Exactly How do Locals Work...and Who's Responsible

[LarryFlowers]

I've never read exactly how Network Affiliate local channels work... Earl can you explain?

I keep reading about local channel problems with HD broadcasting and everyone seems to be up in arms over it. The question is, who is responsible? Is NBC delivering garbage to the affiliates? Is WXIA, my local NBC affiliate responsible? Is DirecTV responsible?

I have seen the problem myself, I read all the posts about people being angry about it... but I don't see any information about what the problem is.

Someone/Some -Thing is at the root of this.

If it is a network level problem, then how about names and email addresses of the heads of the Networks HD engineering departments.

If its an affiliate issue, the same information for the locals.

If it is a D* problem, maybe the mods can fill us in.

I also know that there is at least one WXIA engineer on this site. Surely there are some Network or other affiliate engineers on the site as well who could weigh in?

[dbmaven]

Did you see this thread, stickied in the Programming Forum ?

http://www.dbstalk.com/showthread.php?t=68497

[Stuart Sweet]

I think you've run into the real issue: The huge number of people, from the studios to the networks to the affiliates to the guide data aggregators to the satellite provider... who all must be in perfect sync in order for things to work properly.

In the case of NBC I have to wonder if it's the encoders being used to send the data back to DIRECTV's satellites. I also wonder if the affected markets are using a direct feed from the affiliate or are they pulling it from an antenna.

[bonscott87]

NBC is widely known for being the worst HD in the industry.

If you have a problem with your local, 98% of the time it's with them. You'll see the same issues OTA as you do via DirecTV.

The best resource to start with is on the AVS HD Locals forum. See the links in my sig and find the thread for your city/area.

A great example right now is my local CBS. It has been *terrible* for over a week now. Lots of video/audio dropouts and terrible macroblocking. Well I might think it's a DirecTV problem but a quick look on my areas local HD thread on AVS reveals to me that *everyone* is seeing this problem: Charter, Comcast, OTA and DirecTV users all see it. Thus the problem is with my local station.

[LarryFlowers]

NBC is widely known for being the worst HD in the industry.

If you have a problem with your local, 98% of the time it's with them. You'll see the same issues OTA as you do via DirecTV.

The best resource to start with is on the AVS HD Locals forum. See the links in my sig and find the thread for your city/area.

A great example right now is my local CBS. It has been *terrible* for over a week now. Lots of video/audio dropouts and terrible macroblocking. Well I might think it's a DirecTV problem but a quick look on my areas local HD thread on AVS reveals to me that *everyone* is seeing this problem: Charter, Comcast, OTA and DirecTV users all see it. Thus the problem is with my local station.

The "irony" of the NBC problem is that they are in fact the test bed for all changes to the nations television signal, specifically, the Tonight Show.

[veryoldschool]

My local CBS HD is having really problems.
SD goes through fiber to the local D* office for up linking.
HD goes from the CBS studio to their tower [OTA] and the local D* office picks up the OTA signal.
I'd guess the network feed to the local station is the least of the problems.
What seems to be happening here is the OTA signal can have a glitch that will hang the D* receiver. While the OTA signal may recover, the D* receiver needs to be reset before it will function again.
Someday maybe everything will be through fiber.

[drded]

Here in Tucson, the CBS affiliate KOLD has super bad audio drop-outs and picture-blocking, yet they insist on running a sub channel for weather and old news.

Complaining to the engineering department results in them telling you to replace your OTA antenna, i.e. they are not admitting they have a problem.

The NBC and ABC affiliates are decent OTA signals (other than NBC doing so much in SD vs. HD). Rumor has it D* is supposed to be adding them soon, so we'll see how things are then.

Dave

[donshan]

Problems can develop at any of the points you list, and often the people involved do not know where the problem is in the chain. I don't understand it myself , but have learned enough to be impressed with the complexity of digital broadcasting. The links below concern just one small, but essential part of OTA broadcasting- the PSIP digital tables. If you want to see how complex this is just skim these two .pdf documents and look at some of the diagrams of all the components of just one part of the OTA system. It takes a very well trained geek to understand this stuff, and most station's can't afford this level of engineer full time.

Several years ago our local PBS station started the first HD broadcasts and I wrote to the station to congratulate them. This led to an interesting series of emails from their engineer who wanted my feedback on the Picture and sound. Some software issues developed that required the station to go off the air for a few days while a software consultant fixed the PSIP tables that are required data discussed in these links.

