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What is sensible programming for ATSC sub-channels?

10K views 47 replies 15 participants last post by  alebowgm 
#1 ·
Just curious as to what other DHCer's thoughts were on this as I've had a few thoughts myself while wondering why WUTV (Fox 14/29 Buffalo) mulitcasts (generally) the same content on 29.2 in SD, as what is being shown 29.1 HD.
[I know the last few days when I've checked 29.2 it has just been black - an even greater waste.]
My thought is there is no value to repeating in SD unless you have a 4:3 tv and are still able to stretch the image to eliminate any pillar/letterbox, whatever.... I've never seen a 4:3 tv with this capablilty, and why would I look for one :rolleyes: Do all ATSC tuners down-convert for those displays incapable of displaying 780p/1080i? - I certainly don't know, but I would think so.

I am not talking about PQ here. I think it is agreed that PQ suffers when anything less than 19.4 Mbs.
I am not talking about network/station ad revenues. That has been discussed.
I am not talking about putting NewsWorld on 5.2/20.2. Same reason.

What I am talking about is if the broadcaster insists on chopping the quality on their main HD feed, for what ever corporate reasons they want, why bother with a concurrent SD or Radar? I know due to it's static nature, Radar probably doesn't chew up a lot of bandwith, but am I in the minority to say I have spent an entire 12 seconds watching it?

One idea I had would be to repeat an earlier program in SD (I don't have a PVR), but I'm sure they've already thought of that..
 
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#2 ·
You've raised a point that I think is broadcast policy that is basically for each station to decide. Some stations prefer to give top notch ATSC quality (such as CBC-HD) while others try to split their signals to the max, all the while ruining HD quality.

My suggestion is to determine who the worst offenders are in your part of Canada and then contact them to complain.
 
#4 ·
You've raised a point that I think is broadcast policy that is basically for each station to decide.
The FCC might allow the bandwidth given to each station to be used for other purposes. I have read that subchannels might be even allowed as revenue generating venues, such as infommercials etc. Weather channels and radar are just the tip of the iceberg of services that a station might put forward. Why, I actually watched a program on Think Bright (43-3) the other day.:D
 
#3 ·
I personally dont mind having some sub channels, as long as there is not a NOTICEABLE difference in the HDTV quality, and the content that we are getting is worth it. WNGS on 7-2 is worth it, but Radar on 4-2/23-2 is nice to have but nothing special.

I actually think that CityTV should add a multicast of A-Channel Barrie, being that they cross promote and CKVR has some compelling content. I also feel that CBC should multicast when there are hockey games that are split across the market, so you can watch the Leaf game in HD on 5-1 but on the subs have the other games.

In regards to Sinclair and Fox, it wouldn't surprise me if 'The Tube' launches up as Sinclair has an agreement with that station to air on their digital subchannels its content, and has done so in many markets yet supprisngly not on Fox (or even WB)
 
#7 ·
I've suggested to CHNM-DT (Channel-M) to use subchannels once they get DTV ready, as they don't have HD content, and have newscasts in several languages. At typical news time, they could play 4 or 5 of their newscasts on separate subchannels. After the typical newshour timeslot, they could loop the most popular non-english language newscasts on .2, .3, .4 subchannels while regular programming would be on the .1 subchannel.

I'd consider that sensible. And if you're Mandarin speaking and would normally miss the Mandarin newscast, you can catch it at a later time or watch it earlier, at say 6pm when English language newscasts are on other channels.

Where this would cease to be sensible is when they play HD content on their main feed, as the subs would be taking bandwidth away from the HD feed.
 
#8 ·
Are there any Canadian TV stations that use sub-channels? I was under the impression that the CRTC is insisting that the stations use all of their bandwidth to provide the best HD picture possible.

I don't think this is permitted, but I think it would be great if stations could dynamically add and remove sub-channels so that if they are broadcasting in HD they remove the sub-channels to maximize bandwidth, but if the program is in SD, they can add additional sub-channels to provide variety in their programming.
 
#9 ·
no WNED's quality, and Yamoon can confirm, is being compressed by PBS at the source of the signal that is being uplinked for all the local PBS affiiliates. I believe he pulled in the Rochester PBS and even called WNED to ask, and that was what he was told. The sub's are not affecting it...

