4:3 tv's and the anamorphic squeeze

Discussion in 'Archived Threads 2001-2004' started by TimHON, Mar 12, 2003.

  1. TimHON

    TimHON Agent

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    Could someone tell me if something is wrong with my Toshiba 36HF72. I have my dvd player set to output 16:9 signal and the tv set to compression mode. This should do the anamorphic squeeze I have read about and it seems to accomplish this to a point. The picture does indeed look great and I can tell there is a difference between the compression setting and letterbox. My question is regarding the black matting at the top and bottom of the screen. There are actually two shades. The dark black at the very top and bottom which does not change when brighness is adjusted and a dark grey portion closer to both sides of the picture. This only seems to happen in DVD's which are formatted at the 2:35:1 ratio. For example I put in Forgiven last night and noticed this. If I watch a 1.85:1 dvd I this doesn't happen. Of course the black matted portions are much smaller. Does the Toshiba only compress the the 16:9 ratio? Is this true of all 4:3 sets that do the squeeze. I have to admit to being a little confused.
     
  2. Patrick Sun

    Patrick Sun Studio Mogul

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    In compression mode, the TV compresses the display to mimic the 1.78:1 aspect ratio (AR). This is a fixed compression ratio due to the 16x9 spec (which is a 1.78:1 AR). This results in very solid black bars because the TV doesn't send any video content to these 2 areas in the compression mode.

    When you have wider AR content, like 2.35:1, there will still be black bars on the top and bottom of the displayed video because the width is constant, so the height has to be reduced to produce the 2.35:1 aspect ratio.

    When playing a film with a 2.35:1 AR The 2 types of black bars are from:

    1. The 16x9 compression
    2. The other black bars built into the video display to play back the correct 2.35:1 AR on a 16x9 set.

    The differences in blackness of the bars comes from the display area having the black level too bright.
     
  3. TimHON

    TimHON Agent

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    Thanks. I have calibrated the set using Sound and Vision disc but not with the DVD player set to 16:9 and the Toshiba set to compression. Should I redo the calibration with these settings? Is the S and V disc enhanced for 16:9 TV's?
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    The black top and bottom area prerecorded on disk and inside an imagined 16:9 frame after squeezing may or may not be true black. If you want to calibrate the TV so this black area matches the area closest to the screen top and bottom devoid of scan lines, that is your preference. This may make the calibration for everything else slightly wrong.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  5. Jack Briggs

    Jack Briggs Executive Producer

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    Yet I would contend you're slightly overdriving the set. The interior bands should blend seamlessly with the unused area of the screen.

    This is variant of the "I have a 16:9 TV yet I still see black bars"-type question. Whenever you screen a film that's wider than 1.78:1 or 1.85:1, it will have to be letterboxed within the 1.78:1 frame.
     
  6. jeff lam

    jeff lam Screenwriter

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    The only way to mask the two shades and have proper calibration is to use mattes or have more room light. No display can produce true black that the dead space is when calibrated to the proper level using the VE or Avia brightness. In a dark or black room, you can't get the brightness low enough to blend the two sets of bars and still have a good bright picture. Maybe an ISF calibration would help, a DVD player with 0 IRE black level output will also help.
     
  7. Jason F.

    Jason F. Stunt Coordinator

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    I'm going to hijack this thread...I have a 32 inch Sony that has the enhanced mode. The only thing that I don't like about it is that it makes the 16:9 picture even smaller, is that normal?
     
  8. Patrick Sun

    Patrick Sun Studio Mogul

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    You mean, people look short and squatty? Maybe you'll need to set your DVD player to output 16x9, not 4:3 (which enables the downconversion capability of the DVD player, and that would squash the video height-wise, which would make the video's height smaller/shorter ).
     
  9. Brent Hutto

    Brent Hutto Supporting Actor

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    If a TV is doing the "real squeeze", like the 36HF72, there will be a difference in calibration depending on squeezed or unsqueezed. On my Sony 36XBR800 I compared the two modes after doing an Avia calibration (unsqueezed) and decided the difference was not worth worrying about. There is a difference, though, since you're squeezing the same number of lines of electron-beam scanning into a smaller space. One day I'll probably recalibrate in squeezed mode since that's where most of our viewing is done but the difference really is minor (like two clicks each on the white and black level settings).
     
  10. Michael St. Clair

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    You always want to do the calibration in squeezed mode. On some sets the difference is more than a click or two. Regardless, if you calibrate in 4:3 then watch in 16:9, you are overdriving the set.
     

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