cable