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Technical explanation please.......!!!

Discussion in 'Projectors, Screens & Video Processors' started by Johnny Thunder, Feb 18, 2005.

  1. Johnny Thunder

    Johnny Thunder
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    Could you please explain the following video signals.
    I would like to know a bit more about each, and also, what sources that I am likely to come across, that produce these video signals.
    1125i(1080i)
    750p(720p)
    525i(480i)
    625i(575i)
    525p(480p)
    625p(575p)

    I think I am pretty much ok with regards to interlaced and progressive, 3:2 pulldown etc.

    Thank you

    Johnny.
     
  2. KraGorn

    KraGorn
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    These define various resolutions of image, the numbers being the number of scan-lines that make up the image. The first number you show is the actual number of lines making up one full frame while the number in brackets is the number of VISIBLE lines, ie. those that make up the image itself, the rest are used in TV broadcast systems etc. to send control information, teletext etc.

    Normal usage leaves off the width of the image (expressed also as the number of columns forming a 2D array, the X coordinate), and this is inferred from the number of rows, the Y coordinate).

    Assuming 16:9 and 4:3 aspect ratios according to conventional use, these are the full resolutions:

    1920x1080
    1280x720
    all the rest are 720x (BTW, the 575 values are actually 576).

    The 'i' means interlaced, the 'p' means progressive.

    HTH. :)
     
  3. Johnny Thunder

    Johnny Thunder
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    Am I correct in assuming the first two are HD...?
    What output does Sky+ give..?
    Thank you btw Kragorn.

    Johnny.
     
  4. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    All PAL sources are 576i (ie DVD players, freeview, vcr, Sky, cable)
    All NTSC sources are 480i

    Prog scan DVD players will output these as 576p or 480p

    The 720P and 1080i stuff is HD resolution but not all sources with these outputs are HD. For instance you could get a DVD player with an HDMI 720P or 1080i upscaled output but that's not HD it's just SD scaled up to HD.

    Native HD sources may be PC's, imported D-Theatre digital tape decks, imported Blu-Ray recorders, HD cam's, HD Satellite receivers.

    Gordon
     
  5. Johnny Thunder

    Johnny Thunder
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    Thank you Gordon.
    I think I am finally starting to get to grips with all of this.

    Johnny.
     
  6. dolph

    dolph
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    Sky+ gives a normal interlaced non HD signal.

    The first two are HD (whatever that means...)
     

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