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Tivo HD Pixelation Troubleshooting

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

  1. plateau10

    plateau10 New Member

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    Dec 11, 2007
    I wonder if this will have a positive effect on my problem, which I actually only noticed for the first time last night.

    I've only had the box for exactly one week, so I haven't put in a lot of hours of watching, yet. I noticed glitches on three different recordings last night. They were short, lasting about one second. Loss of audio and some macroblocking or, don't know what to call it: a sort-of trailing effect during a scene change.

    Anyway, my setup is OTA-only with the RCA ANT1500 (little white box-shaped thing that is hanging on the wall behind the TV). I live about 3-4 miles from pretty much all the stations I receive. I was playing around a bit with the diagnostics this morning and noticed SNR for a few channels at around 31 or so, so maybe under certain circumstances it gets too strong, and that may be what I was seeing in my recordings. Unfortunately, while I'm a recent TiVoHD owner, I'm a long-time (almost 10 years) TiVo user, so I timeshift 100% of what I watch. Makes debugging this a bit harder.

    As it turns out while I was testing this morning I noticed pending restart, so I went ahead and restarted and was able to play for a few minutes with the D update. I unfortunately did see about 900 uncorrected almost immediately on one channel, but it seemed to stay there. I'll need to look at this some more to test different channels and look at both tuners.
     
  2. John C

    John C New Member

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    Sep 15, 2008
    The new firmware loaded last night. There is a promising boost in error performance on my system. On a particularly bad channel there was constant accumulation of uncorrected errors (1000's per minute). This morning, none in two hours.

    I will leave the live TV set to that channel over the weekend and see if it sticks.

    So far there seems to be a good benefit here.
     
  3. dlfl

    dlfl Cranky old novice

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    What is your signal source and region and do you have a tuning adapter?
     
  4. John C

    John C New Member

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    Sep 15, 2008
    Sorry for the late reply. I have been traveling.

    No Tuning adapter. I am in Massachusetts. FiOS is the source.

    The pixelation issue is, for all intents and purposes, gone. There are occasional corrected errors (about 1 or 2 an hour).

    Seems like a fix (knock wood). It was really annoying.

    John
     
  5. jchas41

    jchas41 New Member

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    Feb 5, 2009
    I had hoped this would help with my problems (TWC, Tuning Adapter), it did not. Still having major pixelation problems. Some programs are worse than others. I have noticed that since 11.0d my RS Corrected and Uncorrected errors have increased quite a lot. Since I can't seem to figure out why this is happening I think my only choice now is to pay the 50 bucks and have tivo send me a new machine...hopefully that helps.
     
  6. Aug 4, 2009 #1266 of 1597
    alleyooptroop

    alleyooptroop New Member

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    Jul 1, 2009
    hopefully this is the right thread to get info on my problem. my setup: 52" sony xbr9, tivo hd, verizon fios service all connected via hdmi. since day one i've had macroblocking on fast action scenes and scenes where there's drastic changes in light (like an explosion at night). i had the verizon hd dvr for a couple weeks before the tivo and don't remember having this picture issue.

    when verizon first came out to install the cable card, the tech installed an attenuator that brought it down to 31db and no uncorrected errors but the problem persisted. even after the 11.0d firmware upgrade i did not see any improvement. i removed the attenuator - same. i've had my tivo switched out with a new one - same.

    is this just a product of a digital signal on a large tv? would i have the same issue with directv or any other provider?
     
  7. Aug 5, 2009 #1267 of 1597
    brianlaudio

    brianlaudio New Member

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    Aug 5, 2009
    Hi,
    I'm new to this forum so please forgive me if this is a repeat on this topic -- I gave up part way through the 45+ screens of postings trying to digest the info to see if anyone had the same exact issue I have.

    Back in March, I bought an HDTV and a TiVo HD box. Comcast installed a dual-stream CableCard and all was well until a couple weeks ago. At that time we started experiencing pixelation problems that have grown worse. Now they get so bad as to render some channels unviewable along with dropouts of audio. However this comes and goes. For example, yesterday afternoon there was almost none of this on any channel I checked; last night it was really bad; this morning at 7am it was moderately bad, but by 8am had only minor glitches.

