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Tivo HD Pixelation Troubleshooting

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

  1. Nov 25, 2007 #401 of 1597
    SMB-IL

    SMB-IL Member

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    Mar 5, 2003
    Chicago, IL
    It seems I posted too soon.... Clearing the RD folder didn't REALLY help, it just seemed to for a day or two. Comcast was out yesterday to see why after I upgraded the drive with one from Weaknees, I lost HBO, Showtime and Encore from my cablecards -- now one works and one doesn't, but that's another story. I also mentioned the pixelation and the service guy (straight out of "Twin Peaks", by the way) kept reporting to his dispatch that my signal was too strong. He put a tap on the line and the pixelation seems to have dropped a bit, but not completely. I live in a 24 unit apartment building and he commented that the signal was probably boosted for that reason.

    On the work order, he wrote that the levels for the CPE (which I believe is "Customer Premise Equipment") are a high of +20.8 and a low of +23.9. I happened to have kept the work order from when the cablecards for the Series 3 were originally installed and those readings (a little over a year ago) are a high of +7 and a low of +3. I know next to nothing about the magic of digital cable, but a year ago, my picture and signals were perfect and now they're pixeled -- even after the new HDD.

    Anyone that knows cable TV: would an attenuator or two to bring the signal strength back down to the 7/3 range help with the pixelation?
     
  2. Nov 28, 2007 #402 of 1597
    ingenue007

    ingenue007 UNLUCKY W/TW AUSTIN

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    Aug 22, 2005
    when i have pixelation issues, it makes my tivo reboot. then when i reach that spot it will reboot again. to get by it, i can fwd past that spot and then rewind somewhere ahead of the pixelation and watch it fine.

    is this common with everyone else?
     
  3. Nov 28, 2007 #403 of 1597
    wbradney

    wbradney New Member

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    Mar 3, 2003

    That sounds like a hard drive failure.
     
  4. Nov 28, 2007 #404 of 1597
    bweeston

    bweeston New Member

    27
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    Nov 23, 2007
    I just recently bought the Tivo HD box. I do not have any cable cards in it yet. But for the last 5 days, I've been transferring some high definition videos captured from MY HD capture card in a PC. Those videos are clean with no pixelation during playback on my PC. After transferring them to the THD and while playing them back, the pixelation occurs rather frequently and affects the sound output. These are HD with 5.1 audio captures. No solutions, but wanted all to know that this pixelation issue occurs without cable cards installed and while watching video not necessarily Live TV or TV recorded on the THD. I've also upgrade my hard drive space using the Tivo endorsed Western Digital My DVR Expander.
     
  5. Nov 28, 2007 #405 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    As wbradney mentioned, that does have the earmarks of a hard drive issue. You might want to run TiVo's diagnostic "kickstart 57" to see if that will clear things up.
     
  6. Nov 28, 2007 #406 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    I've had the same issue w/TiVoComeBack on HD programs. In fact I've seen issues going both ways w/HD content. It doesn't always happen (either way) but it seems like the HD content is very prone to problems when it is moved around. Sometimes I can reboot my router and it cleans things up. I don't blame it on TiVo though as I also have a PC HD DVR setup and I've seen the exact same things there.
     
  7. Nov 28, 2007 #407 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    16
    Oct 19, 2000
    No. VA/D.C.
    Should I install the attenuators at the input to each box, or can I do it downstream? My signal goes from ONT to switch that feeds upstairs S2, then a line that goes to a 3-output splitter, with two of those lines feeding two separate THDs.

    Both THDs show db levels of roughly +35, but I've only noticed pixels on one box, though I see uncorrected errors on both in diagnostics (granted, I'm not watching the second box on a daily basis as its my media room with Projector and only gets weekend use for most part.
     
  8. Nov 29, 2007 #408 of 1597
    egorss78

    egorss78 New Member

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    Jan 12, 2003
    I just recently started to get pixelation on one channel in particular(NBC HD). Ever other channel seems fine. I rebooted the Tivo and it seems to clear up for an hour or so. I am about to call Comcast, but have a feeling they will say it is the tivo. Any troubleshooting ideas I should try?
     
  9. Nov 29, 2007 #409 of 1597
    SMB-IL

    SMB-IL Member

    39
    0
    Mar 5, 2003
    Chicago, IL
    Can anyone explain how it is that Comcast is saying that my signal is too strong (20.8 - 23.9) and yet the channels with the worst pixelating are the ones with the lowest signal strength on the TiVo signal strength meter? Is Comcast's signal strength related to what shows on the TiVo?

    The signal was SO bad this morning that most of the channels just showed a black screen, except the channels that have been historically the strongest signals like MTV-HD, ESPN-HD, and MOJO-HD. I've tried the attenuators on the cable line and that only made it worse. I'm kind of at a loss....
     
  10. Nov 29, 2007 #410 of 1597
    SCSIRAID

    SCSIRAID Active Member

    2,321
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    Feb 2, 2003
    Vero Beach, FL
    Where are you getting the 20.8/23.9 numbers? What are the units? dbm?
    Are you sure these arent signal to noise ratio numbers? SNR.

    20dbm from a cablecompany is a HUGE signal level.... and would probably drive the tuner crazy. Like lhorer said... it would be like trying to scream and talk to someone standing next to a concert speaker. Adding attenuation should help. However a 20db SNR is horrible. Adding attenuation in this case would hurt. The Tivo should be showing a signal strength in the 80's or 90's with an SNR in the mid 30's.
     
