Is horizontal resolution affected by the type of connection used?

Discussion in 'Archived Threads 2001-2004' started by Andre Bijelic, Sep 20, 2001.

  1. Andre Bijelic

    Andre Bijelic Stunt Coordinator

    Feb 10, 2000
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    Are horizontal resolution measurements affected by the type of connection used (composite, s-video, component)? I know standard (RF) cable is limited to about 330 lines of resoltion, but can component connections really yield more detail than s-video or even component?
  2. John Coleman

    John Coleman Guest

    To answer your question simply, different cables have very different bandwidth characteristics. However, this isn't to be confused with the resolution of the source. For example, a DVD is 480 (interlaced or progressive) vertical lines. No matter what connection you use, composite, component, etc. you will always only have 480 lines. The quality of the signal will vary, but the quantity of the resolution is static (I know, this is obvious).
    However, when stepping into higher resolution source, is takes a higher bandwidth cable to keep up. For example, even though s-video and component cables can be used on the same NTSC source, component video cables are capable (through their bandwidth characteristics) of twice the resolution an s-video cable is (this is a REALLY simplified statement, though).
    Anyway, this is really simplified, but I hope it answered your questions. Please feel free to e-mail me privately with any additional questions regarding cables or connections.
    John Coleman
    Cobalt Cable
    [email protected]
  3. Allan Jayne

    Allan Jayne Cinematographer

    Nov 1, 1998
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    Horizontal resolution (number of light/dark dots each of the 480 scan lines (for NTSC) can be subdivided into and still be distinguished) is the first to suffer when the cable bandwidth is not so high.
    For program material, if presented as an NTSC 480i signal modulated onto a broadcast channel (RF) the (black on white) horizontal resolution is limited to about 330 upright lines or dots fitting across the diameter of the largest circle which in turn fits a 4:3 screen.
    Composite, S-video, and component video are limited only by the bandwidths of all the circuitry and cables, and for composite, the quality of the comb filter. Of course if the source material is not that sharp, the deficiencies of the resolution of the circuitry may not be as apparent.
    480p needs twice the bandwidth as 480i for the same horizontal resolution.
    Some bandwidth requirements: 480i DVD (540 lines of resolution @ 4:3 or 720 pixels all the way across) 6.75 MHz, 480p DVD (same resolution) 13.5 MHz, 1080i HDTV 37 MHz for all 1920 pixels across (1080 lines of resolution @ 16:9) the picture still looks good at half that resolution handled by 18 MHz; 720p HDTV 37 MHz.
    Color horizontal resolution is limited to about 50 lines for composite (a little more for some color combinations), 150 lines for S-video regardless of source, no particular limit for component video except digital sources typically have color resolution half the regular (black on white) resolution.
    Unfortunately it is not easy to tell the bandwidth of a cable without using test equipment. You just have to take the manufacturer's word for it or assume that more expensive cable is better.
    [Edited last by Allan Jayne on September 21, 2001 at 05:02 PM]

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