Pixelation on One Channel

[Boris]

Hi,

I'm on the San Mateo, CA channel lineup. On one channel, and one channel
only, channel 16, which is ION, the picture pixelates at least 3-4 times a
minute, for about 2 seconds. And, the audio is about 1/2 second out of
synch with the video. This is on all the TVs in my house.

Over the weekend, I travelled to Santa Cruz, CA, about 50 miles away, and
at the hotel I stayed in, the same thing was going on. Sorry, but I don't
know if the Santa Cruz hotel had Comcast (they couldn't tell me), but they
had the same channel lineup.

Could the company that packages whatever Comcast sends to me have a problem
with just one channel in the lineup?

I like ION, and can't watch it without eventually having to change the
channel.

[Adam H. Kerman]

ION is a network of local over-the-air broadcast channels. Each channel
uplinks the same feed to satellite that it transmits via its antenna.
The interference could be at the satellite uplink, or at the downlink
in the head end, or some equipment in the head end.

Unless you call the Comcast help desk, there's zero chance of the
problem getting resolved if it's on Comcast's end.

[microsys]

Boris

Up here in Oakland the same problem has appeared over the last week or so that I
have noticed. It looks like somewhere along the line there is a faulty TBC (
Time Base Corrector) not only do I see pixelization but there is color shifting
as well. The color between the commercials and the program material exhibits a
major change in phase. It appears the color burst is not locked to the
horizontal sync as specified in rs170a. Sometimes during the shift from program
to commercial and the other way around the hue will be purple for a few frames
until things slowly lock back up.

The problem rarely exceeds the point where it's unwatchable but then again I am
not always focused on the screen. I agree it's pretty ugly and it will screw up
for 15 seconds or even more at times. I would probably feel the way you describe
if there was audio static equivalent to the video disruption. From what I can
tell the problem appears to be originating at the source rather than Comcast
although that's pure speculation on my part.

[Seth Goodman]

In article <ju61jo$cbc$1...@dont-email.me>, micr...@spamsucks.void wrote:
> From what I can
> tell the problem appears to be originating at the source rather than Comcast
> although that's pure speculation on my part.

A quick Google on "ion channel pixelation" shows pixelation complaints
from AT&T Uverse customers as well as Comcast customers in multiple
areas, supporting your speculation the problem is at the source.

--
Seth Goodman

[Adam H. Kerman]

microsys <micr...@spamsucks.void> wrote:

>Up here in Oakland the same problem has appeared over the last week or
>so that I
>have noticed. It looks like somewhere along the line there is a faulty TBC (
>Time Base Corrector) not only do I see pixelization but there is color shifting
>as well. The color between the commercials and the program material exhibits a
>major change in phase. It appears the color burst is not locked to the
>horizontal sync as specified in rs170a. Sometimes during the shift from
>program
>to commercial and the other way around the hue will be purple for a few frames
>until things slowly lock back up.

What does TBC do?

[microsys]

Adam

Bill provides a nice link to the function of a TBC and I can add a bit more to
explain the pixelization problem. Basically the TBC relies on a reference signal
, usually black, to sync all the video through the facility. The black reference
signal consists of horizontal and vertical sync pulses along with color burst
and black reference level. Since video is required to be at specific levels with
specific timing and the sync pulses both horizontal and vertical along with
color reference are critical, these signals are replaced at the TBC. Incoming
video to the TBC, will have it's reference signals stripped and the TBC replaces
that information with the system wide reference.

In the US we use a standard called NTSC and prior to about the mid 1980's this
meant ( Never Twice The Same Color ). The problem was that the color burst
information was not referenced to anything. The phase of the 13 cycles of burst
at 3.58Mhz were free floating with respect to the rest of the signal. This
created havoc when video was edited to include commercials. Of course this was
not only evident in content to commercial shifts but in edits between different
sources of video.

The standard at that time was rs170 and it was changed in the early to mid 80's
to require the reference color burst information be phase locked with the
horizontal sync pulse. Hence (rs170-a). The end result was the color phase shift
between various content sources was always the same. No more of these wild
shifts where people would have purple faces for a few frames.

