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Tivo HD Pixelation Troubleshooting

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

  1. Nov 13, 2007 #381 of 1597
    fergie8

    fergie8 TiVoite via RCN

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    Oct 26, 2006
    Chicago, IL
    I have that problem on my new TiVo HD, however my cable company is RCN.

    So, what constitutes too hot a signal in terms of the data I can read on my tivo's Diagnostics screen?

    Channels that are causing intermittent pixelization problems for me have signal strengths in the range of 87-93 with occasional peaks up to 100. The signal to noise ratio (SNR) display for those channels sits around 35-36 dB. Might those values be considered too high? If so, what range of values should I be trying to hit when I start adding attenuation?

    Any advice on this would be greatly appreciated. Thanks.
     
  2. Nov 13, 2007 #382 of 1597
    SCSIRAID

    SCSIRAID Active Member

    2,321
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    Feb 2, 2003
    Vero Beach, FL

    The peaks to 100 would be what would concern me. The final arbitor as to when its 'right' would be the RS Uncorrected value staying at zero and no visable pixelation. Given the peaks to 100, I would suggest attenuating 3 to 6 db and see what happens. 'Typical wisdom' would be to look for stable mid 80 to mid 90's signal strength with SNR around 34db. Note that typical wisdom can be wrong so its just a starting point. FiOS is one proof point of this.
     
  3. Nov 13, 2007 #383 of 1597
    AbMagFab

    AbMagFab What happened, TiVo?

    3,638
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    Feb 5, 2001
    The magic SNR for FIOS is 31/32. Not sure if that would also work for other "hot" cable connections, but it's worth a try, as it's easy to test.
     
  4. Nov 16, 2007 #384 of 1597
    PaulRuby

    PaulRuby New Member

    22
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    Jul 27, 2005
    My experience, in case it helps anyone...

    Two Tivo S3 on Comcast in Sacramento. Pixelation started on one Tivo about two months ago and has gotten progressively worse. The other tivo is fine. Finally, watching Sunday Night Football was unbearable. And, I was starting to get some pixelation on downloaded content (tivocast). So, I figured it must be the HDD. However, I checked signal strength on ESPN-HD and it was a little low (SNR 29-30, Signal 63-69). I decided to upgrade the hard drive to see if that would help anyway. Went from a Seagate barracuda 750gb to seagate barracuda 1TB. All pixelation is gone. And here's the annoying thing. The signal strength now shows perfect on all channels. This seems an incredible coincidence. I checked just before and just after changing the HDD and signal went from marginal to perfect. I'm pretty much convinced my HDD was the primary issue but I don't understand the signal strength wierdness.

    Key thing: the HDD might be the problem for more folks than we might think, even if the signal strength looks a bit marginal.
     
  5. Nov 16, 2007 #385 of 1597
    bkdtv

    bkdtv New Member

    7,902
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    Jan 9, 2003
    DC Metro Area
    Sounds like your previous drive upgrade caused some sort of interference.
     
  6. Nov 16, 2007 #386 of 1597
    PaulRuby

    PaulRuby New Member

    22
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    Jul 27, 2005
    Yes it does... But it took a year to go bad. Was great for ~8 months then spent 4 months getting to the unbearable point. Now is great again with the 1TB drive. I sprung for the more expensive 24-7 version of the drive (NS instead of AS suffix) so I hope that means it'll survive longer than a year.
     
  7. Nov 17, 2007 #387 of 1597
    Berone

    Berone New Member

    108
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    Feb 14, 2005
    My FIOS installation to a new S3 went flawlessly. I followed instructions from another thread to walk the installer through the process. Unfortunately I only verified that I had signal - I didn't check for pixelezation. Later in the day I started seeing the problem and started testing things. It was bad - on almost all channels, but worst on the HD channels. On the worst channels the signal bounced from 100 to 72 to 0 and all around that. The SNR bounced from 32 to 38, and the RS uncorrected was rising constantly. As I was unwilling to use FIOS without Tivo I only have 15 days to fix it or dump it. Calling FIOS tech support yielded the "we don't support Tivo" response. Trying to find attenuators locally was a flop and I didn't have time to order online. Fortunately I occasionally work for CBS and a tech at the broadcast center hooked me up. I got two 10 db and two 6 db attenuators from him, and there was already a 3 db that the installer used. The CBS tech told me that if I used 20 db of attenuation I wouldn't get any signal at all. So I followed the directions above - first 16 db and then working down to 6 db. The best was at 16, but there was still pixellezation. So I went up to 20 db. The tech I spoke to was wrong. While the signal still jumps around from the low 70's to 90 and the SNR jumps from 31 to 35, the RS uncorrected is 0. I'll continue to test it over the next few days, but now it looks good. The best part is the message I got from Verizon tonight making sure that everything went well after the installation. Yeah, you can bet I'll be returning that call! Thanks, bkdtv, for posting this information - happy to have the new service and Tivo!
     
  8. Nov 17, 2007 #388 of 1597
    kpepling

    kpepling New Member

    21
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    May 10, 2004
    I installed my attenuators and I was able to lower my SNR but no matter what I do it will not stay stable. It jumps around from 31-32 and I still get some pixelization. I don't have any real drop outs just some issues where the picture gets messy but not the sound. That is using 16db and when I tried 20db I got an unstable picture.
     
  9. Nov 17, 2007 #389 of 1597
    bkdtv

    bkdtv New Member

    7,902
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    Jan 9, 2003
    DC Metro Area
    You might need more or less attenuation. You'll rarely get the right amount on the first try.

    There is a 3-4dB range that will eliminate pixelization. Too much attenuation will give you a weak signal, too little attenuation won't resolve the problem on all channels.

    You might try 18dB and 14dB.
     
