Interference at top of screen in SD

Discussion in 'TiVo Series3 HDTV DVRs' started by smgord, Oct 4, 2007.

  1. Oct 4, 2007 #1 of 11
    smgord

    smgord New Member

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    Aug 9, 2004
    I have a weird problem ... not sure it is actually a problem, but let's see what you all think.

    Brand new Sony XBR4. When watching through the Series 3 Tivo (and only when watching through the Tivo), there is a very think sliver of pixelation at the top of the screen, in SD programming. This mostly happens on lower numbered SD channels, but can occasionally be seen in SD programming on HD channels (i.e., a non HD program that I'm watching on the ABC HD channel).

    Changing the setting from full pixel to normal or the wide mode from full to any of the other settings but one gets rid of it -- but at the price of a more distorted picture.

    Any ideas?
     
  2. Oct 4, 2007 #2 of 11
    bkdtv

    bkdtv New Member

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    That pixel line is part of the picture signal.

    That line is usually hidden with overscan. However, if have the Sony's HDMI input set to "no overscan" mode, you are going to see those artifacts. Why don't you try the +1 format setting on the Sony?
     
  3. Oct 4, 2007 #3 of 11
    MScottC

    MScottC Well-Known Member

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    Those little dots and dashes you see running across the very top of the screen are bits of data. They can be either Closed Captioning, Timecode (a frame identifying system used in video production), or a variety of other forms of data used by the various programming networks and stations.

    I can't speak in Sony terminology, but on my Samsung, when I'm in "Just Fit" mode you see those signals. However I can switch to 16:9 and blow the image up ever so slightly, which is the way the broadcasters intend for you to watch the TV. From the beginning of TV, we in TV production always framed our images with the idea that a small outer percentage would be cut off, as it was impossible with the older sets to control exactly how the screen was scanned. Set manufacturers would always set up TVs to fill the screens and then some, cutting off the edges of TV programs. Program producers (the tech side of that group) always got away with garbage on the edges of the screen that was always in "overscanned areas." With digital production and flat panels, both ends are very much more under control, yet even on NBC HD I still see a yellow line on the left side of my screen, and I see those data lines at the top of most SD shows. If they bother you, switch to the option that blows up your image just a bit.
     
  4. Oct 4, 2007 #4 of 11
    DTG

    DTG Member

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    I have the same problem reported by the OP. I found that setting the TiVo's output to Native, or not using the HDMI cable to the TV, 'cured' this problem.

    :mad:
     
  5. Oct 4, 2007 #5 of 11
    aaronwt

    aaronwt UHD Addict

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    This info at the top of the screen is nothing new. It's been there for a long time. It's just that most TVs had over scan which hid it.
     
  6. Oct 5, 2007 #6 of 11
    smgord

    smgord New Member

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    Aug 9, 2004
    thanks, I think I've found settings I'm comfortable with now. The key was the video output setting on the tivo. The default was outputting everything at 1080i -- as DTG said, setting it to native got rid of the data issue.
     
  7. Oct 5, 2007 #7 of 11
    MScottC

    MScottC Well-Known Member

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    Perhaps then, the TiVo is not properly scaling TV signals to fill the 1080 (or 720p) screen. Perhaps TiVo needs to upres the image just a bit more. I'm wondering however if they chose an even pixel upres factor to avoid dithering. Their other option would be to place the upressed 480 image slightly higher in the screen, or crop off the top 2-3 lines of the screen. And yes, I've noticed this issue mainly on just upressed material.
     
  8. Oct 5, 2007 #8 of 11
    jsb_hburg

    jsb_hburg New Member

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    Feb 27, 2005
    Do you mean image shift? This could be done in the service menu of your hdtv. However, it might reveal "noise" at the bottom. The better solution would be user adjustable cropping that does not introduce overscan.

    Overscan or zooming of the picture reduces the resolution and picture quality of the image. I don't like overscan because I like to view the best picture possible.

    Though I do not see the noise very much on the channels I watch, it would be a good idea to be able to crop or block those offending lines without reducing the resolution and native sharpness of the picture.
     
  9. Oct 5, 2007 #9 of 11
    smgord

    smgord New Member

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    Aug 9, 2004
    Actually, due to my other settings, that is disabled. The closest thing would be to go to +1, as suggested above.
     
  10. Evilmonkee

    Evilmonkee New Member

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    Sep 7, 2007
    Yeah, on my Vizio there are H/V positioning and size settings. I had to adjust mine just enough to get rid of the data stream on all channels.
     
  11. jtown

    jtown New Member

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    Sep 26, 2002
    The Tivo's not doing anything wrong. It's displaying the entire image.

    Overscan is a CRT thing. It masks the variation in sizing and the curved edges. Similar to framing a picture with ragged or uneven edges. Some CRTs overscan as much as 10%. Since the extra lines at the top and bottom were going to waste, a small amount of data was encoded in them. As noted earlier, that can include closed captioning. Since positioning of the LCD image is absolute, there is no need to "clean up the edges" of the image. As a result, the entire image can be displayed. As a result of that, we now see those wasted lines that were given over to closed captioning and such.

    If you want to get an idea how much of the image is wasted on CRTs, make sure you're set up so you see those "noise" lines at the top of the image, then look at a news crawl or score overlay in a sporting event. Those graphics are placed so they appear right at the top and bottom edge of the screen when displayed on a CRT with a normal amount of overscan.
     

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