    Background data:
    - we have only one TV in the house connected to cable (old analog TV is relegated to games)
    - one splitter at cable entrance to house -- other branch goes to cablemodem
    - from Day 1, signal strength as read by TIVO 'gauge' has been upper 40s to upper 50s
    - signal level remains at these levels even at worst of pixelation problems
    - I didn't realize until today that the diag display that gives SNR did it per channel, but any time I've looked it seems to have been sitting at 30-32 dB
    - I have briefly connected the cable directly to the TV, bypassing the TiVo. That limits the channels I can compare, but those that I could -might- have been better w/o TiVo. Can't say for sure. However, this is immaterial in practice as I intend to use the TiVo as the tuner for the system
    - TiVo output goes to Onkyo A/V receiver and from there to the TV, all by HDMI. These all seem solid with other sources.

    Called out the Comcast tech; he arrived yesterday:
    - (oddly) started at TV and cable modem to look at signal strength and said they were low. (not sure why he didn't start at service entrance to house...) He replaced connectors, couplers and (lone) splitter in path to TV, commenting that since nothing has been done to the house since it was built 22+ years ago, guy installing CableCard should have "checked it out and cleaned things up" back in March.
    - signal strength meter on TIVO has now gained a good 10 points on all channels -- range of mid-50s to mid-60s after tweeks
    - finally reaching the service entrance to house (RG11 cable) his test box still found a 'weak signal' and 'lots of <unspecified> errors". Ditto when he went across the street to the on-the-ground distribution amp and splitter for our cul de sac (all buried utilities)
    - He put in a service order for a tech to check the distribution amp and whatever else might be a problem upstream
    - curiously, last Thursday some other dude in a Comcast truck was poking at the distribution amp for reasons unknown to me and I didn't have time to stop and ask him (I figured someone else was having the same problem as I was and had called in a complaint)
    - I'm an Electrical Engineer with 'a number of years' of experience, so I took some of the guy's comments with a grain of salt - "our splitter is better than your splitter" when he replaced it, and "our connector is better than your connector", etc.

    So, here is where I need advice. I'll give my conclusions; please let me know if I'm on the right track or not.

    - since I had several months w/o this problem, I find it hard to attribute it to a "TiVo tuner problem" as has been discussed on this thread. I can't imagine that the tuner just 'got weak'
    - that said, this is monsoon in Tucson, so along with heat we've had thunderstorms and some power glitches. However, this problem hasn't been correlated in time to storms -- i.e., haven't had any storms since a good week before the problems started, nor would that explain the worsening of the problem
    - I should take more detailed signal strength, SNR and error rate data by channel, both during pixelation episodes and when viewing is good
    - bottom line: I think the problems still point to a Comcast signal issue.

    thanks!
    brian

    p.s., can anyone tell me what the desired signal level on the incoming signal should be as measured on the Comcast guy's diagnostic box -- I think it read in units of dBmV.
     
  8. Aug 5, 2009 #1268 of 1597
    bkdtv

    bkdtv New Member

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    Jan 9, 2003
    DC Metro Area
    If your signal is in the 40s to 50s with a SNR of 30dB, you are going to have problems.

    You want a signal at least in the mid-60s and 70s, and a signal in the 80s would be much better. With my local Comcast, the signal is in the mid-90s with a SNR of 36-37dB.

    You want Comcast's own signal meter read -6dB or higher. The box only measures at certain frequencies, so if they report a low but "acceptable" signal, the signal on other frequencies could still be too weak to achieve the desired picture.

    You might consider a cable amplifier, although that isn't a solution in every case. If some form of RF interference is causing your problem, then an amplifier may not help.
     
  9. Aug 5, 2009 #1269 of 1597
    dlfl

    dlfl Cranky old novice

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    The TiVo support pages actually have some useful things to say about signal strength and quality issues.

