blocks of white flicker at the bottom

Discussion in 'TiVo Series 1 - UK' started by jonmon, Oct 8, 2011.

  1. Oct 8, 2011 #1 of 24
    jonmon

    jonmon New Member

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    Jan 19, 2010
    Hi there :)
    Got a 1 Tb drive in my tivo from tivo central. Pleased with all that space. I have a bit of a prob though, there is some times blocks of white that flicker at the bottom of the screen:(. Has anyone else had this prob? think it mainly happens on BBC 2, I am watching itv now and it seems ok, also i was watching bbc 1 and that seems to be ok as well:). I know its not the freeview reception as it does not do it when I press the aux button it doe not do it.
    Any help would be appreciated
    thanks:D
     
  2. Oct 8, 2011 #2 of 24
    jonmon

    jonmon New Member

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    Jan 19, 2010
    I have found out that this is common on mode0 setting, so I am guessing I have mode0 on the drive. Does anyone know if I can turn off using the remote?
    Also is it ok to use a digital signal booster on the arial for getting a better reception, when the tivo is analogue, I think? Does anyone use a digital signal booster on there tivo?
    thanks:)
     
  3. Oct 9, 2011 #3 of 24
    steveroe

    steveroe Must do some work...

    1,136
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    Oct 29, 2002
    Oxford, UK
  4. jonmon

    jonmon New Member

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    Jan 19, 2010
    ok thanks
    :D
     
  5. drgeoff

    drgeoff Member

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    Nov 10, 2005
    A "digital signal booster" is an invention of marketing people not engineers. Ditto "digital aerials". The same amplifiers and aerials can be used for for analogue and digital. But what aspect of your reception needs to be bettered? An aerial amplifier can help in some situations but is not a panacea for all ills.

    The Thomson/Tivo TiVo (as opposed to the Virgin/TiVo TiVo) is indeed an analogue device. It takes its input signal(s) from either or both of its aerial input and the Aux SCART. That SCART, if used, would be connected to a Set Top Box such as a Sky Digibox or Freeview box, but almost invariably a "digital" box of some kind.
     
  6. michael401

    michael401 Member

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    May 20, 2011
    It's a simplification but with digital you either get a signal or you don't. You only need an amplifier if you cannot currently get a signal at all but you said Freeview is alright on its own so that isn't your problem.
     
  7. jonmon

    jonmon New Member

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    Jan 19, 2010
    thanks for both replies
    I get a better understanding now. I have taken the booster of. As I get a picture when using freeview, so what you have told me would be no benefit. A norther reason I took it off is because I think it was effecting the picture quality permanently. Is it possible that the signal booster can effect the picture quality permanently. I was thinking, because the tivo is analogue and the booster is digital it might effect it. But what your saying that there is no difference between digital and analogue signal boosters, so it cant be that thats coursed the picture quality to be effected.

    Also there is something else about the picture, going back to the white flashes, it think its got worse as now I get black flashes even green and this seem to happen quite a lot and on every channel. Does this sound like mode0 is coursing this? I know its not the signal quality of the arial. I think I am going to have turn mode0 off as I am a bit fussy about this sort of thing as you probably guess. I dont really want to take mode0 off as it does seem to make a difference.
    thanks:)
     
  8. AMc

    AMc Active Member

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    Mar 22, 2002
    East of England
    It sounds like Mode0 is overloading the video encoder and it's nothing to do with the signal. That's probably the reason Tivo didn't enable it officially.

    If you have Tivoweb then you may be able to lower the settings to get the artefacts under control if not then try Steveroe's suggestion.
     
  9. jonmon

    jonmon New Member

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    Jan 19, 2010
    Ok thanks
    You say you might be able to lower the settings for mode0 in tivoweb, I have tivoweb, you dont know how this is done do you? I cant see anything that might do that in tivoweb.
    thanks:)
     
  10. DX30

    DX30 New Member

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    May 22, 2005
    Use "Resource Editor". Under "Resource Groups" you'll see "Bitrates". You could try reducing the "DBSBestVBRBitrate" and "DBSBestMAXBitrate" settings and see if that makes a difference. You'll need to restart the TiVo after changing the settings.

    The changes the settings for Best quality. You can also try different settings for High, Medium and Basic qualities (the naming is obvious). You can also change "DBSBestResolution" back to 4 if you cannot get satisfactory results with mode 0.
     
  11. steveroe

    steveroe Must do some work...

    1,136
    5
    Oct 29, 2002
    Oxford, UK
    The "DBS" set of resources are for a sattelite source, as the OP has mentioned aerial boosters then I suspect we're talking a Freeview source here in which case look for the CATVBestMAXBitrate (and CATVBestVBRBitrate if you have VBR enabled) rather than the DBS equivalents.

