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Tivo HD Pixelation Troubleshooting

Discussion in 'TiVo Series3 HDTV DVRs' started by Chimpware, Aug 3, 2007.

  1. Jun 17, 2008 #781 of 1597
    hmm52

    hmm52 New Member

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    Yeah, I'm a jackass for living with the problem for so long while I knew the distribution amp should be considered suspect. It was on the list but relegated to the time of making antenna changes before next February. Brain lockup. All it would have taken was ant. coax disconnect. The info has been in this forum in several places and I've counseled others to be cautious about boosting signals, on both the antenna and cable sides. My gut feeling was that moderate boost on the OTA side wouldn't cause havoc on the QAM side. Wrong. It actually made very strong signals appear very weak - no tune or heavy pixelation; very low or non existant values on diagnostics screen. Now I know why there were very few posting about a split as I had, seemingly - too high and too low signals. They were all too high.

    My S3 is much more vulnerable to off signals than the other equipment I have. Nothing else tiles to the severity and quantity of channels that it does. And I've certainly never seen anything else lockup, freeze and reboot in response to Verizon's poorer efforts. But it can be simply remedied with just attenuation ( and dist. amp removal) so I can easily live with that. In an effort to stop any RS Uncorrected accumulation on every channel (Starz HD), I added a 3db attenuator to the 8db- OCD to the bitter end. Channels checked now have SS fluctuating from low 60s to mid 70s and SNR at 31/32db. All OK. 8db clipped into Toshiba feed for locals; all OK there too.

    --------------- I'm very curious if attenuation puts a stop to the lockup, freeze, reboot syndrome for other S3 owners as well - the one where a coax disconnect frees up the machine. Though I hadn't seen it much before with dist. amp in place, it happened every time upon reboot without it. The benefit of then adding attenuator was immediate and obvious. I doubt my VZ signals will get much worse than they are currently (crossed fingers) and I've still got a bag of attenuators left over. So anybody stuck in a seriously repetitive lockup, freeze, reboot cycle with their S3 is more than welcome to try some that I have.

    In truth it was the severity of the problems caused by VZ's signal recently which finally caused me to check the ant. dist amp's influence. With Wimbledon a week away, even one of the Sonys was struggling with the ESPN HDs (nothing else). They're the backups. Not tolerable. I'll probably do a quick check of the recently manufactured S3 when it arrives, then send it back. I didn't really want to lose or copy the recordings anyway; now at around 850GB. The people that contacted me from the TiVo exec.'s office have been a pleasure to work with. It's unfortunate that all who have issues with their TiVos don't generally have the same access.
     
  2. Jun 17, 2008 #782 of 1597
    hmm52

    hmm52 New Member

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    I left out many details because my posts run too long with limited info. There are some curious things about the channel signals which caused the lockup, video freeze, then reboot. They seem to be in a different category than the 8 local HDs, as they also had seemed before disconnection of ant. distribution amp. When they displayed without attenuator for a minute or so until reboot, there wasn't any pixelation. Their diagnostics showed SS & SNR fixed at 100 & 37 unlike the locals which fluctuate wildly. I doubt the local HDs without attenuator would cause freeze and reboot. I'll test this as I don't mind experimenting - not with the ant. dist. amp again however.
     
  3. Jun 17, 2008 #783 of 1597
    richsadams

    richsadams Active Member

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    Jan 4, 2003
    Looking forward to the results. :up:
     
  4. Jun 19, 2008 #784 of 1597
    lateknight

    lateknight New Member

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    Mar 4, 2007
    So I had been experiencing tiling only on Comedy Central and Discovery (which meant I was missing Dirty Jobs and Futurama...unacceptable). Turns out that I had a signal strength of 45 and Uncorrected errors in the tens of thousands on those channels. Looking down my coax lines it turns out that I had a cheap splitter that was causing the problem. I took it out and signal strength is 98-100. No more tiling! Plus all my other channels look much better. Thanks for all the info guys!
     