    Here is an (abridged) excerpt:
    From my own very limited experience and many posts on this forum, I would say weak signal is a likely candidate for your problems. The DVR Diagnostics page in your TiVo will tell you which QAM modulation you have -- I think 256 is more common.

    The TiVo support pages have some other pages of interest that you can search for. Also searching this forum will help. I would be inclined to pressure your cable co to increase the signal strength but if you decide to try an amplifier, search the forum as users have reported experience with several models.

    I have no idea why this started happening when it wasn't before, although maybe moisture from the rain? BTW does your splitter have a matched load on the unused output tap(s)? This is important. The cable technicians should be able to provide that -- not an expensive item.

    Good luck, and welcome to the forum.

    EDIT: This just says pretty much what bkdtv's post said. We cross-posted.
     
  10. Aug 6, 2009 #1270 of 1597
    brianlaudio

    brianlaudio New Member

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    Aug 5, 2009
    Thanks, gentlemen, for the info. I, too, think my problem is low/sick signal. I'm still puzzled about why things worked so well for several months with equally low signal. Perhaps error rate has gone up. Will need to collect more (irrefutable) data.
     
  11. HLLee

    HLLee New Member

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    Aug 20, 2009
    Hi, I'm new to this board. Just found out about it searching around the web. I picked up my HD Tivo during the recent father's day promotion and have been overall very happy with it.

    Recently, I noticed that on HD recordings there are annoying white streaks on dark objects such as black suits or night scenes. These are not the typical pixelations caused by poor reception but white parallel lines. I have an over-the-air antenna as the source to the Tivo. The problem does not show up all of the time, just once in awhile. Has anyone on this board come across this problem? I did a quick search for white streaks on the forum but wasn't able to find anything. Thanks in advance for any thoughts or suggestions.
     
  12. turn_it_down!

    turn_it_down! New Member

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    Sep 25, 2008
    I've reached the end of my rope with Tivo. I'm about to throw in the towel...

    I have two Tivos hooked to Cablevision cable (an S3 and a Tivo HD). The S3 is not connected to a TA yet (the first one I got was DOA) and the Tivo HD has a TA. When I first installed the adapter, everything was lovely. Cablevision just installed new wire from my apartment to the building switch room and I was getting 95-100 signal strength on most channels and everything was coming in as clear as a bell on both Tivos.
    After about 3 weeks of bliss, the Tivo HD showed total pixelation (full screen) ON ALL CHANNELS. It is unusable and unwatchable. I've check the Error Count on the diagnostics page and it pretty much stays at zero. I tried adding attenuators to the system, as well as disconnecting the TA from the mix. In both cases the pixelation remains. From reading the diagnostics page, it seems like the Tivo can't lock in on a channel. BTW - through all of this, the S3 has continued to work flawlessly. I've had the S3 about 4 years, and the TivoHD about 2.

    I'm about to just sell out and get the Cablevision DVR. This is too much effort for something that is still basically just TV. I'm frustrated, and I'm sick of people pointing the finger at the other guy instead of trying to help me.

    Does anyone have any ideas on what the problem could be?
     
  13. rsharpe

    rsharpe New Member

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    Feb 19, 2008
    Here we go .... searched the forums but I can not find anyone with my same issues circumstances.

    I have a series 3 HD and currently am on the Cablevision system in the 07480 West Milford, NJ area. I had bought my Tivo back in 07 but never had a chance to install it. It was purchased to use on a projector which is still sitting in my basement in the unfinished movie room. Anyhow the CRT in the family room finally blew up so we went out and purchased a 50in Pany plasma and out came the Tivo from the box. I have a series 2 which works pretty good.

    Now for the fun. They come out to install the NDS cable card and everything appears to be working. After they leave I take a look at 736 -ESPNHD which is freezing and macroblocking every couple of seconds. I flip up to the next channel 737 - TNTHD and see that it is totally macroblocking 100&#37; of the time.