The other thing a TBC does is to replace bad video with the last good lines of
video. I am not sure how many lines of video get stored in the buffer these days
but back then it was something like 22 lines. The need was based on things like
tape drop outs.. ( yep..they used tape in those days ) Consider that when there
were enough dropouts to cause disturbance to the viewer it was simple enough to
replace those dropouts with the previous lines of good stuff and the viewer
would not even notice it. I might add that in those days tape was the culprit
and these days loss of digital information via over the air transmission is a
major player. Looks like we traded medium but have not solved the problem.

To my eye ION exhibits the inability to replace the last lines of good video or
the loss of information exceeds the TBC's abilities hence the viewer sees
sections of pixels stuck on the screen while video moves around it. It appears
to me something like bad memory on a computer where everything works except when
running something memory intensive and the computer crashes. The color shifts I
see appear to me as if the system wide black reference signal has been lost thus
causing off color video.

[microsys]

Seth

A very nice bit of sleuthing on your part. Makes sense to me.

[Adam H. Kerman]

microsys <micr...@spamsucks.void> wrote:

>Bill provides a nice link to the function of a TBC and I can add a bit more to
>explain the pixelization problem. Basically the TBC relies on a

>reference signal . . .

Thank you. That was all very interesting.

[Boris]

Seth Goodman <seth...@yahoo.com> wrote in
news:MPG.2a7081e2f...@news.eternal-september.org:

Interesting, I hadn't thought of a google search <g>. But, I just did
one on 'ion pixelation', and I got two interesting hits. One, on a
comcast forum dated 7/15/12, describing the same thing on ION. The only
response was from a 'Most Valued Poster', who responded ...it's usually a
network issue which will clear up.

The second hit was on an ATT forum, from July 2008, in which a Chicago
resident described the same thing on his ION (ch. 38 there) station.

[Adam H. Kerman]

Boris <nos...@nospam.invalid> wrote:

>Seth Goodman <seth...@yahoo.com> wrote:
>>micr...@spamsucks.void wrote:

>>>From what I can
>>>tell the problem appears to be originating at the source rather than
>>>Comcast although that's pure speculation on my part.

>>A quick Google on "ion channel pixelation" shows pixelation complaints
>>from AT&T Uverse customers as well as Comcast customers in multiple
>>areas, supporting your speculation the problem is at the source.

>Interesting, I hadn't thought of a google search <g>. But, I just did
>one on 'ion pixelation', and I got two interesting hits. One, on a
>comcast forum dated 7/15/12, describing the same thing on ION. The only
>response was from a 'Most Valued Poster', who responded ...it's usually a
>network issue which will clear up.

>The second hit was on an ATT forum, from July 2008, in which a Chicago
>resident described the same thing on his ION (ch. 38 there) station.

So the local broadcast affiliates are receiving a bad feed and in turn
supplying that bad feed to Comcast.

With all the local station engineers, you'd think one of them could have
called his counterpart at the network to get it fixed by this time.

[Boris]

"Adam H. Kerman" <a...@chinet.com> wrote in
news:ju7pb4$cot$1...@news.albasani.net:

You'd think.

I did respond the 'Most Valued Poster' on the comcast forum, saying:

"Actually, I believe the problem is with the supplier of ION. While I
began to experience it here a week ago or so, only on ION, on all the TVs
in my house, I was in Santa Cruz over the weekend, and stayed in a motel
that supplied ION, and the EXACT problem existed there. If you google
this issue, you'll also find that ATT Uverse has the same problem with
ION.

So, can this be fixed? That's the question."

We'll see, but I'm not holding my breath. Not that 'Most Valued Poster'
can fix it, but perhaps, as has been my experience in the past, comcast
has it's own lurkers that read the forums, and have sometimes escalated
issues to engineers. I just want to be able to watch ION.