  5. Jun 19, 2008 #785 of 1597
    richsadams

    richsadams Active Member

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    Jan 4, 2003
    Good news and perhaps valuable info for others. :up:
     
  6. Jun 28, 2008 #786 of 1597
    heel5man

    heel5man New Member

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    Jun 28, 2008
    I am a newbie to Tivo. I purchased a Series 3 HD and a HD model. Charter Cable came out today and with a typically bad attitude and poor execution only ended up getting 1 out of 4 requested cable cards installed. They showed up with 2 and one of them "didn't work."

    The good news is that all of the channels I pay for are coming in. The bad news is that I get a picture and audio that "skip" quite often, seemingly on most HD channels including locals from cable.

    In looking through the forums, the troubleshooting that I could understand, I did. This included restarting the unit. When that didn't fix it, I unplugged the power and coax which also hasn't helped. I tried calling Tivo support and the rep who was very nice told me that I had a "known issue" for which Tivo would be releasing an update for in the next week. I wanted to believe him, but after reading these forums I am doubtful.

    So here I am, looking for some help. I understand the stats from the Cable Card are important in diagnosis, so here they are:


    Tuner: 0
    Current Tuning Status: Not Tuned: General Tune Error?
    Channel -
    (all else blank)

    Tuner 1
    Modulation: QAM 256
    Frequency: 675000 KHz
    SNR: 37 dB
    RS Uncorrected: 0
    RSCorrected: 31905 (and rising rapidly as I type)

    CableCard: 2
    Module State: Not Inserted (waiting on Charter to come back with a good one)

    CableCARd: 1
    Module State: Operating Normally
    OOB Frequency: 75250 KHz
    OOB data Rate: 2048 Kbps
    OOB SNR: fluctuating between 20 and 22 dB

    I have no idea what ANY of these stats mean, so I would really appreciate some interpretation and troubleshooting advice.
     
  7. Jun 28, 2008 #787 of 1597
    SCSIRAID

    SCSIRAID Active Member

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    Feb 2, 2003
    Vero Beach, FL
    With a 37db SNR I would guess that you are overloaded and need some attenuation. Suggest 3-6db attenuation.
     
  8. Jul 18, 2008 #788 of 1597
    esb1981

    esb1981 New Member

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    Dec 2, 2007
    Connecticut
    I've had pixelation return a few weeks ago after not having any on channels I watch for some time. What happened is Cox added a few new HD channels - unfortunately they are virtually unwatchable due to the pixelation. But I've found an interesting common thread with some of the pixelation I've had in the past -- it's the frequencies the channels are carried on. In the past, I had trouble on a couple (thought not all) channels carried on frequencies between 645 MHz and 689 MHz. The pixelation disappeared, but this was because the channels were moved to other frequencies. Sure enough, the new HD channels are on those frequencies.

    So now with the pixelation back on the new channels, I am wondering if this means there is some problem with interference at those frequencies. I've replaced all of my cabling and connections that go from the basement to the Tivo. There is only one piece of cable that goes to a separate TV that has not been replaced. Is it possible that the interference is happening because the tuners inside the Tivo are not shielded well? Is there a way to better shield them? Any thoughts?
     
  9. Jul 18, 2008 #789 of 1597
    hmm52

    hmm52 New Member

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    Until I caught it, I did have pixelation caused by amplified OTA feed bleeding through tuner 0 QAM tuning. I don't know what the separation is between ATSC and QAM tuning but it wasn't enough to prevent this from happening - on one tuner only. I still use a preamp with antenna but have antenuators at both cable and antenna inputs. All is well.

    I've only seen pixelation matched to specific frequencies. It has affected other devices besides TiVo similarly and on the same channels, but to a lesser degree. Other than what I noted above, it's always been the signal quality as delivered by Verizon. Attenuators don't eliminate your pixelation?
     