    I call Cablevision who comes out with a new CC (after coming out 2 times previous checking the signal) and low and behold nothing changes. After the manager+tech from Cablevision sit on the phone for 1.5 hours working on this with Tivo they decide this Tivo is bad. Mind you the tech attenuated the signal on these 2 channels up and down with no change. Tivo was nice enough to charge me $85 to replace the tivo even though it was never hooked up till now. Apparently the warranty starts when you buy the thing at the store. Total BS in my opinion but its better then the $249 they initially quoted me.

    Hooray the new Tivo arrives. I hook it up and before I can activate the CC notice 736 is working. However I did not watch it for more then 10-15 seconds. After activating the CC I look and everything is the same as it was before macroblocking fun.

    I again call Cablevision and Tivo. They of course each blame each other. The Tivo service rep went as far as to say Cablevision is purposely sabotaging the CC so I use their DVR. I decided that I could not take him very serious after going through the CC menu diagnostics he had told me one of the tables was wrong. He claimed it was wrong because the time which is in GMT was off by 4 hours. Since EST is -5+1DLS and he did not seem to grasp this I felt it was time to move on.

    Meanwhile (many visits in between) Cablevision comes out and has the balls to say, "I know you don't want to hear this but; Your tivo is not compatible with our hardware". I honestly think these techs really believe this he seemed very sincere. I responded by asking him why do other Tivos work with cablevision in other regions? He said they have had 15 more calls after my initial call with the same problems on 736+737 and Tivo refuses to fix it.

    Cablevision is again scheduled to come out tomorrow though I am not sure what will be accomplished.

    I must also mention that no matter what channel is being watched. I get random drop outs of sound. At least 1 per hour usually more. Sometimes the video freezes when that happens.

    Here is what I pulled off the Tivo.

    736 - ESPN HD
    QAM 256 369000 KHZ
    Signal Strength 93-100
    SNR 36db

    737 - TNT HD
    QAM 256 465000 KHZ
    Signal Strength 93-100
    SNR 35db

    Now for the kicker .... if I attenuate those channels at all I lose this channel.

    786 G4
    QAM 256 759000KHZ
    Signal Strength 45
    SNR 29

    Why and how can I have such a strong signal on the first 2 and so weak on the 3rd?

    If anyone has any ideas at all I would appreciate some feedback.
     
  14. dlfl

    dlfl Cranky old novice

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    The previous 2 posts illustrate what I think is the biggest problem with TiVo. If you have A/V glitches after the Cable Co. does what it can do and TiVo does what it can do (including exchanging your box), you are stuck in the middle. If you can't live with it, your only practical choice is to sell the TiVo.

    BTW, I think there are many people living with borderline acceptable performance, including myself -- see this thread for example. This is particularly rancorous to those who have had analog TiVo's that were relatively trouble-free.

    The digital video architecture used with TiVo's (CABLECards and Tuning Adapters) is more complex than the analog video system (e.g., S2 TiVos) and judging from posts in this forum (and again my experience) is more trouble prone. And it is very difficult to diagnose what causes the tough problems, i.e., those that aren't fixed by exchanging the TiVo or several cable co. truck rolls.

    The cable companies are not very motivated to make TiVo's work because a TiVo customer will make them less money (no VOD). CABLECards and Tuning Adapters are forced on them by law and only a tiny percentage of their customers use them. TiVo simply doesn't have the resources to do the sophisticated on-site diagnosis required to resolve the tough cases. Fact is these cases can be caused either by TiVo tuner and software deficiencies or by cable company equipment problems, or a combination of both.

    Solutions will have to involve a mechanism that allows cable providers to profit from TiVo installations so they have an incentive to take complete ownership of making TiVo's work well. Also, diagnosis of tough problems needs attention, which may involve more costs for technicians and equipment and also may require TiVo enhancements. Ultimately the consumer pays the cost of this, of course.
     
