Random hack/Mini project thread

Discussion in 'Showroom' started by DanielHall, May 24, 2010.

  1. TheInvisibleSun

    TheInvisibleSun Visible Member

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    Buffalo, NY, USA
    Yes, unless you are near a signpost or at a boss. It does something a bit...different during Sky Chase.
     
    Last edited: Jun 10, 2021
  2. badnest

    badnest Newcomer Trialist

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    Dec 3, 2019
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    This is not entirely true. NTSC signals (and PAL-M, for that matter) are made up of 525 interlaced lines. Some of those are used for blanking and whatelse, but there's still 480 lines left for video.

    What happens is that analog TVs don't have pixels, they just draw scanlines from left to right at whichever point on the screen they want to, basically (contrary to popular belief, scanlines are the drawn lines, not the black lines inbetween). Depending on power fluctuations, those scanlines could be drawn further or closer apart from each other, resulting in increased or decreased vertical picture size. To prevent you from seeing the end of the picture if the height temporarily decreased slightly, TV manufactures calibrated the sets so only around 448 lines were seen onscreen, while the rest is drawn outside of the CRT's visible area (overscan).

    Console manufacturers used a technique that, to simplify, turned the 480 lines at 60 half frames per second video signal into 240 lines at 60 full frames per second. But since only 224 lines would be visible on most TVs, most video games consoles up to the 2000s only had an active video resolution of 224/448 lines because anything more would be a waste of resources.

    If you manually decrease the width on a NTSC TV, you'd see the overscanned lines without any problem back when 4:3 TV broadcasts were a thing. I believe you'd also see a Mega Drive drawing all the 240 lines, but it only draws a single color on the other lines besides the main 224. Kinda like how it normally looks on a PAL system/TV.
     
    Last edited: Jun 10, 2021