  10. Jul 18, 2008 #790 of 1597
    esb1981

    esb1981 New Member

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    Dec 2, 2007
    Connecticut
    Thanks for the response - that does support my theory to some extent, I guess. Attenuators help with the pixelation, but depending on the severity of the specific channel they don't completely eliminate it. I've had issues pop up in the past and been able to eliminate the pixelation with the attenuators, but no such luck this time. Right now I have it attenuated down as far as I can without losing other channels due to low signal, the pixelation is still severe on a couple channels. I don't have an antenna in play, so it can't be that. I do know there is an HD VHF station about 8 miles away that I can pick up with a coathanger, but that's obviously a much lower frequency than the 650-700 where I'm having the problems. A while back I used a plastic terminator to cover the antenna-in connector on the Tivo, but that didn't help.
     
  11. Jul 18, 2008 #791 of 1597
    hmm52

    hmm52 New Member

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    No offense, but your experience is exactly the type I'd rather not hear of. I had the same problem in February when sufficient attenuation for local HDs clipped many other channels too much - low signal pixelation and signal dropouts. Hookup antenna. Then 3 months of good signals - no attenuators or antenna needed. One month kind of bad mostly for locals around analog dropping time. Catastrophic periods were July/August & November last year. I would be surprised if there isn't something similar with coming channel additions. When all else fails, pour yourself a drink, call Verizon and tell them to get there sh*t together.
     
  12. Jul 18, 2008 #792 of 1597
    esb1981

    esb1981 New Member

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    Dec 2, 2007
    Connecticut
    Yeah, believe me, I've long since resorted to the pouring on a drink to get me through this! And I've felt all along that it's Cox's fault in their signals, but figured maybe I had suddenly discovered something. I just don't know if I have the energy to deal with them - have another tech come out and claim he's testing the signal and then tell me there's nothing wrong.
     
  13. Jul 18, 2008 #793 of 1597
    hmm52

    hmm52 New Member

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    There is another way. It requires a mental adjustment however--

    When things got seriously awful on the bedroom Toshiba last year, I dropped the thought of watching TV on it altogether. (The Sonys were mostly fine) I turned on the Toshiba just to see my own in house work of art worthy of the MOMA - possibly titled "Explosion of Digital Mosaics" circa 2007. I don't remember what stimulant/depressant I used to bend my mind around on this issue. It got be by though.

    After weeks of crap, it all cleared overnight. Central Ofiice problems supposedly. Many COs were out of sorts at that time though. Looking into it later, my perspective was that percentage complaining was too low. Passive customers get what in return? Sometimes electronic art.
     
  14. Aug 2, 2008 #794 of 1597
    harkov

    harkov New Member

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    Dec 2, 2007
    I've been having pixelation problems with my local HD channels for the last week. This problem has not effected any of my other HD channels, but has made the locals unwatchable.
     
  15. Aug 2, 2008 #795 of 1597
    richsadams

    richsadams Active Member

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    Jan 4, 2003
    We had that happen one time and it turned out to be a cableco issue. Most (all?) cableco's run local channels within a certain frequency range and if things get out of whack some or all of the channels in that range display problems. It took them a day or so after the tech left but eventually they got things cleared up (said something about changes that were accidentally made at the "head end" :confused:) I'd ring them up and see if they can't get things straightened out for you.

    Good luck and let us know what you find out.
     
  16. Aug 2, 2008 #796 of 1597
    hmm52

    hmm52 New Member

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    Hey Rich,

    Long time, no direct replies. You a FiOS customer yet? I've been pretty inactive on the TCF recently as there's been a zillion things going on in my life (mostly good to great thankfully). Not much TV watching but I'm very curious how 9.4 pans out just the same.

    I have a small quibble with your previous post here. Did you mean to say that it is a frequency range problem? In my experience and in the read of others in this thread, the local HDs are the most common offenders regardless of what range they occupy on the spectrum. Just above and just below are fine while the locals are semi-chronic pixelators. I've needed to use attenuators here since 1st or 2nd week of June, only for the locals. Antenna would have worked also for them except for other local problem - forecasts of heavy storms each night during endless heat wave. Choose one feed's channels or another's and stay with it. I have the sense that cableco.s (Verizon) tend to juice the local HDs.

