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TiVoPony said:
Hey guys,

We are aware that some of you are still reporting macroblocking or pixelation on certain channels. The team here continues to gather information to understand possible causes - they're making good headway.

The update we released on August 1st has proven to fix the issue for some customers, and we are working hard on a fix for the remaining cases. We will provide more concrete information as we can.

In the meantime, we appreciate your patience and the detailed feedback you've been providing.

Pony
Pony,

Does your statement only pertain to the HD or does it also include the S3? My issue has been open since October on pixelation and dropouts with no aparrent progress or admission that there is a problem that is being worked on.
 

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jfh3 said:
If you swapped out the box in question and the problem remained, the odds are 99.99% that the problem is cable and not Tivo related.
Gee.. I guess the cableco had better get busy and fix itself since all those Tivo HD boxes CANNOT be the problem...... since you can replace the Tivo HD and have the same pixelation problem :rolleyes:

I guess my Samsung TV must have this secret special circuitry too since it has no problem with a cablecard.

Perhaps you should at least consider that there may be a better than .1% chance there is an undiagnosed design problem with the Tivo S3 QAM tuner/demod/forward error correction etc etc. Just because you dont see it, doesnt mean it doesnt exist.
 

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brermike said:
The guy is not talking about Tivo HD, but the original Series 3. See his original post. Since most people with the original Series 3 aren't having this problem, well, you figure the rest out.
I understand that. I was trying to make a point that just because you use a different unit and the problem remains doesnt automatically mean that the problem is the cableco.
 

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jfh3 said:
I didn't say that the Tivo HD boxes CAN'T be the problem, I said it was more likely to be a cable issue. Big difference.

(And yes, AFAIK, most CR TVs also have the additional circuitry in them)

When I got my first series 3, I had similar pixelization problems that others are reporting. I had very occasional issues with a Motorola DVR and didn't see any on a (high end) Sony TV. The first few times I had a tech out, I got "we don't see a problem, you're signal is fine, etc.", but was persistent, because it just didn't make sense to me. (Though I'll admit, my first reaction was to blame the Series 3).

As it turns out, Comcast found not one, but two problems that impacted me and everyone on my sub node. Once that was fixed, I had an in-spec signal and haven't had a single issue on the Series 3 or THD (except on the a1 level) since.

So - despite repeated claims "everything was fine", it wasn't. When they replaced the faulty equipment, the problems went away.

Some cable signal problems are easy (bad amp, too many splitters). Some aren't. Most installers are paid by the job, so they have incentive to leave as quickly as possible.

The cable companies know that their signals aren't always what they should be. Their solution was to use hardware that could compensate for this rather than have to deal with the service calls that would certainly result if those boxes just handled inspec signals. From their standpoint, probably cost effective, at least initially.

For now, anyone with a THD and SA cards - the onus is on Tivo to show the problem isn't a Tivo problem.

For anyone else, I stand by my position - it is far more likely for the pixelization problems to be cable related (either signal or compression) than it is for it to be the Tivo hardware.
But by placing a 99.9% probablility on the situation you basically DID say that it really must be the cableco. If you had said 'more than likely' then I would have whole heartedly agreed with you.

For the record, I have an S3 and have fought the pixelation problem since last September and have had cableco folks all over this thing. Even the regional technical supervisor has been here and checked the system out with no success. I dont have a bad amp since three have been tried and I have zero splitters.

You mention 'special circuitry'; can you shed any light on what you are talking about? Its interesting that in my situation, problems occur only on encrypted streams... unencrypted streams are perfect. If the signal is 'bad' is should be equally bad reguardless of the stream payload.

I really dont want to start a foodfight here :) but I get frustrated when I hear 'it must be a cableco problem'.
 

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jfh3 said:
OK, sorry I used 99.99% - how about "more than likely"? :)

I don't remember the specifics - I saw it in the recent NTCA filing with the FCC and someone else detailed the specifics. Not sure it really matters - Tivo doesn't have it.

That seems logical. In that particular case, I would frame that as a Tivo issue (likely related to CableCARD support), especially if you are convinced you have a good signal.

I never said that. If you can get the cable company to show that you have a good, in spec signal and have the proof to back it up, then I'd bang on Tivo.

That's exactly the approach I was going to take. In my case, I didn't need to go to Tivo, because it WAS a cable problem.
If you come across the tuner circuitry info again I would really appreciate a PM. Id like to understand what it is.
 

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bdlucas said:
Personally I don't buy this "additional circuitry" theory. My TiVo was working just fine with a very marginal signal of -16 dbmV (as measured by my cable modem on the same splitter). I haven't seen an evidence of a problem with the TiVo front end.

On the other hand, TiVo has acknowledged (and has a fix in text for) a software problem that causes pixellation.
Wow... -16 isnt marginal... its just plain terrible. :)

I dont buy it either... but am keeping an open mind. The tuners these boxes use are 'off the shelf' items. Its been said that the ATI tuner chipset in the Tivo HD is the same one that is in the current Scientific Atlanta cableboxes (although I cant state that as fact).

With my S3 situation, signal strength made no difference. Using amps and attenuators, I moved the level up and down with zero effect on the pixelation. Im setting at about +4 right now.

I have to wonder if the issue that bit Tivo HD may shed some light on what I am experiencing with S3. I do have SA cablecards. On the other hand, it could be something completely different.
 

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bdlucas said:
Yup, TiVo HD.

At the end of the day the number that really matters is the S/N ratio. In fact it appears to me that the TiVo HD signal strength meter seems to pretty much be tied to the S/N ratio, going up/down in increments of about seven for every db change in S/N ratio.

The reason signal level matters is that when it is low enough the front-end noise becomes significant relative to the signal level, compromising the S/N ratio. But the overall signal quality is really determined by the sum total of all sources of noise in the system, relative to the signal.
Yup. Using the measurement capability of the SA 8300 which I still have on another set, SNR varies between 31 and 34 db on the channels of interest. Setting up the two tuners on channels that I watch and see issues, 8300 indicates BER of 0 on each tuner after about 2 hours. This rate is very likely after the forward error correction has done its job as the native channel BER should be nonzero.
 
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