Can someone confirm ...?

The local WCBS - 2 NY here currently has no subchannels, & people credit that for increased HD quality/bandwith ....
Once the Feb '09 Digital only goes into effect ... It is my understanding that currently most local HD channels were given a temporary license to use 2 frequencies per market, 1 to continue their existing analog SD channel, & another for DTV/HD feeds.........
in WCBS's case, VHF ch 2 as always, + their currently used newer HD channel frequency ( on UHF , I think ..) ....
in '09, WCBS & the others will have to give up one (1) of their 2 frequencies .... & combine all feeds/subchannels onto 1 frequency transmitted digitally...

So, this means that WCBS will have at least 1 subchannel along with their HD, for their SD feed, starting in '09 ... correct?

Can someone confirm ...?

The local WCBS - 2 NY here currently has no subchannels, & people credit that for increased HD quality/bandwith ....
Once the Feb '09 Digital only goes into effect ... It is my understanding that currently most local HD channels were given a temporary license to use 2 frequencies per market, 1 to continue their existing SD channel, & another for DTV/HD feeds.........
in WCBS's case, VHF ch 2 as always, + their currently used newer HD channel frequency ( on UHF , I think ..) ....
in '09, WCBS & the others will have to give up one (1) of their 2 frequencies .... & combine all feeds/subchannels onto 1 frequency transmitted digitally...

So, this means that WCBS will have at least 1 subchannel along with their HD, for their SD feed, starting in '09 ... correct?Why would they have an SD feed after Feb '09?

in '09, WCBS & the others will have to give up one (1) of their 2 frequencies ....This part is correct, although it's not necessarily the station's choice which frequency they give up.
& combine all feeds/subchannels onto 1 frequency transmitted digitally...There are no subchannels on analog channels. There is nothing to combine...

I wish WNBC would get rid of their useless subchannels, maybe it would make their picture worth watching

Why would they have an SD feed after Feb '09?

Plenty of people will still need a SD digital feed after Feb '09...

It's only an analog shutdown.... most people won't be HD-ready

Plenty of people will still need a SD digital feed after Feb '09...

It's only an analog shutdown.... most people won't be HD-ready

Any digital tuner should be able to tune the HD channel and display in letterbox or center-cut if the TV is not wide screen HD ready. SD feeds are not necessary... If the viewer doesn't have a digital tuner they're out of luck anyway.

Why would they have an SD feed after Feb '09?
SD feed For the millions of Cable & OTA users that still use a non HD set in 1 or more rooms.. Most Existing cable boxes for SD sets are not HD DTV tuners, & will not change, & will require an SD feed...

There are no subchannels on analog channels. There is nothing to combine...
No one is claiming there are subchannels on analog ...
However their HD & SD feeds will have to be combined once they give up the analog frequency ...
So again, it is my understanding that after FEB '09, the HD feed of the local digital CBS channel will include at least 1 subchannel for the SD feed, can anyone else confirm this??

SD feed For the millions of Cable & OTA users that still use a non HD set in 1 or more rooms.. OTA viewers will need a digital tuner or digital converter box (which is digital tuner). All digital tuners can tune and display the HD feed, even on an SD screen (the viewer of an SD screen will see it letterboxed or center cut). As for cable users, that is most likely the cable company's responsibility to convert the HD feed to SD for it's viewers if it wishes to provide that. This could be done on cable boxes themselves or they could do it before distrubution.


No one is claiming there are subchannels on analog ...
However their HD & SD feeds will have to be combined once they give up the analog frequency ...
So again, it is my understanding that after FEB '09, the HD feed of the local digital CBS channel will include at least 1 subchannel for the SD feed, can anyone else confirm this??
No, again, SD feeds will not be needed. There may be some stations that choose to provide an SD feed but it's completely unnecessary as digital tuners can already take the HD feed and convert to SD for viewers that need it.

OTA viewers will need a digital tuner or digital converter box (which is digital tuner). All digital tuners can tune and display the HD feed, even on an SD screen (the viewer of an SD screen will see it letterboxed or center cut). As for cable users, that is most likely the cable company's responsibility to convert the HD feed to SD for it's viewers if it wishes to provide that. This could be done on cable boxes themselves or they could do it before distrubution......

It has been my understanding that, at least for a while, all/most local HD broadcasters will continue to provide a digital SD feed (subchannel), for OTA digital settop converters & Cable Companies to pipe to their SD boxes ... .. I tend to doubt that all the SD locals will suddenly become downconverted cropped/ Letterboxed or zoomed versions of the HD feed in FEB '09 ....
If all or most Local network afill channels are shutting off their SD feeds the same day they shut down the analog channels .. That is news to me & contrary to most of what I have read so far ....
Hopefully someone with additional insight will chime in ....