The reason I suggested A-Channel and not CP24, although I do think CP24 is very compelling content, is that CKVR is an OTA station where as CP24 is a Cable Station. Figure had more chance with an OTA station cause people don't have to have a speciality sub for that station.

In regards to the CRTC, that actually may make sense with why there is no digital sub channels. I was talking to CKVR about DTV broadcasts and if it was even a blip on their radar, and aside from saying NO (they are waiting to see who becomes their new owners now that Chum bas been purchased by CTV and they have said they want to sell A-Channel stations), he said the CRTC may have some sort of leagl opposition to CITY-DT multicasting CKVR.

It’s unlikely that we’ll see a great deal happening on the DTV front until the CHUM sale to BGM is finalized and A-Channel’s new owner is secured.

Regarding your comments, our VHF assignment does have some advantages… lower electrical bills since the power output is much lower than UHF to get the same coverage.

City is transmitting in HD so there wouldn’t be enough bandwidth to multicast plus I’m not sure the CRTC would allow City to carry Barrie programming at this time.

Thanks for your interest.
 
#10 ·
how could we find out if The Tube music video channel will be coming to Buffalo?

or is there a way to leave comments to encourage them to bring it in? I've seen some of that channel on DXing nights from Rochester, it is seems like quite a decent channel to be able to recieve.
 
#11 ·
WIVB 39/4 just put an interesting twist on multicasting. Sub .2 was a doppler radar channel, which has now been replaced with a close-up static sat view of Buffalo hybrid with major roads. I would assume this would be used for traffic reports.
..... useful I guess if you can point a silver sensor out your car window while stuck on the Peace Bridge.

Ooops, now I look up and since I starting typing this post, radar is back !
 
#13 ·
noticed it again while surfing

Radar briefly switched to this again. Back to normal since I loaded the pic.
This image is zoomed out somewhat from what I saw last week, which was zoomed in on central Buffalo.
I think that is what this really is just Radar zoomed in, since the graphic overlay is similar in format to Radar. But the idea of a traffic sub made think (for a second).
 
#16 ·
They could alternate between radar and traffic every 5 or 10 seconds. If they timed the switch with a screen redraw frame it wouldn't take any more bandwidth than displaying only one or the other.
 
#19 ·
The problem with WNED isn't 2 SDTV channels, it's 2 EDTV sub channels. EDTV (852x480) has approximately 1/3rd more pixels than SDTV (640x480). So WNED is effectively carrying 2 and 2/3rds SDTV channels worth of video in the sub channels.

Actually, there is a much better way to do things. There's almost 2/3rd of a century of SDTV shows lying around. There are networks like RTN that show them, not to mention PBS. After the analog shutdown, 3 or 4 SDTV-resolution stations could share one DTV transmitter. It would be a lot less wasteful than using 6 mhz for one SDTV signal. On the economic side, splitting the cost of the transmitter 3 or 4 ways is economically attractive.
 
#20 ·
Walter Dnes said:
On the economic side, splitting the cost of the transmitter 3 or 4 ways is economically attractive.
Especially if after the the analog shutdown, one or two transmitters in every market were permitted to transition to shared SDTV transmitters. Much of the infrastructure would already be there and it would just be a matter of replacing the analog equipment with digital equipment.
 
#21 ·
The argument I've heard against pooling several different or competing stations into one channel's sub-channels is the "all the eggs in one basket" problem, in which several different broadcasters have their signals going to just one transmitter/tower. Some stations would not be comfortable with that, because a set of technical problems could take them all down at once. Companies would have to weigh out the economic and technical benefits/risks.
 
#22 ·
The argument I've heard against pooling several different or competing stations into one channel's sub-channels is the "all the eggs in one basket" problem, in which several different broadcasters have their signals going to just one transmitter/tower. Some stations would not be comfortable with that, because a set of technical problems could take them all down at once.
I don't understand that argument. Why is the shared transmitter likely to be less reliable than one you own outright? Besides, if your station goes off the air, do you really care that your competitors go off too?

I'm reading between the lines here, so correct me if I'm wrong. Are you suggesting that the combined ownership will cheap out on maintenance versus a single-channel-owned transmitter? Think of the condominium model, applied to TV transmitters.

