Or maybe instead of making an expansion card, just plugging something in the VGA connector that would read each pixel's color and apply it to the numeric/sharp picture. This will probably be more complicated and if your card has too dim/bright colors, this would also be applied to the numeric picture, however this would also free up one expansion slot which might be crucial for some of us.

This makes me think to something else too : it could be a neat feature to be able to mod the voodoo 1/2 to get a very sharp output. Some people would find this useless as the later voodoos have really sharp picture, but I think it could still be a good thing to have if you want to play the games that don't like anything but the voodoo 1 or 2

What a marvellous idea - you are absolutely right. Snoop the palette somehow and get pixel and sync data from feature connector.

If it does not exist, let's build one.

There's just a few issues that might need some more thought.

While you get pixel clock, H/V sync and blank signals from the connector, which do are everything you need to capture pure digital data, there might be slight differences between cards (hardware and software) in the video signal timing. There is no "data enable" signal that would say which pixels contain the image data, unless the blanking signal is used for that. However the blanking signal contains the border area as well, so if you could feed the pixel data through palette lookup to a DVI transmitter, you would have a non-standard custom video signal larger than 640x400 that also contains the borders, and the monitor would try to scale to full-screen. The signal might also be not centered. It could be possible to have some offset adjustments there to clip to 640x400 window based on the hs and vs pulses (that's called a DE generator).

The other issue is the refresh rate. Modern monitors and TVs do not necessarily accept 70Hz signal at all from their digital inputs, so your idea of converting that to 60Hz is valid. But in order to do that, you'd have to receive the 70Hz signal (or any custom resolution and refresh rate combination) into a frame buffer memory and send it out at 60Hz with standard clocks and timings accepted by monitors and TVs, maybe including scaling features to keep aspect ratio, borders or just fill the screen. That's only doable with special video processing circuits or FPGAs.

Deksor wrote:

This makes me think to something else too : it could be a neat feature to be able to mod the voodoo 1/2 to get a very sharp output. Some people would find this useless as the later voodoos have really sharp
picture, but I think it could still be a good thing to have if you want to play the games that don't like anything but the voodoo 1 or 2

Voodoo 1/2 cards don't have a feature connector. I think the SLI connector transmits analog signals.

Yep, Voodoo 2 SLI is analog. At least it's true for mainstream cards. Quantum3D cards could be digital though.