  10. Nov 19, 2007 #390 of 1597
    rlintacoma

    rlintacoma New Member

    6
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    Sep 30, 2007
    I was really concerned about the pixelation problem which was particularly bad on one or two channels and by some HD channels which mysteriously disappeared last week.

    Poking around on this thread, it seems lots of people have the problem and are having mixed results getting it fixed. I guess I am one of the lucky ones and both problems were fixed with a short visit from the Comcast tech.

    My cable ran from the wall through my rather expensive surge protector and then into TIVO. It has done this since I first got an HD TV and when I used Comcast's crappy Motorola cable box/DVR. But the pixelation problem began about a month ago. The tech took the cable out of the surge protector and put high end connectors on the cable. My pixelation is gone. And my missing channels came back as well. His explanation: the surge protector was causing the pixelation problems and the better connectors fixed the missing channels. I don't know if he knows what he is talking about or not, but my problems went away.
     
  11. Nov 19, 2007 #391 of 1597
    kpepling

    kpepling New Member

    21
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    May 10, 2004
    I've tried 13db, 15db, 16db, 18db, 19db, & 20db. None of those have worked. I can't seem to find either 2db or 1db attenuators to be able to test 14db & 17db. Anyone know where I might find one or is willing to sell me one?
     
  12. Nov 19, 2007 #392 of 1597
    bkdtv

    bkdtv New Member

    7,902
    0
    Jan 9, 2003
    DC Metro Area
    The attenuator pack I linked includes 2x -20dB, 2x -10dB, 2x -6dB, and 2x -2dB attenuators for $12.99.

    Edit: It includes 2x -3dB attenuators, not 2x -2dB attenuators.
     
  13. Nov 20, 2007 #393 of 1597
    kpepling

    kpepling New Member

    21
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    May 10, 2004
    I bought that pack and it includes 2x 3db attenuators not 2db.
     
  14. Nov 20, 2007 #394 of 1597
    bkdtv

    bkdtv New Member

    7,902
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    Jan 9, 2003
    DC Metro Area
    Ooops, thanks.
     
  15. Nov 20, 2007 #395 of 1597
    SMB-IL

    SMB-IL Member

    39
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    Mar 5, 2003
    Chicago, IL
    I told a friend of mine who has had TiVo since it first came out about my sudden pixellating problems on the S3 and although he doesn't have any contact with online forums and is just an average TiVo user, told me to delete programs from my Recently Deleted list and the pixel problems would go away. I was highly skeptical after reading here, but I did and it worked. Shows recorded before I permanently deleted Recently Deleted are pixelled and shows recorded after are not. I'm planning to upgrade the HDD, but I thought maybe this might help someone else in the meantime. My signal strengths are in the 65-75 bracket both before and after.

    Maybe TiVo needs to consider telling the system where to write data because it seems as though some of the problem might be that the drive is being written to the same spot all the time? I don't know, but opening the system up to using other areas of the drive really solved my problem for the time being.

    Happy Turkey Day everyone!!
     
  16. Nov 20, 2007 #396 of 1597
    richsadams

    richsadams Active Member

    8,893
    2
    Jan 4, 2003
    The Recently Deleted folder seemed to be an issue back in May/June when we were first adding expansion drives to the S3's. There were reports of slowdowns and other problems when the RD folder filled up. This was with v8.1x and v8.3x. Some suggested that the partition /var(?) that is used to index the RD files was too small to handle the "extra volume" at the time.

    I found that keeping the RD folder empty made everything run normally but that when I let it fill up (200+ recordings) TiVo became sluggish and unresponsive at some points.

    Since receiving v9.2.j and subsequently v9.2a I'm letting the RD folder fill up again based on the premise that with eSATA support TiVo could/should have modified the software to handle the additional indexing "load". I haven't seen any slow-downs or other problems but the RD folder is only up to about 62 recordings so far. I do see the odd and very brief macroblocking or audio drop now and then but nothing unexpected w/HD broadcasts.

    It would be interesting if deleting everything in the RD folder helps anyone else that has macroblocking or other problems.

    BTW, since there isn't a "delete all" option for the RD folder, the fastest way to clear it out is to open the folder, highlight a recording and click the "clear" (TiVo remote bottom left) then "select" buttons.
     
  17. Nov 21, 2007 #397 of 1597
    thenorthman

    thenorthman New Member

    6
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    Sep 30, 2007
    Well kind of aggravating but in the same breath can not complain to much.

    Since an upgrade that allowed us to be able to transfer shows between our two Series 3 HD boxes I am now getting pixel problems on the "downstairs" HD box.

    Which means, in theory, that it has something to do with TIVO rather than my cable company since it was immediately after the upgrade.

    Any suggestions?

    Sean
     
  18. Nov 21, 2007 #398 of 1597
    gjlloyd

    gjlloyd New Member

    2
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    Oct 15, 2007
    just got my 2 cable cards installed in ashburn, VA. new HDTIVO ( from amazon for $250!)

    it went well and the tech was very cool. he joked several times about 'giving us one more chance before you switch to tivo' :)

    no pixelation so far.
     
  19. Nov 24, 2007 #399 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    15
    Oct 19, 2000
    No. VA/D.C.
    Had mine done Wed. here in Sterling/Cascades....getting some blocking, espec. on Food Network. I'm at 36db...ordering some attenuators
     
  20. Nov 24, 2007 #400 of 1597
    dslunceford

    dslunceford Active Member

    5,712
    15
    Oct 19, 2000
    No. VA/D.C.
    OK, here's the weird thing....watching 144, Food Network. No issues with blocking *UNTIL* there's a button press from the TiVo remote. Right on Dpad, volume, FF, whatever, it starts the pic blocking. Will taking down the db to 0 or -6 help with this issue?
     

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