What is the animorphic squeeze trick?

Discussion in 'Archived Threads 2001-2004' started by Wil_J, Aug 30, 2001.

  1. Wil_J

    Wil_J Stunt Coordinator

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    What is it? What does it do? What is it for? Why is it better?
    I don't know what this thing is, and would like to start learning.
    I am a little bit of a newbie to everything still, especially when it comes to T.V.'s.
    One more question, when setting the black level on my T.V. using V.E., which calibration pic do I use? The one with the two black lines on the left, and the white/gray bars on the right? Or the other one?
    Any help is appriceiated........Wil
    P.S. I apologize it this has been asked before, but the search function is off right now.
    ------------------
    "The rose petal floats on water,
    the kingfisher flashes above the pond.
    Life and beauty swirl in the midst of death."

    al'Lan Mandragoran,
    *******The Wheel of Time
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    On your computer monitor you probably have a control labeled "height" or with a screen shaped figure with a double arrow up and down in it. When you adjust this control the picture becomes taller or squished down.
    This is the "vertical squeeze trick" or "anamorphic squeeze trick" everybody talks about.
    The purpose is to put all 480 scan lines, all 480 lines of vertical resolution, into a 16:9 shape to get the maximum sharpness of anamorphic (16:9 enhanced) DVD's. This is the definition of 16:9 mode on a 4:3 TV.
    A 16:9 enhanced DVD is one in which the picture is meant to be stretched out over a 16:9 shaped space when viewed, there is no intrinsic difference in the picture material itself, although there is data (flags) additional to the pictre that dvd players and some TV sets use to automatically adjust processing and/or picture shape for you,
    Unfortunately relatively few TV sets can do it with front mounted controls or service menus, although most sets have screwdriver adjustments in back which may do it. Of those sets which can do it, for some it is not easy to change back and forth to 4:3 mode. Sometimes the convergence goes bad or you get bowed lines or other geometric problems when you try it.
    If your TV cannot do the squeeze trick, you will have to set 4:3 mode on the DVD player. On anamorphic dvds the player will then digest the video giving the same shape letterboxed picture but now some resolution is lost. (Without doing the squeeze, 360 of the 480 picture carrying scan lines occupy the biggest 16:9 shaped space fitting the screen. One out of every four lines of picture information is dropped or blended causing the picture to occupy those 360 scan lines in the middle, and synthetic black bars put at top and bottom.)
    About black level, it is your choice which pattern you use, but the best pattern has two black bars on a nearly black background, you adjust it so the darker of the black bars just merges with the background. I think it is AVIA that has one such pattern having a lot of bright area elsewhere on the screen, another is mostly dark. If you get different settings with the two patterns, that means your TV is not as good holding the black level when there is bright material elsehere on the screen (inherent usually uncorrectible shortcoming) and you should use a compromise setting.
    If you use a pattern with ten or so equally sized large stripes ranging from white to black, do not merge the two blackest stripes but instead all stripes should be distinguishable.
    Other video hints: http://members.aol.com/ajaynejr/video.htm
    .
    [Edited last by Allan Jayne on August 31, 2001 at 09:29 PM]
     
  3. Wil_J

    Wil_J Stunt Coordinator

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    Ummm....Ok. That did help a little bit, but it isn't quite coming clear for me. Anyone else?......Wil
    ------------------
    "The rose petal floats on water,
    the kingfisher flashes above the pond.
    Life and beauty swirl in the midst of death."

    al'Lan Mandragoran,
    *******The Wheel of Time
    [Edited last by Wil_J on August 30, 2001 at 06:46 PM]
     
  4. ThomasL

    ThomasL Supporting Actor

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  5. Paul T

    Paul T Auditioning

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    I have been thinking of trying to make the anamorphic squeeze automatic, but i am not quite sure how to do the switching part. I know that pin 8 of the scart lead controls what ratio the dvd picture is in (6 volts for 16:9 or 12 volts for 4:3), so i was thinking that i could use a relay to switch between the on-board height potentiometer (set for 4:3 viewing) and an off-board height potentiometer (set for 16:9 viewing). This would mean cutting the tracks on the circuit board going to and from the height pot to isolate it and then wired to the relay so that it can be switched between one or the other pot. There are (at least?) two problems: first, the current from pin 8 on the scart lead is about 30-40 milliamps but the only relay that i have at the moment requires at least 70 milliamps to work, and secondly: because the voltage for 4:3 viewing is 12 and 16:9 is 6 i would need a relay that only works below approx 10 volts (so if it went above 10 volts it would switch back to the on-board 4:3 pot) otherwise it would always be set to 16:9.
    The other way to do it would be to set the on-board height pot to 16:9 viewing and the off-board pot for 4:3 and use a relay that only works above approx 8 volts. The problem with that is because the dvd player only outputs a voltage on pin 8 when it is turned on (not in standby mode) then normal tv viewing would always be in the squashed 16:9 mode. The other other way would be to use two relays and two off-board pots (one set for 4:3 and the other set for 16:9), so that when ANY voltage is detected at pin 8 of the scart lead the first relay disconnects the on-board 4:3 pot and then depending on the voltage the second relay switches between the two off-board pots (maybe using a relay that only works above approx 8 volts). But then i`ve got the problem of limited scart current operating two relays. The other other other way would be to use transistors to do the switching , but i have no idea whatsoever how transistors work. Can you buy low current, input voltage limited, high voltage (150v+) switching relays?
    Of course there is still the small problem of gaining access to the underside of the tv circuit board to cut and solder.
    If none of this makes sense to anyone, just put it down to the ravings of a deranged (but ambitious) mind, but any ideas, suggestions or dissuasion would be welcome.
     

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