Morac
join:2001-08-30
Riverside, NJ
 ·Comcast
|  Vertical Interlacing?
Simpsons scene change | 
Simpsons scene change 2 | 
Simpsons motion change. |
This only occurs when going through my digital cable box. All my channels are digital when going through my cable box, but many of the channels do not go into my cable plant as digital signals.
I had someone from Comcast come out and look at it, but they didn't seem to care. Also since I have a TiVo he said that could be causing it. I've since verified it occurs when bypassing the Tivo. It doesn't show up on VHS tapes because of the poor quality (even at SP), but it does show up when I record using "SVHS on VHS tape" mode on my VCR which produces higher quality recordings, but can only be played on VCRs that support such a feature.
Do you think there is a flaw in analog to digital encoding that Comcast is using in my area? Has anyone ever seen this before?
I've attached some examples. You'll need to look at the large version to see it.
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The Comcast Disney Avatar has been retired. |
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SpHeRe31459
join:2002-10-09
Sacramento, CA
1 edit | Are you sure all of your channels are digital? Many areas have not made the switch to digital simulcasting yet. That really looks like you have defective cable box or something... what model is your digital cable box? The old DCT-2000's which are still in wide use have some flaws like chroma upsampling errors but I have never seen this before. |
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Morac
join:2001-08-30
Riverside, NJ
·Comcast
1 edit | Yes I'm sure everything is digital. The diagnostic menu says as much and recently I've been having a low SNR and all channels through the cable box started macroblocking (and eventually were replaced by an error message). The only way I could watch TV was to bypass the box. The V.I. problem predates this problem though.
I do have an old DCT-2000, but it's been fine up till now though they apparently upgraded the firmware and software versions recently. Also the fact that certains channels don't experience this while others do leads me to believe it's not the box.
Also I don't want to give the impression that those lines are always there. They sometimes appear on scene changes and on motion, but not always. Fox and the WB seem to have a much higher chance of doing this than other stations.
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The Comcast Disney Avatar has been retired. |
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schja01
I need to get a life.
Premium,MVM
join:2000-04-27
Morton Grove, IL
clubs:  
 ·AT&T U-Verse
 ·AT&T Midwest
| reply to Morac
Since is only happens on scene changes it smacks of being MPEG artifacts.
I have no clue whether it's a comcast issue or cable box issue.
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"Have I said something amiss?" |
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bcunningh
join:2005-04-01
Seattle, WA | reply to Morac
Does this happen with analog cable direct to the tv (or Tivo)? |
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Morac
join:2001-08-30
Riverside, NJ
·Comcast
| said by bcunningh  :Does this happen with analog cable direct to the tv (or Tivo)? No
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The Comcast Disney Avatar has been retired. |
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Morac
join:2001-08-30
Riverside, NJ
·Comcast
| reply to Morac
I noticed that the channels I notice the problem on (see it all the time) are broadcast channels that have been converted to digital. I don't see it on channels that were digital to begin with.
I also noticed it in an old TiVo recording back from November 8, 2005 but it was barely noticeable there (I had to look for it to see it). So it may have existed since the change-over to all digital, but something triggered it to get worse.
At best it is only noticeable when going frame by frame through video, at worst it is noticeable when watching at normal speeds.
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The Comcast Disney Avatar has been retired. |
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Morac
join:2001-08-30
Riverside, NJ
·Comcast
| reply to Morac
Well I've had 2 people from Comcast out to look at this. One blaimed it on my TiVo so I bypassed my TiVo and recorded it on a VCR. The other blaimed in on my TV even though only certain channels are showing the problem. When I explained to him that I was using the S-Video in on my TV so it would show up on all channels he just insisted it was probably my TV and asked me to hook up another one.
It seems like the people coming out don't seem to know much about how TV actually works since what I'm seeing is obviously a digital problem and the only 2 digital components in my system are the TiVo (which I eliminated) and the cable box.
So the problem is either with the cable box (unlikely since it was working fine up until recently) or with the incoming signal. Since the incoming signal is digital, this means that it is either being decoded improperly by the box (again unlikely) or it wasn't encoded correctly.
I'm trying to get Comcast to look at the encoding part, but I can't reach anyone who even knows anything.
Any ideas?
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The Comcast Disney Avatar has been retired. |
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comcrashtic
join:2005-12-05
Littleton, CO
| Here's an idea. Find out where the local Comcast office is, disconnect your box, take it down there with a copy of your bill, and ask for a replacement box saying this one has some problems and you'd like a new one.
Then see if the problem goes away.
We have a similar problem here in Denver, and it turns out to be a Spanish language FM station bleeding over into their channel frequency spectrum from channels 65 - 95. It's a real bummer with no solution in sight until they convert those channels to digital (supposedly). When will that be? My Magic 8 Ball says "Ask Again Later", which is exactly what Comcast Customer No-service says. |
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jdiddy_installer
@comcast.net
| This is something I haven't seen before. This could be something with your box itself maybe a component inside the box is not working properly like a mixer or something. The first reasonable step in troubleshooting would be to change the box and see where you go from there. If you can't rule out the cable box the you need to replace that and then work backwards. Are your neighbors experiencing the same thing on there boxes? You guys would be sharing the same tap and everything so if they were not and you were that would mean the problem lies between the tap and your tv. If they are experiencing the same symptoms the problem is somewhere along the string back to the cable plant itself.
-Jdiddy |
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