It's a non-issue. You don't need an SD feed. The HD feed will be displayed as SD letterbox or center-cut. It would be redundant to broadcast 2 feeds, when 1 HD feed would be sufficient. I don't know why you think broadcasters would downcovert/crop all of a sudden, because that's essentially what they are doing now on the analog feeds.

It has been my understanding that, at least for a while, all/most local HD broadcasters will continue to provide a digital SD feed (subchannel), for OTA digital settop converters & Cable Companies to pipe to their SD boxes ... .. I tend to doubt that all the SD locals will suddenly become downconverted cropped/ Letterboxed or zoomed versions of the HD feed in FEB '09 ....
If all or most Local network afill channels are shutting off their SD feeds the same day they shut down the analog channels .. That is news to me & contrary to most of what I have read so far ....
Hopefully someone with additional insight will chime in ....
I know at least two stations here provide an SD digital version of their feed on a subchannel. I highly doubt they'll shut them off when analog goes away. It would kind of defeat the purpose if they dump them right when they'd potentially be needed.

Just because a tuner or converter box CAN convert an HD signal to SD, doesn't mean a local station will opt for that approach.

I know at least two stations here provide an SD digital version of their feed on a subchannel. I highly doubt they'll shut them off when analog goes away. It would kind of defeat the purpose if they dump them right when they'd potentially be needed.

Just because a tuner or converter box CAN convert an HD signal to SD, doesn't mean a local station will opt for that approach.
That's exactly my thinking as well ...

It has been my understanding that, at least for a while, all/most local HD broadcasters will continue to provide a digital SD feed (subchannel), for OTA digital settop converters & Cable Companies to pipe to their SD boxes ... .. I tend to doubt that all the SD locals will suddenly become downconverted cropped/ Letterboxed or zoomed versions of the HD feed in FEB '09 ....
If all or most Local network afill channels are shutting off their SD feeds the same day they shut down the analog channels .. That is news to me & contrary to most of what I have read so far ....
Hopefully someone with additional insight will chime in ....



There will be one ATSC Transport stream. For some stations, this will include an HD feed only. For some, it will be an HD program stream and 1-3 SD program streams. For some, it will be 1-4 SD program streams. Now in those other SD streams, some stations may choose to put a downconvert of their HD. But, this is not going to be what the majority does. The majority will do the HD and the recipient will determine if they want to center cut or letterbox it for their SD viewing pleasure.

Any digital tuner should be able to tune the HD channel and display in letterbox or center-cut if the TV is not wide screen HD ready. SD feeds are not necessary... If the viewer doesn't have a digital tuner they're out of luck anyway.

A SD feed WILL NOT be needed and a station would be really stupid to continue a separate feed that wastes bandwidth. Think about your HD cable box. If you hook it up to a SD TV or dump DVRed shows to VHS or DVD, the HD channels are output with letterbox bars. Although as technology changes, I'm sure other options will be available like horizontal compress or center-cut.

So, this means that WCBS will have at least 1 subchannel along with their HD, for their SD feed, starting in '09 ... correct?No.

Either now, or when the analog stations go off the air, it is up to the individual stations to decide how many subchannels to run on their digital channel. Since CBS owns WCBS, and a number of other stations, and they currently do not use subchannels, it would be very unlikely they add any at the cutoff.

They may well decide to add subchannels at some other point in time, but it will be unrelated to the analog cutoff.

...it would be redundant to broadcast 2 feeds, when 1 HD feed would be sufficient...

I wish somebody would tell SC-ETV this. They currently carry 3 channels on their DT transmitters here statewide: a 1080i stream with the PBS "HD" lineup, a 480i stream with a SD version of the analog station programming, and a special interest "SC Channel". Of late the prime time PBS lineup is the same on the SD and HD side, so we wind up geting the same program twice from the DT transmitter (and a 3rd copy from the analog transmitter!) all of which are carried by the TWC system.

Of course it's a waste of bandwith, and the HD PQ suffers as the ATSC stream is often over-burderned. In our local threads we've made this point to the SC-ETV Chief Engineer, but they have elected to continue the present arrangement until the analog shutoff, if not beyond.

I wish WNBC would get rid of their useless subchannels, maybe it would make their picture worth watching
Amen to that!