Besides, if I was Industry Canada or the FCC, I would look very unfavourably at the concept of wasting 3/4 of the capacity of a DTV channel to broadcast one SDTV-only signal. 4 SDTV "stations" teaming up to use one DTV channel would be more reasonable.
 
#23 ·
Maybe some correspondence with stations would help you get answers to your questions, I'd be curious to see what they have to say on this topic. I don't speak for them - I just relayed an argument I'd heard in relation to shared sub-channel transmitters.

Rather than speak for them, I'm just going to say that in my opinion broadcasters need to be on the air to make money so if a technical glitch forces several competing stations off the air, the economic hit is that much wider than if only one competitor's station goes down.

Also, in times of emergency it would be best if stations were not all subject to technical problems at one site. If there is a chance that one or more of them can take to the air, that is preferable and logical to me.
 
#24 ·
rebranding of existing stations as subs.

Multiple stations multicasting on the same frequency might make economic sense in terms of bandwidth efficiency. However, different stations multicasting on the same frequency would run into branding issues. What existing station would want to have to re-market themselves as Channel X.2 (or .3 or .4) of their competitors? Every unique SD station would want to be the highly visible .1 designation.

Where network stations are co-owned or otherwise aligned it might make sense. However, I can't think of any Canadian subsidiary station that should be a sub of a non-HD station. I don't like the idea of SD subs sharing a channel allotment with an existing HD channel.

Perhaps new stations might accept a .2 or .3 channel designation if they were given license allowances (monetary incentives?) from the CRTC.
 
#26 ·
But PSIP remapping would allow existing channel brands to show up (i.e. 27.1 remaps to 8, 27.2 remaps to 3, 27.3 remaps to 10)
Is it possible to map different sub channels to different channel numbers? I would have thought this would be done in the US where two analog channels share a digital channel if it was possible.
 
#28 ·
Well, the PSIP documentation (A69/Annex B) says that in the U.S. all Digital OTA major numbers must correspond with the station's NTSC channel number. I interpret that to mean that an NTSC station on Channel 8 that is on Channel 36 digitally is not going to be able to assign 36.x sub-channels to other NTSC stations in the market. I'll keep reading to see if its any clearer.
 
#29 ·
stampeder said:
in the U.S. all Digital OTA major numbers must correspond with the station's NTSC channel number.
I susspect this rule was created with the assumption that all stations would revert to their NTSC channel number after the analog shutdown to ensure that no two channels in a given market would have the same virtual channel number. This rule has probably been changed to permit stations to now use the physical channel number that they will use after the analog shutdown (I think some stations have started to do this) and require them to use this number after the analog shutdown.
 
#30 ·
Originally Posted by stampeder
so is that what you meant
Sorry, as roger1818 suggested no. You are correct in pointing out that I erronously made an assumption that subs could only remap to the same channel designation as the major channel. Although that might actually be the case, it was an assumption, and should be considered that until we dig up the goods on atsc.org. I made it considering all the confusion in 2006 summer with the realignment of the Buffalo networks and the transmission site changing hands. I can't remember for sure, by I think WNLO was subbing on WNYO, or did I mess that up too :confused: ?
Regardless, the likelyhood of this is apparently nil in the US because of:
Originally Posted by stampeder
...in the U.S. all Digital OTA major numbers must correspond with the station's NTSC channel number.
These are rules created for the US. Would Canada carbon copy the US policy?

Originally Posted by roger1818
I susspect this rule was created with the assumption that all stations would revert to their NTSC channel number after the analog shutdown to ensure that no two channels in a given market would have the same virtual channel number....
WUTV-DT (FOX) applied to revert to 29 after analog shutdown and was denied - they must stay on 14.

With respect to the content of my post:
Every unique SD station would want to be the highly visible .1 designation.
I was basing that on if subs cannot remap to a different major number. The Samsung T-451 tuner for example goes directly to the .1 sub if you enter a channel number directly entering using the number buttons, as opposed to surfing up/down to it. You cannot enter the subchannel designation.
for example:
If I'm on channel 5, and press [4] [3] [enter], it will take me to 43.1, even though 43.2 and 43.3 are valid. In fact to get to 43.3 directly, I would have to enter [4] [3] [enter], and then surf to 43.3 through 43.2.​
To me, that means 43.1 gets a higher hit count.
confused yet?... I know I am ;)
 
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