    Maybe few care much about the S3 lockup and THD freeze issues now other than whether 9.4 or a new HDD offers a solution. I'm still curious as to what is/was going on as my S3 was prone to it an average of once per week. From what I observed with mine, you gave the most plausible explanation awhile back (can't find it of course).

    I don't know squat about computers but corrupted data in the buffer stongly seemed at fault. The one time I was able to stay in the contaminated sliding buffer, I saw the 10% corrupted section over and over again - Think of "A Clockwork Orange" indoctrination sequence. Once 30 minutes had elapsed, real time was rejoined and all was well. No reboot. every freeze/lockup/reboot I have witnessed has exactly coincided with TV turn on. During 8 & 10 hour recordings of Wimbledon, no problems as long as TV completely on or off throughout Two consecutive days with turning on to check - lockup and reboot. I think there were signai issues which didn't manifest as pixelation but did make the S3 vulnerable to lockup. When a transient event happened, even with component video hookup, a freeze was triggered. I have no idea what the transient could be with CV hookup, but the symptoms suggest this. Early this week I held off reboot after first lockup symptoms arrived. But all recordings were inaccessible; something like "recording failed as no signal was present". Reboot and all was OK, live and recorded. The corrupted buffer had also interfered with recording playback. Reboots, manual and automatic, seem to be the TiVo's bulldozer method of purging the bad buffer. I know my theory's simplistic. Any thoughts? No bad behavior since 9.4 a few nights ago.

    ------I rarely have the S3 recording 2 channels at once so I don't know what it's capable of. I didn't know it was capable of this: Tennis recording on one tuner. Time slipping Keith Obermann on other tuner. Scheduled recording channel change message appears just before 9:00. Select OK to change channels, so both tuners are recording tennis from 9:00 on. But with MSNBC buffer I am still able to watch final 10 minutes of K.O.mann. At end of same, video switches to beginning of that tuner's tennis program. Very cool. The Sony DVRs could never pull off something like that. A channel change means a channel change; buffer be gone. Is this new with 9.4 or was this capability always there?
     
  17. Aug 3, 2008 #797 of 1597
    richsadams

    richsadams Active Member

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    Hey there...long time no hear! You didn't miss a lot...same problems (for the most part), different day. Glad to hear that good things are coming your way.

    We're not on FIOS...yet The last person I saw in an orange vest climbing back into a Verizon truck said everything was done in our little neighborhood as far as she was concerned. I'm wondering when they will let us in. Hopefully their billing dept. will improve by then...yeah, right. :rolleyes:

    My SWAG about why v9.3x caused so many folks problems was that it was due to an O/S change which demanded more of TiVo's hard drives than it could handle; specifically the meager 2MB cache. Many folks could unplug their coax or avoid HD programming and everything was okay. The high throughput might have been the culprit. Replacing the OEM drive with an off-the-shelf model (almost all of which come with 8 to 32MB of cache) always seemed to resolve things. Pure speculation on my part though.

    The good news is...so far it seems that v9.4 has addressed the video freeze and IIRC S3 lock-up/reboot issues. Woo hoo! I doubt if this upgrade is perfect either, but so far, so good. One thing I've noticed, and it's probably just my imagination, but I think my HD PQ is better since v9.4! :confused: I have no explanation as to why that might be, and again, it may be that I'm just seeing things, but it seems like the picture is clearer and brighter than before. We hardly watch any SD programs, so can't say if they look better too, but maybe I'll have a look later.

    Agreed that the local HD channels are the worst offenders when it comes to macroblocking, etc. We've experienced that, particularly with the NBC affiliate. They suffered some serious A/V issues for a while. Seems that it's better now. My understanding was that most or all of the local broadcast stations would be found in a particular frequency band within the cableco's signal. My guesstimate was that if the OP was seeing only local HD problems that it was likely a cableco issue and not his or her TiVo as that was our experience once (and the source of the frequency info), but there could well be another explanation.