    Alter one value, then press enter. Go back the menu and alter the other if needed, press enter again. Now click the "update resources" link and reboot the Tivo.

    There is a long thread about Mode 0 here: http://www.tivocommunity.com/tivo-vb/showthread.php?t=286938&highlight=mode+guide which was given to you in a previous thread you posted requeting help, have you read it?
     
  12. jonmon

    jonmon New Member

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    Jan 19, 2010
    Hi thanks for the info:up:
    I am using freeview but hoping to get freesat soon. If I need to change different setting for ether one of them then I will wait till I get freesat before I change anything. I have read the link you gave me and understand a bit more about this flashing lines and blocks of white ect. but also says that changing the bit rate does not necessary make any difference. Have to what and see I guess. Does anyone know if it gets worse or better using a different sores like freeview to freesat?
    Thanks:)
     
  13. RichardJH

    RichardJH New Member

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    Oct 7, 2002
    Hanworth....
    FWIW I always found it worse on BBC channels on Freeview. Virgin cable didn't suffer as much. Never have had Sky or Freesat so no help there.

    After a while the white flashes were ignored as the picture quality was much better in mode0
     
  14. jonmon

    jonmon New Member

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    Jan 19, 2010
    Ok, so it might be a bit better on freesat, will find out soon. I will report back when I have it. Your wright about the picture quality is much better and I can put ip with the white flashes at the bottom of the screen every so often. But some times there is green blocks that flash up, and noticed it cant seem to cope with low quality images like on a cheap video like VHS grainy images. When that happens the flashes are very consistent. Does anyone know why that is the case. Also I notice some times it does it when the screen is totally black screen or totally white. That to me seems strange as there is not much information being shown so I thought that would be easer to handle. anyway I might be able to forget about the flashes, if not I will try changing the bit rate or go back to mode 4
    thanks:)
     
  15. Ian_m

    Ian_m Active Member

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    Jan 9, 2001
    Southampton,...
    If I remember way back, when my mate was involved in the design of UK TiVo (as technical rep for Sony MPEG encoder) it is due to "datarate" overload of the IBM MPEG decoder chip, which is why mode 0 was dropped from released product.

    Pictures of all the chips.
    http://www.9thtee.com/InsideTiVo.htm

    I think this is right, as if you get the media files direct from the TiVo there is no white flash in the MPEG file, this being produced by the IBM MPEG decoder.

    Yes a poorer quality (ie VHS) and a higher quality source will require a higher MPEG data rate so therefore suffer from white flashes.
     
  16. SNJpage1

    SNJpage1 Well-Known Member TCF Club

    4,517
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    May 25, 2006
    Atlantic...
    I thought the bits of light at the bottom was a result of over scan and what you are seeing is digital information that is usually hidden from sight.
     
  17. drgeoff

    drgeoff Member

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    Nov 10, 2005
    No.

    1. Anything you would see at top or bottom that is usually hidden from sight would be exposed by under scan.

    2. The digital info that is sometimes seen is invariably at the top of the screen.

    3. In this case the white flashes only occur when Mode 0 is operating.

    The explanation given by Ian_m fits the facts and is believable.
     
  18. jonmon

    jonmon New Member

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    Jan 19, 2010
    Hi:)
    I am using freesat now and want to make sure that I am changing the bitrate correctly. There seems to be no right numbers to put in, but can anyone tell me what would be a good figure to start with for VBRBitrate and MAXBitrate? Also I wanted to make sure I use the write setting for freesat, is it CATVBestMAXBitrate? Also it is mentioned about changing mode back to 4. Do I put in 4 where it shows 0 in DBS best resolution? If that is the case does live TV get shown in mode 4?
    Thanks for any help:)
     
  19. johala_reewi

    johala_reewi New Member

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    Oct 30, 2002
    Southampton UK
    See also steveroe's post above...

    The "DBS" set of resources are for a satellite source.
    The "CATV" set of resources are for a Cable or TV source.
     
  20. jonmon

    jonmon New Member

    116
    0
    Jan 19, 2010
    Hi there
    Thanks for the info, but I have decided to disable mode0 as I cant stand the flicker and pix-elation that show up. I could disable mode0 with kick start, so it was nice and easy to do. The picture quality though is much worse now but I think I can live with that more than the flashes. I did find even with out mode0 there were some flashes very occasionally so it makes me think that mode0 cant be to good for the decoder chip.
    There was something else I would like to know, I am getting a humax foxsat receiver and that can show in high definition. So am I wright in saying that I can plug the humax into the tivo using scart and it will record in SD and at the same time have the hdmi lead in the tv for HD? Also do you have the humax setting for the resolution at 1080p for HD even though the humax needs to be in sd for the tivo?
    thanks for any help:)
     

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