Adjusting image size & position with AVIA : what is "safe action area"?

Discussion in 'Archived Threads 2001-2004' started by JasonRH, Jul 13, 2001.

  1. JasonRH

    JasonRH Second Unit

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    Just going through some calibrations with my Wega and Avia disc and noticed the geometry and convergence patterns have lines called "safe action" area markers that they say help in setting image size and position. Are these lines supposed to be visible on all edges of a correctly adjusted picture? Currently mine are not. Thanks.
     
  2. Andrew W

    Andrew W Supporting Actor

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    Yes, safe action and safe title should be fully visible.
    The total overscan top, bottom left and right should be adjusted to be less than 5% You may not want to do this yourself if you don't know how.
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    Andrew in Austin
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  3. ThomasL

    ThomasL Supporting Actor

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    Jason, such adjustments will need to be done in the tv's service menu. Be warned that changing the raster size can also affect geometry and convergence. On a 27 inch set I have, I have a little more overscan on the left hand side - perhaps 6 percent. WID (width) service adjustment doesn't do anything on my tv unfortunately so my only recourse was to tick HPOS (horizontal position) to shift the screen over a little bit to the left. When I did this, I noticed that convergence errors popped up on the upper left hand side. I decided, since the set seemed to have very good convergence everywhere, that it wasn't worth it.
    btw, for anyone who has ST II on DVD, a great non-Avia/VE scene to test your convergence occurs at 12 minutes into the movie. It is the initial scene where the Reliant is shown flying through space. In the background are a lot of little twinkling stars. On a set with great convergence, all the stars should be twinkling white. On my Toshiba 27A40, this is true...I looked at the same scene on a Sharp tv and it looked like all the varied lights of a Christmas tree.
    cheers,
    --tom
     
  4. JasonRH

    JasonRH Second Unit

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    Andrew and Thomas,
    Thanks for the replies. Does it matter if the lines indicating "safe action area" are slightly past the edge of the screen? I already see convergence errors at the bottom left and bottom right and if raise the image vertically or shrink horizontally to have all lines visible I think the convergence errors will be worse. Is performance affected by not having all safe action area indicators in view (other than having more overscan than you want, of course)?
    Thomas,
    I have ST II and I'll check your suggested sequence. Thanks.
     
  5. ThomasL

    ThomasL Supporting Actor

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    Jason, when you say slightly past the screen, do you mean, you can't see them? I wouldn't worry too much about it. Your tv had its overscan set at the factory and performance shouldn't be affected whether or not your overscan is a little higher than the 5 percent (e.g. 5 1/2 percent). The only thing it does affect is how much of the image you see. And on letterboxed dvds, you're only losing image real estate on the sides.
    cheers,
    --tom
     
  6. JasonRH

    JasonRH Second Unit

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    Thomas,
    Yeah, I mean the safe action area lines are past the edge of the screen because overscan is over 5% on the lower portions of the screen. I didn't think it made a difference but the term "safe action area" implies it may be detrimental to not have image size and position set correctly. Funny term to use.
     
  7. ThomasL

    ThomasL Supporting Actor

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    Jason, by safe action area, I believe they're referring to those markers being inside the visible area, as in, your overscan is below 5 percent and thus you may see some distortion, convergence problems, among other things (i.e. stuff in the actual transmitted signal that no one normally sees). How low one can go with overscan, without introducing more problems than it is worth, really depends on the manufacture and type of set, I would assume. It seems that 5 percent is the standard that manufacturers aim for.
    cheers,
    --tom
     
  8. Jim Ferguson

    Jim Ferguson Stunt Coordinator

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    The "safe" in "safe action" doesn't refer to what's safe for the TV set. It's an instruction to the director of the TV show (or movie) as to how close to the edge of the frame he or she can put crucial objects, or "action" to be sure that it will be seen on even the most overscanned display devices.
     

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