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Discussion Starter · #1 ·
Why do some stations that broadcast in HD, have a SD subchannel that simply duplicates the content of the main (HD) subchannel, downrezzed to SD of course? It seems utterly redundant to me, and of course degrades the PQ of the HD subchannel.


Fortunately not many stations around here do it. In fact, in recent weeks two of them discontinued their SD simulcast subchannels. However, I just discovered that another station that didn't do it before, has recently started to do it! Grrr...
 

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That's what our CBS does. Apparently there were some interference issues getting the analog feed via channel 3 OTA so they SD simulcast and the local cablecos can get the SD feed off the subchannel instead. Of course that screws up the HD feed drastically (for WBTV anyway)
 

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What would they do come 2009 for SD viewers for the stations that don't have these? Letterboxing the HD channel is an option, but then you would get windowboxing every time something 4:3 came on the screen, and it's not like everything will be 16:9 by then either. If they center-cut the HD feed, it could cut off people/graphics in shows framed for 16:9. Do the networks have plans as to what they're going to do after the analog shut-off?
 

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Ours replaced The Tube with the SD simulcast-they stated contract termination. The HD feed(albeit mostly at prime time as it's a national feed) continues. Tonight the guide indicates alternate programing but they're both Armed and Famous. Some cableco may need an SD feed, but others are analog (ABC,NBC) and don't broadcast an SD feed( yeah PBS). I hope they find better use for "our" bandwith.
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by CPanther95 /forum/post/0


That's what our CBS does. Apparently there were some interference issues getting the analog feed via channel 3 OTA so they SD simulcast and the local cablecos can get the SD feed off the subchannel instead. Of course that screws up the HD feed drastically (for WBTV anyway)

But WBTV stopped doing it around New Year! They even dropped their 24/7 weather radar, too, so now they have just the HD subchannel on 3.1.
 

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Quote:
Originally Posted by SJKurtzke /forum/post/0


What would they do come 2009 for SD viewers for the stations that don't have these? Letterboxing the HD channel is an option, but then you would get windowboxing every time something 4:3 came on the screen, and it's not like everything will be 16:9 by then either. If they center-cut the HD feed, it could cut off people/graphics in shows framed for 16:9. Do the networks have plans as to what they're going to do after the analog shut-off?
Active Format Description (AFD). The system is already in use in Europe for SD 16:9.
 

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Quote:
Originally Posted by jtbell /forum/post/0


and of course degrades the PQ of the HD subchannel.

! Grrr...

Not necessarily. With high-efficiency encoders and proper multiplex setup,

it can be done very well. Especially if the network is 720p. (FYI, WOLO-DT is 14mb/s)
 

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Widescreen Review's Greg Rogers queried CBS station engineer Lee Wood on this topic (dupe digital SD broadcasts) for the July 2001 issue. Wood's reply:
Quote:
The main reason is that many viewers have 4:3 screens. They will letterbox the 16:9 HDTV on their 4:3 screens, but we run the standard definition 4:3 so if they want a full screen picture they will get it... So we continue to run a 4:3 program for both standard- and high-definition sets that have a 4:3 screen ratio. There's quite a few out there.

No doubt there are fewer 4:3 HD sets sold 6 years latter, but this reasoning might still apply with some stations. The don't-want-no-stinking-black-bars crowd can get quite nasty to station managers.


Recall posting about it way back because someone watching a movie at Wood's station was complaining here about breakups in a CBS-delivered movie (river rapids) that I wasn't seeing receiving more of the full 17-Mbps video payload . - John
 

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Back to the original topic- beyond the fact that it might be better for feeding cable or DBS (there's post someplace that one of the boston SD locals on Directv is fed by an SD ATSC feed)- I think there is also a bit of "place holding" They dont have a need for the subchannel right yet but want to use it for whatever reason- the example above would be the station that dropped the tube and then put an SD feed in it's space. Also the Philly ABC had their weather radar with NOAA weather radio up as a sub-channel for a long time until they put up a "real" sub channel.


Maybe they want to get used to running 2 channels. Maybe they want the HD viewers to be used to the 14-15 mb/s PQ. Maybe they use it as a negotiating point for retransmission consent. Not sure why but it seems to be some just want a place holder.
 

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Quote:
Originally Posted by jtbell /forum/post/0


But WBTV stopped doing it around New Year! They even dropped their 24/7 weather radar, too, so now they have just the HD subchannel on 3.1.

I haven't checked 3-2 lately (SD feed to cable), but I know they dropped the 3-3 weather subchannel because they couldn't (or didn't want to) meet the FCC's Kid Vid requirements. Unfortunately, reports are that the bandwidth was never added back to the HD feed - it just remains unused. Not sure whether that's the case with 3-2 if it is no longer in use.
 

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CPanther95 said:
I Unfortunately, reports are that the bandwidth was never added back to the HD feed -
Last time I looked, it had been given back to the HD..
 

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My CBS and NBC affiliates' SD simulcasts are completely mysterious. The CBS station has an excellent SD simulcast, clearly better than their NTSC channel and plenty good enough to pipe into a cable system, except they turn it off during sports so the HD channel will look good. Since cable viewers probably want to watch football games, the cable company can't be relying on this as the station's feed.


The NBC station has their SD simulcast on all the time. Thanks to them carrying Weather Plus, their NBC SD channel is a scrambled bit-starved laughable mess not even suitable for watching on an iPod:




It regularly pauses, puts out one recognizable picture followed by some jumpy splattered motion, then pauses again. Clearly they're not sending this to any cable system.


So I can find no value to either of these SD simulcasts.
 

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Quote:
Originally Posted by John Mason /forum/post/0


No doubt there are fewer 4:3 HD sets sold 6 years latter, but this reasoning might still apply with some stations. The don't-want-no-stinking-black-bars crowd can get quite nasty to station managers.

After analog shutdown, any station doing HD will not want to continue to keep two separate paths of different AR. It is too much of a pain the butt. The only reason stations are putting up with it now is because the majority of their audience is still in the 4:3 world. On Feb 17, 2009, there is no more motivation to continue to support that format so most stations will just tell the nastys to go fly a kite since it is not econonical to support two formats any further.


I know in my own station's case, we can hardy wait to stop supporting two AR formats. By supporting two formats, we really don't do either format justice anymore because we have to constantly be thinking how can we do X while keeping Y for the 4:3 viewers. It really sucks.
 

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Quote:
Originally Posted by foxeng /forum/post/0


I know in my own station's case, we can hardy wait to stop supporting two AR formats. By supporting two formats, we really don't do either format justice anymore because we have to constantly be thinking how can we do X while keeping Y for the 4:3 viewers. It really sucks.

Have you decided which AR to keep, and which to dump?
 

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Quote:
Originally Posted by sdk 009 /forum/post/0


One of the engineers at the CBS outlet in Sacramento posted a thread that confirmed their SD ATSC was fed via fiber to both D* & E*. If that's the case, why isn't the channel's audio in DD on D*.

DD takes up a lot of room compared to plain audio so D* and E* likely strip it.
 

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Quote:
Originally Posted by CPanther95 /forum/post/0


Have you decided which AR to keep, and which to dump?

Looks like NBC has already chosen as many of their shows are 16:9. (Can we call them the "letterbox leader"?)


On another note, maybe we'll soon see an end to "full screen" (4:3 cropped) DVD movies.
 
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