why overscan???

Discussion in 'Archived Threads 2001-2004' started by Aaron Cohen, Oct 14, 2002.

  1. Aaron Cohen

    Aaron Cohen Second Unit

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    I have a question about overscan? Is it the tv or the dvd player doing it? I have a widescreen television and am just starting to notice the little bit of overscan.... why would they have done this? I would rather have teeny black bars than to miss part of the picture!
     
  2. Aaron Cohen

    Aaron Cohen Second Unit

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    Anyone know why? This isn't just me experiencing this is it??
     
  3. Kevin P

    Kevin P Screenwriter

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    Overscan is a "feature" of the TV, intended to hide undesirable artifacts such as geometry issues at the extreme edges of the screen, as well as some of the extraneous information carried on the video signal, such as blanking, closed captioning, macrovision, etc.

    It is possible to build a TV set that has no overscan (front projectors and computer monitors are often designed this way) but it would increase the cost of the TV beyond what most people would want to pay for it.

    KJP
     
  4. Aaron Cohen

    Aaron Cohen Second Unit

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    Thanks for the response. Is this only with widescreen tv's though? If for instance I put my Silence Of The Lambs dvd (which is 1:85:1) in a standard 4:3 tv, would I have more picture at the top and bottom of my tv than I would be seeing on my widescreen television?
     
  5. Lew Crippen

    Lew Crippen Executive Producer

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    It is possible to reduce the amount of overscan. You can have your set calibrated by a qualified technican, or use one of the disks such as AVIA as a tool. Before you start on this project yourself, you should be aware that changing some of the configuration values is not a project to embark upon lightly. If you do, and choose to enter into the service mode, write all values down first. This way, if you make a mistake you can at least get back to where you were.

    Write all values down first.

    You did not say, but if you have a rear projection TV, if might well be worth your while to have the set calibrated by a qualified technican.
     
  6. Ming Wang

    Ming Wang Agent

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    overscan presents on all TV sets. you don't want a TV with no overscan.
     
  7. Rain

    Rain Producer

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  8. Steve Schaffer

    Steve Schaffer Producer

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    Overscan is your friend as long as it's not excessive. Not all sources are perfectly centered on the screen--some dvd players come with an adjustment to move the picture a bit to center it but most don't.

    I'm as fanatic about OAR as anyone, but not to the point that I'd rather risk wierd stuff at the edge of the screen than tolerate 3-5% overscan.
     
  9. Bill Slack

    Bill Slack Supporting Actor

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    Rain:

    CC, macrovision, etc are all present on DVDs too.

    If you want a set that you can get the minimal overscan as possible, get a fixed pixel display. You can get most CRT based sets down to 2.5% on each side though.

    Remember that even projected film effectively has overscan. The image almost always spills over onto the mattes, even in places that know what they're doing.
     
  10. Rain

    Rain Producer

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    I'd rather have weird stuff at the edge than overscan.

    I'm not about to buy a different TV. I just bought a brand new Sony RPTV.

    Projected film is an entirely different ballgame. That's not really overscan.

    Even the titles and such are slightly cropped off on some films due to overscan.
     
  11. Bill Slack

    Bill Slack Supporting Actor

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    Sounds like you have more than a little overscan, Rain. With about 2.5% things should be perfect, since films (almost) never go to the very edge.

    It's not very difficult to make these adjustments in the service menu, on your own. Just need to change the height and width params with some Avia test signals up and then straighten out the green geometry/convergence grid (using a string) and then converge red/blue to green.

    You Sony is actually be optimal for this. For all the service menu settings, you must write them in order to have the settings be permanent after a power cycle. Assuming that this also applies to convergence, you wouldn't have to worry about screwing anything up in your learning process (though check on that first!)

    Some DVD players (my Toshiba 6200, for one) allows you to zoom in/out to get no overscan and no picture anomalies. Though on my player, at least it's to coarse to do it without black bars on all sides.

    I certainly understand your frustration though. I wish the sets were made with the most minimal amount (trust me, you really don't want to see the CC info, it's about 3-4 lines of analog noise and very distracting.)

    An ISF tech (like you're looking for...) could obviously help you out here too. Michael Chen (TLV) is excellent. Both he and Gregg Loewen have tweaked my set (along with my own hack-ish attempts...)

    An interesting note... some DVDs actually compensate for overscan on TVs (Blade Runner, I know) but not very many.
     
  12. Steve Schaffer

    Steve Schaffer Producer

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    Rain,

    I've got last year's version of your set in a different screen size and have never seen any indication of cropping of titles or anything.

    If you could post some of the dvd titles you've observed this on so I can try them on my set, as well as whether they're anamorphic and what aspect ratio setting you're using maybe I can duplicate it on mine.
     
  13. Rain

    Rain Producer

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  14. Steve Schaffer

    Steve Schaffer Producer

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    Thanks Rain, I don't have either of those but now I have an excuse to get Women on the Verge--I am a huge Almadovar (sp?) fan anyway!
     

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