Overscan - surely its in the source equipment?

Discussion in 'Archived Threads 2001-2004' started by Mark ZA, Mar 19, 2003.

  1. Mark ZA

    Mark ZA Agent

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    Greetings,

    Recently made the foray into burning my own DVDs and I have some overscan questions. I copied all my footage from my DV camera to my PC and then burnt it to a DVD-R. When I watch this DVD-R using the PC, all of the image is visible on the screen...when I transfer this disc into my DVD player however, it is severely overscanned...to the point that most of the captions I put on (that the software told me was in the 'safe' area) are off the screen :-

    This led me to think that it is the DVD Player that is overscanning because all of the PCs image is visible on the TV screen.

    Anyway, I'm gonna re-render all my footage and add an overscan region all around it. Thank the maker for DVD-RW.

    If anybody has any input I'd love to hear it.

    Mark
     
  2. Jeff Kleist

    Jeff Kleist Executive Producer

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  3. Guy Kuo

    Guy Kuo Supporting Actor

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    Most of the image lost off the edges is due to overscan in your television. Most consumer sets have at least 5% overscan. However, you are technically right in that a small number of pixels are lost within the DVD player due to "pixel cropping." Pixel cropping is needed to keep the pixel rate at spec but still keep within the allowed NTSC active line time. Pixel Cropping in the DVD player is a very tiny amount of image loss compared to that hidden by overscan in the display.
     
  4. Mark ZA

    Mark ZA Agent

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    Just a follow-up - why then is there no overscan whatsoever on the output from my PC to the TV?
     
  5. ManW_TheUncool

    ManW_TheUncool Producer

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    Maybe your TV-out hardware/software is shrinking the image to offset TV overscan. If it's any good, it should at least allow you the option to do this so that the entire PC desktop can be displayed on the TV.

    Check to see if that's what's happening and see how much offset it's doing.

    _Man_
     
  6. Guy Kuo

    Guy Kuo Supporting Actor

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    Exactly, many PCs when outputing an NTSC signal do a window boxing prior to feeding out the signal. That brings everything to inside the TV screen despite overscan on the TV. That is the opposite of what you were suspecting. The DVD player's signal is closer to normal, standard NTSC window framing.
     
  7. LaMarcus

    LaMarcus Screenwriter

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    Guy Kuo has spoken!!
     
  8. Mark ZA

    Mark ZA Agent

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    Aaahh, yes - it all makes sense now. Thanks for the input :[​IMG]
     
  9. Tom Wilson

    Tom Wilson Auditioning

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    Try ripping a dvd to your hard drive, then play from there and from your dvd player at the same time. Pick the same frame and freeze it and switch back and forth and you'll see how much overscan there is on the dvd player/tv. I was surprised.
     
  10. LaMarcus

    LaMarcus Screenwriter

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    A simpler way I found out how much overscan was on my display when watching dvds is I just zoomed out with the remote control and it showed me what I was missing. If you do this with video essentials dvd on the overscan screen it will show you the percentage and if your picture is not centered.

    Mine was off center a little bit and my overscan was at 10%!! I went into the service menu and changed all that.[​IMG]
     
  11. ManW_TheUncool

    ManW_TheUncool Producer

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    Btw, I heard that VE's overscan pattern is wrong, so don't go by VE for this. [​IMG]

    _Man_
     
  12. LaMarcus

    LaMarcus Screenwriter

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    Ah shit, don't tell me that.
     
  13. Guy Kuo

    Guy Kuo Supporting Actor

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    Sorry to confirm it. The VE Overscan pattern is a little off center in the video frame. If you center your image and overscan adjustments using that pattern, your display ends up showing everything else a little off center. I rather doubt you will be so far off that it would bother most viewers. Just don't use the display to judge how well your own video productions are centered.
     
  14. LaMarcus

    LaMarcus Screenwriter

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    Jeez man....Now I have to get your disc Guy. Essentially I wanted the Avia disc any way ( I just didn't want to pay $50). I found the VE disc for $17 so I went with that.
     
  15. Guy Kuo

    Guy Kuo Supporting Actor

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    LaMarcus, while I'd certainly like you to go get a copy, I'd do it only if you were already going to get it. This non-centered issue isn't big enough in itself to do it. What AVIA will get you is access to next generation patterns for more adjustments but those are largely in the domain of professionals and very advanced amateur tweakers. Although, the AVIA video and audio tests are quite a bit more advanced, for the casual user, VE should be sufficient. Trying to use the advanced sections of AVIA forces you to learn considerably more about how your video and audio system works. (BTW, you should be able to find AVIA for quite a bit less than MSRP if you look a bit harder)
     
  16. Jim Doolittle

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    Hi Guy and all,

    The Overscan test pattern on VE is indeed off center. This occurred on many of the geometry test patterns that are on that disc. Title 20, chapter 5, the anamorphic test grid, is centered correctly in both the horizontal and vertical planes, but the circles aren't perfectly round. I usually use AVIA to put the final touches on geometry.

    The upcoming DVE will be MPEG perfect, and you will be able to get a consumer copy for $25.00. We are hopeful for a June release.
     
  17. LaMarcus

    LaMarcus Screenwriter

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    Cool![​IMG]
     

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