1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Tivo HD Pixelation Troubleshooting

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

  1. Sep 26, 2008 #901 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    Cool that AMEX is coming through. Sad that TiVo wouldn't provide docs, but at least they talked to them. Good luck and keep us posted.
     
  2. Sep 28, 2008 #902 of 1597
    traig

    traig New Member

    6
    0
    Apr 4, 2007
    I live in Germantown, MD (Washington DC area) and noticed a significant issue with pixelation / blocking recently, but only with LOCAL HD channels (channels 504-526). I have a Tivo HD with two cable cards and service with FIOS. As far as I am able to determine, I only have issues with channels using the 513 or 519 Mhz frequency (local NBC, FOX, PBS, etc). Channels that use other frequencies, like CNN-HD at 231 Mhz, or USA-HD at 135 Mhz, or HD-NET at 723 Mhz, give me no trouble at all.

    When tuned to the local HD channels, I get signal strength that varies almost every second from the 40s up to 100, SNR anywhere from 30 to 35, and the RS corrected and uncorrected error counts climb constantly (unc in the 100k+ and cor in the millions after half an hour). This does not happen with standard channels or non-local HD. The problem will happen on both tuners, and is entirely specific to local HD channels.

    I have already ordered attenuators from Smarthome, but I wonder if applying attenuation would help in this case? Is anyone else seeing issues with local HD only (or the reverse), or with specific frequencies only?
     
  3. Sep 29, 2008 #903 of 1597
    kealoha311

    kealoha311 New Member

    16
    0
    Dec 4, 2001
    Hillsboro,...
    That's exactly how my pixelation is and attenuation makes it a lot better. I also have to disconnect the other side of the splitter that goes to the Actiontec router, and that gets me to about 99.9% pixelation free on the problematic frequencies.
     
  4. Sep 29, 2008 #904 of 1597
    ursa99

    ursa99 New Member

    35
    0
    Aug 21, 2005
    Yes, I'm seeing something very similar. A wildly bouncing signal and pixelization that renders the picture unwatchable for short periods. The pixelization happens ocassionally, sometimes at 8:00PM each night for several hours. All my affected channels are in the 411,000 to 429,000 frequency range. I have a low pass filter installed at the ONT and have tried attenuation from 8db up to 24db with no success. I think FIOS puts out a dirty signal once and a while and TIVO's tuners cannot correct the RS errors it creates. Verizon's tuners see the same dirty signal but have better error correction so the errors don't show up as pixelization....
     
  5. Sep 30, 2008 #905 of 1597
    traig

    traig New Member

    6
    0
    Apr 4, 2007
    To follow-up on my post, I received the attenuators yesterday and put -16dB in the line right before the connection to the TivoHD. The results were immediately positive. Tuning in to the local NBC and FOX HD stations, 504 and 505, I saw the RS Uncorrected errors stop incrementing. RS Corrected errors continued to creep up but with much smaller numbers than what I had seen before attaching the attenuators.

    Signal strength seemed to lock in between 60 and 80, SNR around 31-32. (Before I applied the attenuators signal strength was anywhere from 0 to 100, changing every second, with RS Cor and Unc climbing steadily. Again, this was only with a particular subset of HD stations, "local" ones.)

    So far so good. I also experimented with increasing and decreasing the attenuation. At -19dB it was also effective, but all it served to do was decrease the signal strength below 60. At -12 and -9 dB I saw the pixelation return with an increasing RS Uncorrected error count. -16 dB was the right combination for me.
     
  6. Oct 1, 2008 #906 of 1597
    Timster-MA

    Timster-MA New Member

    4
    0
    Oct 1, 2008
    Holliston Ma
    I have read through a lot of this note.

    I am in Holliston Mass and am using Verizon FIOS. I changed over from Comcast in the beginning of August. I am using a Tivo S3 with 2 cablecards from Verizon.

    Lately (last month or so) the local HD channels are getting lots of pixelization. I have checked over the connections and tried all the suggestions the phone tech support offered.

    The thing I noticed was that the signal strength for 504 ( CBSHD ) is significantly lower than other channels like ESPN ( 570 ) or HBO 899+. When the pixelization occurs the signal strength has typically dipped into the low 80s or high 70s.

