how to deal with overscan

Discussion in 'Displays' started by PeterK, Oct 5, 2004.

  1. PeterK

    PeterK Supporting Actor

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    I got my new widescreen tv (hitachi 51F500) I put in DVE and low and behold, the horizontal overscan is about 5% and the vertical is 7.5% I though the whole idea of widescreen tvs was to fix aspect ratio problems like this. I put in finding nemo which is anamorphic so it should fill the whole screen. There are parts of it missing. I can chech this by switching from 16:9 to 4:3 mode on the tv so even though it is squished I can still see that picture on the edge is missing. I can't tell vertically because because changing the tv's aspects doesn't do anything but stretch and zoom in. Is there a way to deal with this overscan? I don't think there is anything in the users menues but I could be mistaken so if anyone has my tv it would be great if you knew. If I can't do anything myself what can I do. I doubt my parents would pay for someone to come and correct it because they really wouldn't notice a difference if it was 25% overscanned and losing 1/4 of the picture!
    thanks.
     
  2. ChrisWiggles

    ChrisWiggles Producer

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    Some overscan is normal on most TVs, but if you'd like to minimize it, it is usually a service menu adjustment, etc.

    I'm not familiar with your display, but hopefully someone will know better how to access the service menu, etc.

    Overscan helps hide information and "junk" that can sometimes crop up at the extreme edges of movies that are distracting. A slight amount of overscan is usually desired, though often TVs use too much.
     
  3. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    the image sizing (over scan) on Hitachi crt sets is adjusted by turning 2 pots on the board.

    If you take it down too far (< 5%) the magic focus will not work. After adjusting the sizing you will also have to reinitialize the magic focus after redoing the convergence. Also the edges will have less accurate convergence if taken down.

    Best of luck (and call a service tech unless you want to void your warranty).

    Regards

    Gregg
     
  4. PeterK

    PeterK Supporting Actor

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    What are pots and where is the board?
     
  5. PeterK

    PeterK Supporting Actor

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    Am I correct to assume that a projector does not have problems with overscan and will show the ENTIRE picture?
    Just one more reason to get a projector.
     
  6. Scott L

    Scott L Producer

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    This can be a double-edged sword because for digital cable TV I see all this noisy jitter on the very top 2 lines of resolution. Good thing is many projectors have an overscan feature where you can crop off a little bit of the all sides, though it's too much on mine (a 4805).

    I have to admit though no overscan works great for DVDs.
     
  7. ChrisWiggles

    ChrisWiggles Producer

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    Overscan is not a design "problem" per se. A little bit is desired to avoid seeing the junk at the edges of the image. The problem is just when it's too much lost, you'd want to reduce that.
     

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