.. & when "The Tube" channel went belly-up, the local CW ch11 NYC now continued the subchannel transmission with an SD feed of their SD analog channel...
They too should shut off the subchannel & return bandwidth to their HD feed ....

If a station really wants to keep an SD feed going to cable headends, it could just fiber one over, couldn't it? No need to involve the digital air chain at all, I wouldn't think. The only commercial broadcaster here who WAS running an SD sub just stopped, last month. Wasn't necessary.

In NYC, 3 locals have SD feeds as a subchannel...

WPIX (CW11) runs its SD feed on 11.2
WWOR (My9) runs a Fox5 SD feed on 9.2
WNYW (Fox5) runs a My9 SD feed on 5.2

From what I understand, its done for backup purposes.... and I have (bad) a feeling this may become the norm

A SD feed WILL NOT be needed and a station would be really stupid to continue a separate feed that wastes bandwidth.
I hate to tell you, but plenty of OTA stations waste bandwidth on subchannels that are much less useful. You're assuming every station cares about the quality of their HD feed. If they did, none of them would ever run subchannels.

Most stations are concerned only with ensuring their core SD audience has the easiest access to a feed that fits their 4x3 screens. Asking them to mess in a converter box menu to centercut an HD feed is like asking a camel to play dominos.

The issue of proper downconversion is further complicated by the plans in the not too distant future for the elimination of SD distribution by the networks. Even if a station has a separate SD stream, what do they do with the HD network feed? Using center cut only may cause desired image elements to be cropped, while letterbox only will cause windowbox (aka postage stamp effect) on 4:3 material.

The answer is AFD (Active Format Descriptor) which allows the video signal to control the downconversion method (letterbox, center cut or somewhere in between) performed by the receiver or display. This method is already in use in some 576/50i based regions such as the UK. US broadcasters have been unfortunately slow to adopt this system. NBC is using it internally with Miranda products. Obviously this adds to the workflow for the broadcasters as each program element requires the proper flagging.

I don't know how much support there is with consumer equipment but I suspect it's not widespread yet. I think converter boxes purchased with the government coupons should be required to support AFD. Even with automatic control, the downconversion process should have manual override capability. With their near non-existent support for AFD, this would appear to be their current strategy.

This issue is obviously transitory as it will fade with the demise of 4:3 displays. If the broadcasters drag their feet long enough the problem will take care of itself.

If a station really wants to keep an SD feed going to cable headends, it could just fiber one over, couldn't it? No need to involve the digital air chain at all, I wouldn't think. The only commercial broadcaster here who WAS running an SD sub just stopped, last month. Wasn't necessary.
Just get the cable head end to put in for coupon for a free DTV STB. (I know the coupon is only good for 40 bucks off, but it's possible that the converters won't cost even that much, if you believe what was shown at CES.)

Don't give me any BS about the quality not being good enough. If you've ever seen the quality of the SD feeds on DTV or the digital simulcast of SD channels on cable, a DTV STB would kick a$$.

If a station really wants to keep an SD feed going to cable headends, it could just fiber one over, couldn't it? No need to involve the digital air chain at all, I wouldn't think.
Believe NBC's 4.4 channel on NYC's TWC is an example of this. WNBC-DT's Weather+ is OTA and cable, but NBC4.4 fibered to TWC is a variety of independently produced shows and local news. [EDIT: Corrected in my EDIT2 post below.]-- John

Believe NBC's 4.4 channel on NYC's TWC is an example of this. WNBC-DT's Weather+ is OTA and cable, but NBC4.4 fibered to TWC is a variety of independently produced shows and local news. -- John

Wa?

Everyone (all cable and OTA) gets the same content:
Weather+ on 4.2..
"WNBC4.4" on 4.4...

TWC doesn't get anything different

I Get the 4.4 channel on Fios, & assumed it was a subchannel as well.

In NYC, 3 locals have SD feeds as a subchannel...

WPIX (CW11) runs its SD feed on 11.2
WWOR (My9) runs a Fox5 SD feed on 9.2
WNYW (Fox5) runs a My9 SD feed on 5.2

From what I understand, its done for backup purposes.... and I have (bad) a feeling this may become the norm
WWOR and WNYW make some sort of sense...if you can't get the DT 5 signal, you can get at least some form of WNYW, or vice versa. WPIX is just beyond me. I watch it, because WPIX stupidly crops to 14:9. WNET should have an SD subchannel. The HD feed has a totally different schedule.

[AFD] is already in use in some 576/50i based regions such as the UK.

