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Thread: Svideo to VGA/DVI without picture improvement(for e.g. for Atari)?

  1. #1

    Default Svideo to VGA/DVI without picture improvement(for e.g. for Atari)?

    Hi and thank You for answering in advance
    Are there some adapters, that can help connecting Atari to e.g. LCD screens with VGA or DVI input?
    Currently I have a Compro Videomate V150, and Avermedia DVI Box. Sadly - both probably improves image when connecting using Svideo or Composite. I don't known how to turn improving off.
    I am also using Comprovideomate with my Atari 65XE via RF cable...

  2. #2

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    The S-video source runs at 480 or 576 lines. So how are you going to avoid scaling?

  3. #3
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    Quote Originally Posted by mcs_5 View Post
    The S-video source runs at 480 or 576 lines. So how are you going to avoid scaling?
    S-Video is an analog signal and has no hard defined resolution standard. Case and point, the Atari 65XE has a resolution of 320x192, which can be much less when accounting for overscan. S-Video certainly can't pass a full NTSC signal through it without significant degradation because there isn't enough bandwidth available. It is far better than VHS can reproduce, as well as composite video, but nowhere near component video or pure RGB.

    Besides using a CRT monitor, there's not going to be any good solution to get an unmolested video signal out of the console. The closest I can think of is by using an old analog capture card on a PC and displaying the output, but this introduces significant amounts of latency. And really, who wants to see a postage stamp video signal of 320x192 on a huge monitor?

    The PC is going to be the cheapest solution, but there are advanced scan doublers made specifically for old game consoles that have a lot of configuration options, just be prepared to shell out some cash because they get expensive the more features they offer.

  4. #4

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    Quote Originally Posted by GiGaBiTe View Post
    S-Video is an analog signal and has no hard defined resolution standard.
    That's true only of horizontal pixels per line, the vertical resolution is still determined by the timing of the v sync pulse (i.e. the number of lines per frame/field)

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    Quote Originally Posted by maxtherabbit View Post
    That's true only of horizontal pixels per line, the vertical resolution is still determined by the timing of the v sync pulse (i.e. the number of lines per frame/field)
    And? It's still not a defined standard, which is why a CRT monitor can work at weird resolutions that no modern LCD can tolerate. Case and point, again, the Atari 65XE 320x192 resolution; It's miles off from the standard 525 line NTSC resolution.

    Analog signals were heavily abused by basically everything for any reason. Convenience, cheapness, laziness; it didn't matter.

    Monitors had to do a fair bit of interpretation on signals to get an image, and even then it was not perfect. This is why old CRT monitors had tons of adjustment controls for the geometry, focus and V/H hold.

  6. #6

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    Quote Originally Posted by GiGaBiTe View Post
    And? It's still not a defined standard
    It certainly is a defined standard. The (US-standard) TV has to receive something close to 525 lines per frame and 60 frames per second - otherwise it won't sync. The actual resolution doesn't have to be 480 lines, but the TV still has to receive the correct number of lines to work. Don't spread nonsense please...

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    Quote Originally Posted by mcs_5 View Post
    It certainly is a defined standard. The (US-standard)
    The analog signal going through S-Video is NOT a defined standard. S-Video has a theoretical bandwidth limit of around 4 MHz, that's it. You can literally toss any analog signal on an S-Video cable, and it was done.

    Quote Originally Posted by mcs_5 View Post
    TV has to receive something close to 525 lines per frame and 60 frames per second - otherwise it won't sync.
    No, it doesn't. If old CRT televisions worked how you said, then images from game consoles, VCRs, DVD players, etc. would all be squashed at the top left of the screen.

    Yet another example would be that VCRs had 240 lines total (for NTSC.) How did it fill up the entire screen then? It fudged the timings so 240 lines would sync to the entire screen, exactly what everyone else did.

    The Sega Genesis fudged the timings so that only the front porch was rendered, effectively turning an interlaced CRT into a progressive scan display. This is an other example of how analog signals were abused to achieve a specific effect.

    Quote Originally Posted by mcs_5 View Post
    The actual resolution doesn't have to be 480 lines, but the TV still has to receive the correct number of lines to work. Don't spread nonsense please...
    Except it's not nonsense, it's how it worked.

  8. #8

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    Quote Originally Posted by GiGaBiTe View Post
    Except it's not nonsense, it's how it worked.
    Please do your homework. Using a scope if needed...

    A VCR does output 480 lines - it just displays the same line twice. Computers do something similar. You cannot get the correct line frequency, without transmitting the correct number of lines. It's very simple actually...

  9. #9

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    Quote Originally Posted by GiGaBiTe View Post
    S-Video certainly can't pass a full NTSC signal through it without significant degradation because there isn't enough bandwidth available. It is far better than VHS can reproduce, as well as composite video, but nowhere near component video or pure RGB.
    Broadcast TV is composite video. So yes, you can (easily) pass full resolution SD video through composite or S-video.

  10. #10

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    You guys are both missing something very important - the distinction between fields and frames. NTSC is 262 or 263 total lines (240 active) per *field* which is why progressive computer sources with low line counts still meet timing.

    Really helps your understanding of analog video if you start looking at some timing tables and learn about blanking intervals etc.

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