    Today a truck came out and did the following:

    1 all connections cables were inspected and tightened
    2 ONT cleaned and tightened
    3 low pass filter tried
    4 cablecard swapped
    5 changed HDMI input to HDMI2 on tv
    6 tried tivo -> tv via component cable
    7 attenuator inserted to get ch 55 down to -17db ( as per some internal Verizon memo )

    The first 6 steps had no effect at all on the problem.

    The attenuator seems to have improved the watchability but there still is a problem although much less frequent.


    My thought is that since the issues appear to be with CBSHD, ABCHD, FoxHD and Ch56HD (all local channels) can I add an Over the Air antenna and try to receive the Local HD OTA, while using the cable for all the other channels? Essentially using both RF inputs to the TIVO at the same time

    In the TIVO guide, I read that I can recive 4-1 (CBSHD) as 4 ->| 1 with the skip button inserting the "-".

    While I am not happy with this solution, if it fixed my local station issues I could live with it. The problem only occurs on 4-5 channels all betwen 504 and 512 on the Verizon cable channel listing.

    So my question here is Can I use an OTA antenna in addition to FIOS cable and tune to 4-1 for CBSHD?, 25-1 for FoxHD?

    If so, will doing this have some programming guide issues? ie I might have to do manual recording for local HD channels?

    Any thoughts on this before I go out and try to buy an OTA antenna would be appreciated.

    Thanks

    Tim
     
  7. Oct 3, 2008 #907 of 1597
    jgerber

    jgerber New Member

    12
    0
    May 15, 2007
    Amex did give me a full refund of the S3 purchase price, which I'm definitely happy about. I'm still going about trying to determine the cause of the problem and to see if I can fix it. I've got a number of things to try this weekend, including a hard drive replacement, so I'm still hopeful - though I did do the kickstart drive diagnostics, and also pulled it into my PC and ran the WD diagnostics, and everything came out fine.

    Maybe it is in fact the tuner electronics, but I'm still doubtful. I'll be really surprised, and frustrated, if it turns out to be something on the motherboard. That said, at least I am not out the cash and can replace the unit.
     
  8. Oct 5, 2008 #908 of 1597
    proudx

    proudx New Member

    198
    0
    Sep 16, 2008
    http://www.tivocommunity.com/tivo-vb/showthread.php?t=407006

    I know this is related to digital cable signals received over cable cards. But I have discovered a serious problem with the Analog cable reception on the tuners as well. like you guys have discovered using attenuation to lower signal stregth to help reduce or illiminate pixelation I have a theory that the internal AGC mechanism over drives analogs creating dynamic changes in brightness on analog channels creating a flicker like illusion.

    If in fact the AGC circuit in the TIVO hds over drives digital/analog signals besides Attenuation is this something Tivo can fix with a software update or option to turn of AGC completely or reduce the aggresiveness of it?

    I tried out no less than 5 tivo hds, with manfuacturing dates of Jan,feb,apl and aug and all have this problem.
     
  9. Oct 6, 2008 #909 of 1597
    ciucca

    ciucca New Member

    270
    0
    Jun 29, 2004
    I would not hold my breath. I completely agree that there is a major hardware or software problem with the S3 and TIVOHD tuner circuitry. Since it has been years since this problem first appeared with no fix I'm sure it is a problem with the hardware.

    Good luck getting agreement from the majority on this board. Most will insist it is Verizon's fault. You want to save some headaches get a FIOS DVR and try it out for a while. It works very well. It has a feature TIVO does not, you can start playing a recording from the beginning if it is in the middle by picking a menu option, I haven't figured out how to do this on a Tivo. Also you can actually continue to watch TV while using the DVR menus to setup and record programs. To be fair the lack of adding additional storage is a negative. You pick your priorities , you want to pay top dollar for a product that causes you frustration, or do you want to just plug in and watch TV?
     
  10. Oct 6, 2008 #910 of 1597
    webin

    webin New Member

    307
    0
    Feb 13, 2008
    Hillsboro,...
    /sigh, welcome back ciucca. Suggesting someone abandons Tivo instead of engaging in the tivo-related discussion sorta defeats the purpose of having a discussion, doesn't it?

