Pixel question on Plasma TVs

Discussion in 'Displays' started by Stan, Dec 25, 2004.

  1. Stan

    Stan Producer

    May 18, 1999
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    I'm beginning to look into getting a widescreen HDTV, probably plasma.

    I recently received a catalog from Dell that had what looked like a very nice HD ready 42 inch set.

    Please excuse my ignorance, but what is exactly meant by the pixels being 1024x768? I have a 19 inch monitor set at 1024x768 and it has wonderful resolution, but I can't imagine this being expanded onto a 42 inch screen. Is the Dell system using this same resolution on a screen that is more than four times the surface area of my 19 inch?

    Wouldn't that end up being pretty grainy and jaggy looking with really large pixels?

    If this is a stupid question, please don't slam me, I just want to become more educated on the subject.

  2. SimiA

    SimiA Second Unit

    Jul 26, 2004
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    1024x768 is an XGA resolution that is consindered HD.
    It should display a 720p signal quite well, or 1080i for that matter.
    Your PQ will be excellent with an HD signal, or DVD.
    I'd want to see how well it could handle an SD signal.
  3. Mark Larson

    Mark Larson Supporting Actor

    Mar 3, 2002
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  4. Allan Jayne

    Allan Jayne Cinematographer

    Nov 1, 1998
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    Compared with on the computer monitor, you may notice some jagginess on the 42" TV simply because you have the same number of pixels spread out over a larger area.

    720p has 720 scan lines (requiring at least 720 rows of pixels for best results) each scan line divided into 1280 parts. To use all 768 rows of pixels on the screen some scan lines of source material are repeated and/or blended. If the 1280 pixels of source material on a given scan line have to share 1024 pixels across on the TV the blending isn't too bad.

    1080i HDTV has scan lines divided into 1920 parts each, almost like having two side by side pixels of source sharing one pixel (of the 1024 across) of your TV screen. By sharing I mean, if a red pixel and a blue pixel of source want to end up on a spot on the screen represented by one screen pixel, the screen pixel will not be half red and half blue* but rather will be all one color, generally a blend of the two source pixel colors. You have lost half the horizontal resolution but the picture is still stunning. Vertically there are 1080 scan lines of source that have to share 720 rows of pixels on the screen, unfortunately the quality loss can vary widely depending on the TV's circuitry. In some cases only 540 unique lines or spots of source detail vertically might be measurable if you had a test pattern (I don't know of any HDTV test patterns).

    But note that DVD and other NTSC standard definition material has just 480 scan lines (or rows of pixels). Assuming good upscaling circuitry inside, your 42" TV with 768 rows of pixels will give a smoother DVD or SDTV broadcast picture than a regular 42" TV including plasmas with 480 rows.

    Video hints:

    * (for gurus only) Actually on a plasma screen each screen pixel is 1/3 red, 1/3 green and 1/3 blue but the colors within the screen pixel are always in the same order regardless of whether the blue source pixel came first and the red source pixel sharing the same screen pixel came second or vice versa.
  5. Mort Corey

    Mort Corey Supporting Actor

    Nov 21, 2003
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    Another factor to consider is that you won't be sitting as close to a television as you are to a computer monitor. (Well, at least I wouldn't) The input source and the TV's scaler will make all the difference on how well SDTV is displayed.


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