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VIDEO to VGA convertor

Comments

  • ingoingo
    edited July 2009
    It is a good picture if composite signal is the best you have from your computer. But compared with RGB to VGA converter it has lower quality even if you choose high resolution on your video to vga converter and I choose lower resolution on my RGB to vga converter.

    But for 48k Speccy without RGB interface it is a good solution.

    Greets Ingo.
  • LCDLCD
    edited July 2009
    The picture is better than from my old Joymate Video to VGA converter which I use.
  • Mister BeepMister Beep
    edited July 2009
    Hi, Vele.

    I wonder how exactly the "Mixing of two different colours is converted to static screen lines" looks like.
    I mean - could you add to the site one or two photos of GigaScreen pictures?
    (If you don't have any, I can send you several, for FatWare engine).
    ZX Spectrum 48K BEEPER Music:
    http://mister_beep.republika.pl/
  • chevchev
    edited July 2009
    I have a +2A and a Dell monitor which accepts every input except RGB/SCART. My choices are build a composite circuit (cheap and reasonably practical) or go with a converter of some desription. If have understood things correctly I'll get a better picture from RGB - component video than RGB to VGA/DisplayPort/HDMI. These converters aren't cheap though so I'll probably go with composite.
    zx.itch.io
  • velesoftvelesoft
    edited July 2009
    Mister Beep wrote: »
    Hi, Vele.

    I wonder how exactly the "Mixing of two different colours is converted to static screen lines" looks like.
    I mean - could you add to the site one or two photos of GigaScreen pictures?
    (If you don't have any, I can send you several, for FatWare engine).

    I have only ZX48+ with composite video out. My ZX128+2 have bad pal encoder (TEA2000). I can't test effects with two videorams.
  • WinstonWinston
    edited July 2009
    cheveron wrote: »
    These converters aren't cheap though so I'll probably go with composite.

    Hmmm.

    I spent a bit of time being distracted by this: need a device to take RGB from a Speccy and make it suitable for a VGA monitor be expensive?

    I have to conclude, probably not. The converters that exist at the moment probably are pricey (if you can even *find* them) because they are designed for the general case - i.e. they require a good quality *fast* 3 channel ADC for the input (not particularly cheap), and a good quality *fast* 3 channel DAC for the output (not cheap either), and enough fast memory to support a 24bpp frame buffer of at least, oh, 768 x 525. Oh, and a well designed 4 or 6 layer PCB for good analogue performance.

    But an upscan converter specifically for 8 bit systems needn't be the panacea to RGB to VGA conversion, and the circuit can probably be simplified a lot. You can do away with having both the ADC and the DAC by supporting only 4 bits per pixel (because all you need to do is discriminate between being bright or non bright for analogue values, something that's easily done with a cheap transistor circuit). This of course means you need vastly less memory too (a 256K frame buffer would suffice), and the logic would probably all fit in a CPLD. If most monitors will support 100Hz at a PAL-ish resolution, you'd only need one pixel clock, divided by two for the PAL side. I'm probably missing something important given I've never tinkered with the video side :-)

    Hmmm. Tooo....many.......projects......
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