    In my opinion, the previous post was quite insightful, offering a "tuner fault" point of view that doesn't get enough coverage in our discussion of the topic.
     
  11. Oct 7, 2008 #911 of 1597
    jgerber

    jgerber New Member

    12
    0
    May 15, 2007
    My pixelation issue has been resolved by a hard drive replacement. As I stated before, Tivo tech support quickly identified a hardware problem (though the tech erroneously believed it to be with the tuner hardware) and acknowledged that to American Express' extended warranty program, who gave me a full refund of my purchase price 3 months after the factory warranty expired.

    Interestingly enough, the 250GB/2MB WD hard drive I removed from the Tivo passes all the diagnostic checks while installed in my PC. Regardless, installation of the new 750GB/16MB Seagate drive ($97 at Fry's) resolved the issue with a couple hours of work. After reading the various theories as to why this has happened with so many S3s, I think that Rich Adams' idea that the 2MB drive cache on the factory hard disk was insufficient to begin with, and one of the 9.x software updates changed something that causes the cache to overflow. Just a theory, I know, but it's as good a theory as I've read so far.

    Anyway, obviously my problem isn't the same as those that are dealing with signal strength issues, but overall it was a positive resolution. I'd recommend anyone that has similar problems on an out of warranty Tivo to take similar steps - use extended warranty coverage where possible, and replace your hard drive with one you buy locally that can be returned if it doesn't work.
     
  12. Oct 7, 2008 #912 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    Glad to hear things are back to "normal"...plus you have all that extra recording space now! :up: But it's a shame that people are having to replace their hard drives to correct the macroblocking/pixelization problem.

    I'm still racking my brain, but the miniscule cache on TiVo's OEM hard drive is the only thing I can think of as the culprit. It appears that resolution to the issue can be resolved by installing a drive with a larger cache (which is almost any drive on the shelf today)...but who knows? :confused:

    So if I'm reading your posts right...AMEX refunded your money, but you still have the same S3 and now it works? So a free S3 (less a new hard drive)? What a deal!
     
  13. Oct 7, 2008 #913 of 1597
    Gregor

    Gregor Active Member

    46,747
    14
    Feb 18, 2002
    Just as a data point, I've seen a pretty good reduction in pixellation over the past few weeks with FIOS.

    Dunno if they did something,but things are markedly better. :)
     
  14. Oct 7, 2008 #914 of 1597
    jgerber

    jgerber New Member

    12
    0
    May 15, 2007
    Well, I doubt Amex is monitoring this forum so I'm OK admitting it :) yes - essentially the hardware cost was zero plus the $100 for the new drive, plus a fair amount of frustration and a few hours' work (some opportunity cost there).

    I'm following your theory on the drive cache and it does make some sense. If the write queue to the drive overflows the cache, causing the CPU to stay at 100%, it would certainly cause the symptoms I experienced. Someone with a PROM'd S3 would likely be able to figure it out...maybe it doesn't matter though since so many of the cases are resolved with a hard drive replacement. Maybe it's not just the drive cache, but the combination of HDD/RAM/CPU sizing that's not working out.

    I also agree it's a shame that Tivo let this happen, but I doubt they anticipated it. Depending on how many are failing like this under warranty, though, it could be a very expensive planning mistake for them. It's also likely to cost them customers that are out of warranty and don't have the wherewithal to do the drive upgrade. I can imagine it driving customers to their cableco or ATT for a 'managed' DVR appliance.
     
  15. Oct 8, 2008 #915 of 1597
    jay_winter

    jay_winter P4+P4XL+Mini+FIOS

    74
    0
    Jan 13, 2004
    Richmond, VA
    I live in the southeast valley suburbs of Phoenix, and I started out last year with perfect reception from Cox Cable. But, for the past several months I had been putting up with sporadic one-or-two-second macroblocking/freeze-ups on most of my SD digital channels -- hoping that one TiVo update or another would eventually resolve the problem.
    My signal levels were always perfect, and uncorrected error counts = 0.