[Adam H. Kerman]

Boris <nos...@nospam.invalid> wrote:

Call the broadcast engineer at your local affiliate. I've found these
guys are very responsive, although it might take a day or two to get
you a callback.

Stick up an antenna and see if you experience the same problem, but that
would certainly confirm it's with the local affiliate's signal (passing
along a bad network signal).

[Boris]

"Adam H. Kerman" <a...@chinet.com> wrote in
news:ju80bi$hvl$1...@news.albasani.net:

Local affiliate? All I can ever get a hold of is the national number,
and they won't give out numbers for my local office, I've asked before.
And when I do call the national number, I get the script monkeys. How
does one get a hold of a broadcast engineer (esp. for my area)?

Thanks.

[Boris]

Bill <no...@none.invalid> wrote in
news:fm4f081ifpn3m8431...@4ax.com:

> On Thu, 19 Jul 2012 04:41:22 +0000 (UTC), Boris

> You've probably already tried leaving a message here:
> <http://www.iontelevision.com/contact/>

Nope. Hadn't thought of it.
>
> What I did just now was Google my local ION channel by it's call
> letters. The first hit included the studio address and phone number.
> You can probably do the same and get the phone number for your local
> affiliate. Call during normal business hours and ask for the broadcast
> engineer. You'll probably get the person's voicemail, but that's a
> start.
>

I will definitely try all of that.

Thanks.

[Adam H. Kerman]

Nothing beats ye olde white pages phone directory. Television and radio
stations are listed by call letter by W or K, depending on which part
of the country you're in. If worst comes to worse, find it on the
FCC Web site. That these guys are contactible is a condition of
license.

[cameo]

Comcast is often changing frequencies of various TV channels which may
result in some channels suffering more signal loss over a given distance
then others. Usually the higher the frequency the greater the signal
loss. In your case it may be that your ION signal was just marginal to
begin with and if Comcast increased the channel's frequency, it caused
too much signal drop to provide solid video. This is when you start
seeing pixelated picture.

I don't see what else Comcast could do in such case but boost the signal
level in the main cable on your street or give you a booster to install
at your cable box inside the house. Perhaps just upgrading your home's
cabling and with better splitter arraingement could accomplish the same
thing.

[Boris]

Bill <no...@none.invalid> wrote in
news:td8f089tkj3rls5ne...@4ax.com:

> On Thu, 19 Jul 2012 05:12:15 +0000 (UTC), Boris

> As you probably saw, that page also contains the following note:
> "To report technical or signal problems relating to the network,
> please fill out the form, or call us at 888-467-2988."
>
> Is that the number you've been calling? Since it's for reporting
> technical problems, I would hope that the folks who answer it are
> somewhat trained in technical matters or at least can forward you to
> someone who is.

>
>>>
>>> What I did just now was Google my local ION channel by it's call
>>> letters. The first hit included the studio address and phone number.
>>> You can probably do the same and get the phone number for your local
>>> affiliate. Call during normal business hours and ask for the
>>> broadcast engineer. You'll probably get the person's voicemail, but
>>> that's a start.
>>>
>>
>>I will definitely try all of that.
>>
>>Thanks.
>

> No Problem. Good luck.
>

Wednesday, I went to the ION site you gave, and contacted their
technical department through email, explaining the situation. I got the
standard auto-response, which is fine.

Last night, Thursday, I watched a full hour episode of my favorite
program, with no pixelation and the audio/video was in sync. And, even
when going in and out of commercial breaks, all was well. I'll probably
never know if 'the fix was in', or notifying them started the ball
rolling. No matter, I just hope it stays fixed.

Thanks to all.

[Glaasgok]

"Boris" <nos...@nospam.invalid> wrote in message
news:XnsA093CD17C2200n...@88.198.244.100...

I'm on the east coast of FLA., a long way from you, and I get this regularly
on several different, and changing, channels. I had lack of sound sync on
ABC one night, CNBC another night. Scroll down in the list a few weeks and
you'll find protracted episodes. So while it could be anything, I think
it's comcast.