Burn in and Squeeze questions

Discussion in 'Archived Threads 2001-2004' started by Steve_Tk, May 6, 2002.

  1. Steve_Tk

    Steve_Tk Cinematographer

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    Sorry I'm new at all this.

    Burn in: If I buy a 4:3 TV, and I only watch widescreen movies, will I get burn in on a digital TV. On my TV now I always watch movies and have not noticed a problem, but my contrast and brightness are pretty low.

    Squeeze: I think I know what squeeze is on 16:9 tvs. it's where they squeeze the 4:3 picture to make it 16:9 and may look a little distorted. But what is squeeze on 4:3? Is it where people watch widescreen movies but use a "squeeze" and it fills the whole picture so you don't see black bars? wouldn't the people look very skinny and tall?

    My DVD player is just run into the video port on my tv. When I watch a movie I don't have to adjust anything, the black bars just vary in size according to however wide the "widescreen" is. CAn't you just do this with any 4"3 tv?

    And why do you need a progresive scan DVD player? Why is squeeze always associated with anamorphic DVD's

    Sorry for so many questions.

    If burn in is really just a problem with Rear projection then what kind of TV do you buy that's not rear projection.
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    You have to be careful about burn-in with RPTV and FPTV more because the ratio of the CRT square inches to the screen square inches is so much greater compared with direct view (1:1). The CRT's in projection TV have to emit lots more light to get the same amount of light per square inch on the screen. The amount of energy involved with projection TV is so great that the lenses mounted on the CRT faces contain cooling liquid. It is the heat that builds up in the process of making enough light to put on the screen that literally burns the phosphors and the glue that holds them on the face of the CRT.
    If for projection TV you can keep the contrast under 1/3 you should get reasonably long life from the set.
    Everything in this post applies equally to progressive scan and regular interlaced video.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  3. Yohan Pamudji

    Yohan Pamudji Second Unit

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    By varying the settings on a squeeze-capable 4:3 set (e.g. Sony Wegas) and your DVD player you get these results. A couple assumptions here: 1) anamorphic DVDs, 2) when the TV set's squeeze is "on" it is forced to squeeze as opposed to auto-detect. Hopefully my descriptions will make sense.

    TV: no squeeze

    DVD: 4:3

    picture: correct aspect ratio

    resolution: not maximum

    TV: no squeeze

    DVD: 16:9

    picture: people look tall and skinny

    resolution: maximum

    TV: squeeze

    DVD: 4:3

    picture: people look short and wide

    resolution: not maximum

    TV: squeeze

    DVD: 16:9

    picture: correct aspect ratio

    resolution: maximum

    As you can see to get the best out of your anamorphic DVDs on a 4:3 TV set you should set the TV set to do the squeeze and set the DVD player to output in 16:9 ratio. This way the DVD player outputs the maximum resolution it can resolve to the TV set and the TV set displays it correctly by using the squeeze. This isn't an exhaustive explanation so feel free to ask more.

    Oh, and as far as using the term "squeeze", for the process of making a 4:3 image fill an entire 16:9 screen I like to use the term "stretch" instead, because it stretches the image horizontally thus making people look short and wide. The squeeze on 4:3 sets does a vertical squeeze, which adjusts the original image which had tall and skinny people making them look normal.
     
  4. Steve_Tk

    Steve_Tk Cinematographer

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    Thanks for the help

    though I'm still confused on the squeeze

    "TV: no squeeze

    DVD: 16:9

    picture: people look tall and skinny

    resolution: maximum"

    Why would the people look tall and skinny? On my DVD player now when it plays wide screen the people look perfectly normal on a 4:3 TV, I just have black bars above and below them, which does not bother me.
     
  5. jeff lam

    jeff lam Screenwriter

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  6. Yohan Pamudji

    Yohan Pamudji Second Unit

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    Steve,

    Try doing this experiment by changing the setting on your DVD player. The attribute is called different things on different players, but it should be something like "Picture Output" or something. Yours right now should be set at something like "4:3 letterbox". Set it to "16:9" and see what happens to the picture when you watch anamorphic DVDs. The picture will be tall and skinny, most noticably the people.

    That's how anamorphic DVDs are encoded. They utilize the maximum resolution DVD has to offer. When displayed unaltered, the image on an anamorphic DVD is in 4:3 format with everything stretched vertically. When you set the DVD player to output 4:3 instead of 16:9, it does "downconversion"--essentially taking out lines of resolution to make the picture look right. When you set the DVD player to 16:9 it outputs the anamorphic (tall and skinny) image unaltered. That's where the anamorphic squeeze (for 4:3 TVs) / stretch (for 16:9 TVs) comes in. 4:3 TVs with the squeeze capability squeeze the picture vertically to make the picture look right while still using all the lines of resolution. 16:9 TVs stretch the picture horizontally to make the picture look right while still using all the lines of resolution. Hope this helps.
     

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