    After much prodding from my wife to do SOMETHING about the problem, I finally had Cox come out to figure out the problem. All of his testing confirmed my own, and even after upgrading the distribution amplifier and splitters in my "smart panel", nothing changed.

    Then he tried something else... he replaced the single-stream cable cards in my S3 to two new multi-stream ones (simply because that was what he had on-hand). Since then all my pixelation problems have vanished.

    I also have to plug Cox here, because, despite the complaints posted here from other users, I have had nothing but INCREDIBLE service support from Cox, and every tech they have ever sent out has been thoroughly familiar with cable cards --and TiVo/CC issues in particular.

    My only complaint with Cox is that I think their package deal costs too much.
    :up::up::up:
     
  16. Oct 8, 2008 #916 of 1597
    webin

    webin New Member

    307
    0
    Feb 13, 2008
    Hillsboro,...
    I haven't been tracking this factor as well as I should... are pixelation issues showing up just on S-Cards, or also on some M-Cards (among the tivo community at large, not just Jay)? Could the issue be related to manufacturing tolerances of the cable card as opposed to tivo's hardware? Over on the DSLReports forums, there are occasionally people complaining of pixelation on the FiOS set-top-boxes. I'm wondering if those are the new ones using cable card decoders....
     
  17. Oct 8, 2008 #917 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    Good points neighbor. Cable cards have long been an issue with pixelization, freezing, etc. When the TiVo HD was first introduced there were a horrific amount of reported problems particularly with Scientific Atlanta (SA) cable cards. TiVo to their credit sent out several software updates to address the problem (although not nearly quickly enough for those suffering) and seems to have addressed most of the issues. However there continue to be cable card issues not only with TiVo but many other applications (visit the AVS Forum and others for more).

    Often time problems are resolved by replacing cable cards, but cableco's can be less than cooperative, choosing to blame TiVo's rather than faulty cards, cards that need firmware updates, etc. It's sort of understandable as they have no vested interest in working with anything but their own equipment. They often sight their own/proprietary DVR's as proof that everything is fine...that it's TiVo's fault when something isn't right. An apples and oranges argument for the most part IMO. That's not to say that TiVo's "tolerances" for signal issues aren't narrower or possibly lower than other DVR's, but there are thousands of TiVo's like ours working flawlessly so I don't think we can lay total blame at anyone's doorstep.

    That said the only thing most folks having problems have noted if they have SA, Motorola or one of the few other branded cable cards (Motos apparently being fairly stable), however I don't think we've been keeping track of any data points with respect to "S" Vs "M" card problems and AFAIK, Jay's report of switching from "S" to "M" cards is a first with respect to a resolution for his box...good news indeed.

    It would be valuable to know what brand and type of cable cards are changed out and what the results were. I've always said that there is no "silver bullet" for a fix, it's likely a laundry list of things that can cause issues, but the more knowledge we have, the better our chances of helping those that follow. :up:
     
  18. Oct 9, 2008 #918 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    Here's another post by someone that replaced their cards to resolve a problem:

     
  19. Oct 16, 2008 #919 of 1597
    hkancyr

    hkancyr New Member

    67
    0
    Jan 20, 2002
    CT
    Here's my problem resolution. (Hint:has nothing to do with cablecards or reception)
    I have recently received my most recent replacement HDTiVo. This is #3 and they decided to go with new rather than refurbished this time. All fine and dandy but, it did exactly the same as the previous TiVo's. Always, the HD channels pixelate then freeze. This only happens after I update to the newest software. Hmm. The other thing that happens with this upgrade is the ability to use the external storage. So now you know what ended up solving my problem, finally. I properly troubleshot the external HDD, found a problem and replaced it and all problems are now gone.
    Smooth HD sailing here boss.
     
  20. Oct 17, 2008 #920 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    Thanks for the report and glad to hear things are working now. Expansion drive problems have been the cause of a number of issues from pixelization to freezes to reboots. Often times replacing the eSATA cable takes care of it, sometimes it's the enclosure and others it's the hard drive itself.

    Did you figure out what exactly was wrong with your external drive? Can you give us details such as model, when you installed it, etc?

    TIA! :up:
     

Share This Page