  11. Nov 29, 2007 #411 of 1597
    btwyx

    btwyx Substantive Member

    11,331
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    Jan 16, 2003
    Mountain...
    The TiVo is a measure of signal quality. If the signal is too strong, the tuner overloads and can not recover the bits, the quality is lower. So increasing the actual signal strength can reduce the signal "strength" as reported by the TiVo.

    If too much signal is your problem, that's the easiest thing to fix with an attenuator.
     
  12. Nov 30, 2007 #412 of 1597
    wilhouse

    wilhouse New Member

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    Jul 13, 2003
    attenuation only seems to work for some people, and I have heard that it is those with FIOS (fiber optic) systems.

    I have RG6 from comcast, and I purchased a slew of attenuators. There was no appreciable difference from unattenuated at 34-35 to attenuated (32, 31 and below 31).

    wilhouse
     
  13. Dec 1, 2007 #413 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    16
    Oct 19, 2000
    No. VA/D.C.
    OK, well with my FiOS setup, attenuation doesn't work. Anything greater than -10db attenuator kills the signal totally. -10 takes me down to roughly +27db SNR and still get uncorrected errors. Here's the thing though...on one THD box, there's absolutely no problems or pixelization that I've seen. Running diagnostics on both THD boxes at same time and one is fine but the other will block/pixel whenever you press a button on the TiVo (both lines are fed from the same splitter. This has to be something to do with the boxes themselves and/or the software...but it's really strange it's some boxes and not others.
     
  14. Dec 2, 2007 #414 of 1597
    AbMagFab

    AbMagFab What happened, TiVo?

    3,638
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    Feb 5, 2001
    More likely, it's your cabling, as that's the main difference, and most likely to effect signal quality.

    If you really think it's the box, try swapping boxes, and see if the problem follows the box, or stays with the location.
     
  15. Dec 2, 2007 #415 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    16
    Oct 19, 2000
    No. VA/D.C.
    The reason I think its the boxes is 1) the cabling is the same to both locations and 2) both boxes show roughly the same signal strength and number of uncorrected errors at the same time when on the same channels, but box 1 will be blocking and box 2 handles it with no issues.

    When I say "roughly the same" I'm running up and down stairs to view each box diagnostic screen on the same channel at the same time, not true side by side :D

    I was lucky enough to win a THD in a contest that should arrive soon. I might just swap it out for the one having the issues.

    The other thing that is wacky is that the FiOS signal itself must change a bit. When watching the issue over the past couple of days, the problem box has had no blocking and when doing diagnostics on the same channels that typically block (such as Food 144), at the same db and signal strengths as last night, I was getting 0 uncorrected errors for 2-4 days straight -- just last night the problem cropped up again.
     
  16. Dec 2, 2007 #416 of 1597
    AbMagFab

    AbMagFab What happened, TiVo?

    3,638
    0
    Feb 5, 2001

    I agree - the FIOS signal does change throughout the day. Before I fixed my pixellation problems (using attenuators), it would be fine from around 10am to 3pm, then it would be bad, on a few channels. But the channel block would change. It would usually be within one or two frequencies, but the frequencies would change week to week.

    Weird.

    To your point, it's still not the same. You have different connectors, different ports on the splitter, and different physical cables for at least some portion of the run.

    Things like the shielding touching a connector can cause havoc, sometimes random.

    I'd strongly suggest you just swap Tivo's with each other, and see if the problem follows the Tivo. If it does, it's likely a hardware problem. If not, it's something in the cabling/connectors/splitter.
     
  17. Dec 2, 2007 #417 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    16
    Oct 19, 2000
    No. VA/D.C.
    That is a good point. I actually may do a short direct run with another cable (I had to pull a second line for my previous DirecTV setup for dual tuner) that won't go to the wall plate and take it straight to the problem box to see what happens. I think I've eliminated the main line splitter, as I switched placement on the splitter between both THDs with no difference. Switching boxes would be last step, as redoing the AV stacks is a real PITA
     
  18. Dec 3, 2007 #418 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    16
    Oct 19, 2000
    No. VA/D.C.
    AbMagFab, you may be a genius. I switched around some of the cabling leading to the problem box, and while I still get uncorrected errors and can't get rid of that using attenuation, it looks like the blocking has been eliminated for the time being....
     
  19. Dec 3, 2007 #419 of 1597
    SMB-IL

    SMB-IL Member

    39
    0
    Mar 5, 2003
    Chicago, IL
    The numbers were written on the work order by the tech when he was at the house. He kept telling his dispatch that the signal was really high.

    Hopefully an end to my problems: I called Comcast on Thursday morning because the pixelation was so bad on Thursday morning that most channels just showed a black screen. So I called from work and the rep wanted me to be at home to "troubleshoot". When I got home Thursday, the picture was perfect on all channels and the signal strength on the TiVo was back to the 80s and 90s and it's been that way ever since. I don't know what they did, but it worked and I'm hoping it stays working!
     
  20. Dec 3, 2007 #420 of 1597
    SCSIRAID

    SCSIRAID Active Member

    2,321
    0
    Feb 2, 2003
    Vero Beach, FL
    Excellent!!!

    What is the SNR?
     

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