Eventually everything was working and now we get great PBS TV most of the time, but occasional glitches still occur on every OTA digital channel I get. Obviously if the station has the problem it will also be on the D* relay of it. The specifics of the D* digital system are another layer of digital complexity sending milliions of 1s and 0s to our HDTVs. When even one essential number does not get decoded properly, we experience a picture of sound glitch. With time these problems are getting corrected, but to appreciate their problem just skim these two documents.

I don't think any of us want or could understand a detailed analysis of how this digital "sausage" is really made!:D

http://www.psip.org/documents/BE_PSIP_06_June_2001.pdf

http://www.atsc.org/standards/a_69.pdf

[CPanther95]

NBC has severe issues distributing HD to its affiliates. Even rain in NYC can cause serious PQ problems with all affiliates.

Even if a decent signal makes it to the affiliate, you still face local issues such as multicasting which can introduce severe PQ issues with any motion - or incorrect encoder settings which can introduce things like the blur, or out of focus issue during NFL games whenever they come back from instant replay, etc.

The vast majority of times - D* is getting their HD-LIL feed from an antenna, so any multicasting (insufficient bandwidth) issues will also be present in the D* supplied locals. It is possible to get a "raw" feed from the affiliate, before any reduction in bandwidth, but it is very expensive - so obviously, it is also very rare.

[CPanther95]

More detail from a recent post 5 minutes ago from keenan @ AVS (yes, this NBC issue is discussed frequently):

Yes, NBC runs a Ku-band distro system for the digital signal as opposed to the other 3 nets which use C-band. Ku-band is the same as the system used by DirecTV to deliver their signals(not the new MPEG4 signals which are Ka, the original MPEG2) to their subscribers. Ku-band is more susceptible to adverse weather conditions. As CP noted, when there is a bad storm situation in the New York area, heavy rain, snow, blizzard, NBC has problems getting the signal out. It's happened on a somewhat regular basis during the heavy winter months each year.

It usually manifests itself as audio/video artifacts, loss of image, and finally you'll end up with no signal at all or an SD signal being fed from the local station encoders.

[Peapod]

If you have a problem with your local, 98% of the time it's with them. You'll see the same issues OTA as you do via DirecTV.

The best resource to start with is on the AVS HD Locals forum. See the links in my sig and find the thread for your city/area.

In the case of WXIA, the reported problems are confirmed as not happening OTA or on cable, but appear to be happening on Dish Network as well. This makes the AVS Forum threads useless, as they cover cable and OTA only. It appears that D* and E* share the uplink here in Atlanta, and that the equipment is faulty.

[bonscott87]

In the case of WXIA, the reported problems are confirmed as not happening OTA or on cable, but appear to be happening on Dish Network as well. This makes the AVS Forum threads useless, as they cover cable and OTA only. It appears that D* and E* share the uplink here in Atlanta, and that the equipment is faulty.

Sorry if your local thread is like that. We cover all cable, sat and OTA in our thread. Just depends who is posting.

[dtremain]

The "irony" of the NBC problem is that they are in fact the test bed for all changes to the nations television signal, specifically, the Tonight Show.That explains why Johnny Carson looks so different these days.:D

[CPanther95]

Sorry if your local thread is like that. We cover all cable, sat and OTA in our thread. Just depends who is posting.

Yep, it's all fair game. Generally there's little discussion of DBS technical issues because 99% of the time they are a result of the local affiliate (OTA discussion).

[Peapod]

Yep, it's all fair game. Generally there's little discussion of DBS technical issues because 99% of the time they are a result of the local affiliate (OTA discussion).

That may be the case in your thread, but I can assure you that it's not the case in the Atlanta OTA thread (from past personal experience). The Atlanta DBS thread only exists in the archive now, but a post in the OTA thread about DBS is considered 'off-topic'.

[CPanther95]

Start a new thread for Atlanta, GA - DBS with your issues and I'll add it to the index.

But even absent a DBS thread - DBS issues would be considered on-topic in the OTA thread until there's enough discussion to warrant a separate thread. If there are issues with that, I'll change the title to "OTA/DBS" to remove any resistance.

[veryoldschool]

Start a new thread for Atlanta, GA - DBS with your issues and I'll add it to the index.

But even absent a DBS thread - DBS issues would be considered on-topic in the OTA thread until there's enough discussion to warrant a separate thread. If there are issues with that, I'll change the title to "OTA/DBS" to remove any resistance.
I'd guess this "Allstar" here has another title over on AVS. :)

[CPanther95]

Shhhhhh !

I need a place where I can call people idiots with reckless abondon. ;)