  15. rsharpe

    rsharpe New Member

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    Feb 19, 2008
    Adding to this the tech who was extremely ignorant of anything tivo related and not even up on the channel switch in the 700s to the 800s for premium channels came today. Needless to say he did not want to be there and did nothing to help. However I noted something very interesting. When the CC was unbound to try and reauth for the 800s I was still getting 736 and 737. Now the interesting part is that the macroblocking was completely gone. I mean those 2 channels worked perfectly though my 800s were still out. After they reauth the CC the 800s were still out and the 736-737 were still good. The tech leaves and just for the hell of it I reboot the tivo. Guess what now I have my 800s but my 736-737 are right back to macroblocking.


    Any ideas?
     
  16. turn_it_down!

    turn_it_down! New Member

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    Sep 25, 2008
    Quick Update:
    I figured since I was getting pixelation on all channels (when using Cablevision), I decided to try my ailing Tivo HD with an antenna. Well it turns out the pixelation problem still exist with OTA channels. I'm guessing that means there's a problem with the Tivo tuner, not my cable signal.
    Seeing that I'm at least a year past warranty, now I'm faced with the decision of ditching Tivo altogether or upping another $299 for to go on this merry-go-round. I'll keep you posted...
     
  17. bkdtv

    bkdtv New Member

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    Jan 9, 2003
    DC Metro Area
    When you see this pixelization problem with OTA, are there massive RS Uncorrected errors on your DVR Diagnostics screen under Messages & Settings -> System Information? If you see pixelization without millions of RS Uncorrected errors, then you've almost certainly got a defective/dying hard drive. In that case, you might spend $50-$100 to replace it using the instructions in the Drive Upgrade FAQ.
     
  18. dlfl

    dlfl Cranky old novice

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    I'm seeing occasional pixelation and other A/V glitches with zero or very little uncorrected error counts. The frequency of glitches does depend on the type of channel. Cable versions of OTA: almost never, and SDV are worse than non-SDV. The glitch rate averaged over all channels is probably 1 or 2 per hour, with the worst case maybe 20 per hour.

    The fact that glitch rate varies with channel type this way seems to eliminate the hard drive as the cause -- do you agree? (Also my THD is only 3 mos. old, although that doesn't guarantee the hard drive is OK.)

    So now my big question: Do glitches with zero error counts absolutely (or let's say with 99% probability) indicate the glitches were encoded into the signal, rather than introduced by a problem with the distribution system (e.g., cabling or connections)? In other words, do you believe these error counts really mean what they are supposed to?
     
  19. bkdtv

    bkdtv New Member

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    Jan 9, 2003
    DC Metro Area
    On off-air channels, all glitches caused to cabling, connections, and reception show up as RS Uncorrected errors. If there aren't errors, the glitches on off-air channels are always attributable to (a) the encoding on the channel, or (b) a failing hard drive.

    On non-SDV digital cable channels, all glitches caused to cabling and connections show up as RS Uncorrected errors. If there aren't errors, the glitches on non-SDV channels are always attributable to (a) the encoding on the channel, (b) a failing hard drive, or (c) a faulty CableCard. People do seem to report far more issues, percentage wise, with NDS CableCards than those from Motorola and Scientific Atlanta.

    SDV introduces another factor into the equation, for which no useful diagnostic exists. With SDV, you can get glitches without any RS Uncorrected errors and without any issue with your hard drive. It's not clear to me who is at fault for this, nor is it clear whether cabling/connections are a contributing factor. No providers offer SDV in my area, so I have no way to test with the TiVo.
     
  20. turn_it_down!

    turn_it_down! New Member

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    Sep 25, 2008
    @bddtv:
    So you think it could be the hard drive? As I mentioned in the earlier post, my RS error count was consistently less than 4 (cable and OTA) and I am seeing massive pixelation (all the time, every channel). Sometimes I could get a channel to lock in if I ran the Signal Strength meter, but it didn't work all the time.

    Wouldn't a bum hard drive effect how the Tivo performs on the Home screen, menus and such?
    Is there anyway to confirm it's the HD?

    Thanks for the feedback...
     

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