Video cuts out during big changes in picture

Discussion in 'TiVo Series3 HDTV DVRs' started by kraquen, Sep 18, 2007.

  1. kraquen

    kraquen New Member

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    Jan 28, 2002

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    For the last few weeks I've been having a problem with my hd tivo: when watching HD channels whenever there's a sudden large change in the video, the entire video will become scrambled and go black and then return to normal about 3 seconds later.

    At first I thought this problem was the new component video switcher that I put between the tivo and my tv, but then I noticed that if I rewind the tivo and go through those frames slowly that i can freeze frame on the distortion. My xbox 360 and hd-dvd player do not have this issue, and they go through the same component video switch (psyclone from best buy).

    Has anyone else experienced this problem?

    Thanks,
    Jason
     
  2. CCourtney

    CCourtney Member

    489
    2
    Mar 28, 2006
    El Dorado...
    Go to the diagnostic menu and see what the signal strength is. If it's really high then it may be overpowering the tuner.

    Signal Strenght of channel you're watching?
    What's the source Antenna or Cable?
    Is it amplified?

    CCourtney
     
  3. kraquen

    kraquen New Member

    16
    0
    Jan 28, 2002
    I have 1 coax coming into the back of my tivo from the cable with 2 cable cards.


    There's no amplifier in my line, I do have a splitter and a cable modem on the same line. I checked my signal strength in the diagnostics menu and it shows 97.

    Thanks,
    Jason
     
  4. CCourtney

    CCourtney Member

    489
    2
    Mar 28, 2006
    El Dorado...
    I think it may be overwhelming the tuner. When you get radical changes in picture you have in spike in data being transmitted over a short period of time, which can potentially saturate the input to tuner beyond what it can handle. You're almost peaked out on the signal strength w/ 97.

    You may want to put either an attenuator (or extra splitter) in between the splitter and TiVo to take the signal strength down some and see if it helps.

    CCourtney
     
  5. kraquen

    kraquen New Member

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    Jan 28, 2002

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    thanks, i'll try that!
     
  6. PopcornGuy

    PopcornGuy New Member

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    Apr 6, 2007
    Orlando, FL
    Wait a minute...A high signal strength is bad?
    I have a signal booster on the cable line in and yes there are sometimes problems in fast moving scenes. There will be "pixelation" on just the moving object. So what is the ideal signal strength? Everything I've read says a low signal is the cause of this type of problem.
     
  7. CCourtney

    CCourtney Member

    489
    2
    Mar 28, 2006
    El Dorado...
    I don't know what the ideal strength is as far as the Tuner in TiVo HD goes. But all tuner's will have an ideal strength band (Too low, loss of signal -> Data loss) (Too high, saturation of signal -> Data loss/potential put tuner into a failsafe mode after which it resets.)

    I'm seeing most of my channels for Digital Cable in the upper 60's, and my antenna in the mid 80's. I have seen some pixelation on certain stations when the signal strength dropped down to 58-62 range.

    FWIW, I also boost my signal w/ a 15dB amp (and have everything off an 8 way splitter afterwords 11.5dB attenuation) -> +3.5dB > feed into the house. Based on this I'd guess that many people in my neighborhood w/o the amp would have signal strength issues and hit the pixelation range.

    I don't know the spec on the TiVo HD but most tuner's have a dBmv spec range with a min dBmv and a max dBmv that they will support and the max-min is usually ~20-30dB.

    That said, I have know idea what the TiVo HD reports as signal strength. It's not in dBmv's.
    I would assume that a signal strength of 100 is close to if not the max signal strength it can handle.

    CCourtney
     
  8. kraquen

    kraquen New Member

    16
    0
    Jan 28, 2002
    What I'm seeing is not pixelation.. the entire image cuts out. The audio is unaffected. The image looks as if you unplugged the coax from the tivo, then my tv reports "no signal" for a few frames afterwards. Then the image comes back.

    I was watching Aliens in HD. This is a very dark movie, whenever someone would use a flamethrower and the entire screen goes from dark to bright it happens.

    Thanks,
    Jason
     
  9. davel77

    davel77 New Member

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    0
    Feb 15, 2008
    I am having this same exact problem. If I plug the Tivo HD directly into the TV, I have no issues, but if I go through the switchbox, the video drops out on big video changes. I know its not the switchbox because I've tried two of them. I have called Tivo, but they are no help.

    I would not think it would be the signal strength. That reflects the signal from the cable company, not the signal strength going from the tivo HD through the component cables to the TV.

    Any help would be greatly appreciated.
     
  10. kraquen

    kraquen New Member

    16
    0
    Jan 28, 2002
    it turns out that the switch was the problem. I now use my old video only switch for video and the psyclone switch for audio only.
    No problems.
     
  11. davel77

    davel77 New Member

    3
    0
    Feb 15, 2008
    Which switch are you using? I bought a second one that didn't work and want to find one that someone has confirmed that is working.

    Thanks.
     
  12. kraquen

    kraquen New Member

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    Jan 28, 2002
    The psyclone component / spdif is the one that cuts out... works great for audio.. works fine for my dvd player and my xbox 360 on video.. but sucks for my tivo (btw i run tivo in 720p).

    The good video switch does video only..

    Inday RGB4x-R 4x1 Wideband Component Video Switch

    Doesn't look all that great.. but i can't tell _any_ difference between the picture direct or through the switch.

    My tv is a dlp projector 720p on a 120" screen.

    Good luck..
     

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