    Your description of the video freeze when your TV was on/off immediately made me think it was an HDMI handshake issue, but if the same thing happened with component connections that shoots my theory down. I guess the only other way to see if it's your TV or TiVo causing the problem would be to hook up another TV to see if you can replicate it. What a pain! Again, according to a number of other posts here and there it would seem that v9.4 has taken care of a lot of those kinds of issues. Fingers crossed.

    I'm not sure about the channel switching you speak of. I remember someone (TiVoJerry?) saying that the next upgrade (which would be v9.4) would let TiVo continue recording on the same channel if the next scheduled recording was on that channel...whereas before it would switch tuners. I do have instances of that programmed (NBC nightly news immediately followed by the local news for instance), but I'll have to wait until Monday to see if it works. It was an annoying "bug" of sorts when it did that before so I'll be happy if they kept their word.

    Good to hear from you and keep the posts coming! :up:
     
  18. Aug 4, 2008 #798 of 1597
    hmm52

    hmm52 New Member

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    I should clarify some things in my post.

    Having used 5 cablecard devices for a long time, it is easy for me to separate signal feed and TiVo problems. In my experience, pixelation is absolutely the fault of the cableco's feed (Verizon). TiVos are more vulnerable than most devices to it, but the catastrophic times were with a Toshiba TV long before I bought the S3. If the signal tolerances were more closely maintained, there would be no pixelation on either the Toshiba or S3 - w/o attenuators. Fortunately this is usually the case and this year has been much better than last year. Fingers crossed...

    I referred to my suspicion of signal errors/problems which don't result in pixelation but may factor in freeze/reboots cycles. Twice this Spring I noticed something odd with the two ESPN HDs. Twice for 10 - 30 minutes at a time, they were untunable by the S3 and 2 Sony DVRs. But they were easily tuned by the Sony and Toshiba TVs throughout these periods. It was as if ESPN was testing out a message, "we don't want you time slipping or recording our programming". No other channels, including their SDs, behaved this way then or ever. When my S3 has locked up, it has usually been on one of these 2 channels, both non-pixelators. Coincidence?

    Regarding the TV turn on transient, it is hard to test because lockups are somewhat rare and I don't have a spare TV that's easily moved or feel like moving the TiVo. S Video out is a possibility (Ugh), I guess. The first post 9.4 reboot occurred yesterday; 15 minute cycling with green screen. I suppose both HDDs are suspect because the 750gb Seagate is mentioned often in earlier S3 lockup posts. Once or even twice a week reboots won't kill me. Yeah, I'm lazy. These are entertainment machines. No?

    Last week I was amazed that the S3 allowed watching the buffer to the end from one channel while scheduled recordings were taking place on 2 other channels - MSNBC, ESPN2HD, and the Tennis Channel. 10 minutes of buffer remained from MSNBC when its tuner switched to the Tennis Channel at 9:00PM. When finished with MSNBC at 9:10PM, the display turned back to the beginning of the TC program - 9:00 PM. So essentially the S3 was buffering/recording 2 channels while holding the buffer of a third. I have not seen this before on any DVR. The Sonys drop the buffer immediately upon channel change (one tuner & up to 90 minutes of buffer). I had thought the TiVos did the same thing.
     
  19. Aug 4, 2008 #799 of 1597
    gwsat

    gwsat New Member

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    Sep 14, 2006
    Oklahoma City
    Recently, I noticed that my S3 was holding the buffer of a channel I was watching, although 2 other programs had started to record on other channels. I was grateful but did not realize that it was that big a deal.
     
  20. Aug 4, 2008 #800 of 1597
    hmm52

    hmm52 New Member

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    If you had been exclusively using HD DVRs for TV since October 2005 but had never seen this ability before, it would be a big deal. Maybe it was always so with the S3, but I just never noticed. Rarely do I use the two tuners for simultaneous recording. Rarer still is the time slip buffering with scheduled recording offset situation.

    I'm glad to know it exists so I don't have to rush through a buffered program on the free tuner before a recording begins; or set the first up for programmed recording at the last minute.- Not difficult; just inconvenient and distracting.
     

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