Apples and oranges. In the UK, the video is either anamorphic widescreen or true 4:3. There is a compromise with analog transmissions in that it is 14:9.

The AFD just tells the TV that the video is either 16:9 anamorphic or 4:3 and to set the display accordingly. I do not know if you can tell the set to centercut the 16:9 though. I'd have to ask my UK friend if his set can, or if it can only display letterboxed 16:9. Those changes are a little annoying when it happens.

I doubt that the current ATSC spec has PSIP bits allocations for aspect ratio info. It would be neat for a converter box to receive such info and display 16:9 HD either as letterbox or pan-n-noscanm depending on the user's choice. But, these boxes are supposed to be cheap and to add that would add cost.

Interesting idea though.

Weather+ on 4.2..
"WNBC4.4" on 4.4...

OK, where is 4.1 and 4.3?

I wish somebody would tell SC-ETV this. They currently carry 3 channels on their DT transmitters here statewide: a 1080i stream with the PBS "HD" lineup, a 480i stream with a SD version of the analog station programming, and a special interest "SC Channel".

Consider yourself lucky. Wiconsin Public Television (WPT) has FIVE streams, 4 SD and 1 HD. Fine print follows ---

During the weekday, the 4 SD streams have PBS programming of various types. One of the streams is the WPT analog channel. One of the others is Create. Don't remember the others, because I don't watch. During this time, the HD stream is only running a billboard that says that programming will resume at 7pm that night. When that happens, three of the SD streams go into billboard mode announcing there return in the morning. The WPT analog is always going.

They know the bitrate allocation sucks. Even though the billboards are static, they still eat up valuable bits. While I was out with my friend at our normal Friday Fish Fry, he bitched about the horrible video during one of the wood working shows he likes. I explained why. He his technically savvy, but hasn't really dug into ATSC and how it works. He asks me those questions :-) He has been supporting WPT with his donation and mentioned that he plans on letting them know that he will stop doing so if they don't do something about the video problem.

The odds of WPT scaling back their DTV streams are slim to none.

I hate to tell you, but plenty of OTA stations waste bandwidth on subchannels that are much less useful. You're assuming every station cares about the quality of their HD feed. If they did, none of them would ever run subchannels.

I agree and disagree with the above. I agree that subchannels are wasteful.

Stations, as a whole (i.e. all of the employees) not caring about HD quality is not true. There are many a station engineer that does care about HD quality, but are hamstrung by idiotic managers that see $$$ by running subchannels.

It is the idiots with the ties too tight around their necks that are messing with picture quality. Of course, the low bitrate that ATSC has in the first doesn't help any. If you could see MPEG-2 at twice the max available ATSC bitrate, you'd hate to watch OTA HD again.

Most stations are concerned only with ensuring their core SD audience has the easiest access to a feed that fits their 4x3 screens. Asking them to mess in a converter box menu to centercut an HD feed is like asking a camel to play dominos.

No, the stations I've see only care about $$$. Of the two commercial stations locally that have subchannels (out of 5), one runs that stupid MyNetworkTV and the other runs their local version of 24-7 weather. Both of which are there soley for added $$$ income.

Saying that aspect ratio is the only thing that J6P has to think about, and possibly not understand (even though there is a lot more letterboxed shows on SD these days), is forgetting about the potential problem of that person punching in the analog channel number and getting nothing, because the digital channel is not where the viewer thinks it is. Not one of our local stations is returning to their analog roots. Some have asked, but the FCC turned them down. If you think that getting the viewer to RTFM and figure out aspect ratio settings is also saying that said user won't read the manual and run the autoscan feature to find the digital channels.

It is going to be interesting when Feb 2009 roles around.

Wa?

Everyone (all cable and OTA) gets the same content:
Weather+ on 4.2..
"WNBC4.4" on 4.4...

TWC doesn't get anything different
That's what I thought all along, too. Having two subchannels might well account for all the complaints from OTA viewers about motion artifacting within the main 1080i.

Can't tune OTA here anymore. But if you can tune NBC4.4 OTA, that sure settles that. Recall Googling NBC4.4 a while back and something I read implied it was cable only. -- John

EDIT: Also, just searched local forum NYC OTA for "NBC4.4" with no hits...maybe it's listed differently, but seems it would arise with WNBC-DT complaints.

EDIT2: Just Googled "WNBC-DT subchannels" and found an '06 article (http://tvtech.com/pages/s.0082/t.390.html) mentioning WNBC-DT has two subchannels. Thanks, Berk32, for catching that error; I'll make corrections elsewhere.