Arbitrary digital video to HDMI upscaler

Discussion of development of software for any "obsolete" computer or video game system.
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lidnariq
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Arbitrary digital video to HDMI upscaler

Post by lidnariq » Wed Dec 30, 2020 10:16 pm

Apparently some people have written a crazy baremetal upscaler mostly on the Raspberry Pi Zero (plus a XC9572XL to handle nonuniform sampling as a fancy serial-to-parallel shift register):
https://github.com/hoglet67/RGBtoHDMI/wiki

Can't be used with the NES or SNES as-is, because the NES requires an extra stage for palette proxying, and both I think require fixing the missing pixel. Can't be used with the TG16 because it'll require palette proxying. But there are probably some other consoles that emit something easily used as input.

Currently achieved input bandwidth seems to be somewhere around 14MB/s, ish.
Last edited by lidnariq on Thu Dec 31, 2020 1:13 pm, edited 1 time in total.
Reason: better understand the cpld

Pokun
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Re: Arbitrary digital video to HDMI upscaler

Post by Pokun » Thu Dec 31, 2020 8:35 am

Interesting, although I don't fully understand it's potential as its analogue support seems limited.

lidnariq
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Re: Arbitrary digital video to HDMI upscaler

Post by lidnariq » Thu Dec 31, 2020 11:58 am

Mostly it's exciting because it's a very inexpensive solution that can be pixel-perfect, unlike a generic composite-to-HDMI upscaler.

But yes, it relying on a fixed palette at the input stage makes it hard to use with many video game consoles.

There's an input stage ( https://github.com/c0pperdragon/Amiga-Digital-Video ) that listens to the Amiga OCS's video chip and can produce video from that. I'm not sure how it solves the palette, though, and haven't found the relevant documentation yet Ah, OCS Denise literally emits digital R4G4B4 on some pins: https://www.amigawiki.org/doku.php?id=de:parts:denise - so it should be possible to consoleize a Game Gear as well

Oziphantom
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Re: Arbitrary digital video to HDMI upscaler

Post by Oziphantom » Thu Dec 31, 2020 9:19 pm

you could probably get away with a MegaDrive with an RGB cable as the bit depth is lower than the Amiga. Tg-16 also would be fine. SMS would be fine. SNES you will suffer quality drops badly.

lidnariq
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Re: Arbitrary digital video to HDMI upscaler

Post by lidnariq » Fri Jan 01, 2021 12:55 am

The reason that the OCS is suitable while the Genesis and TG16 aren't is how they're trying to do input stages on the cheap here. If you can find a fast enough triple ADC for a couple bucks you might be onto something, but right now they're building poor-man's flash converters and using the 4 bits as a 5-level ADC.

Unless you mean that there's some pin on the Genesis &// TG16 that emit R3G3B3 digital video, in which case I learned something new.

Oziphantom
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Re: Arbitrary digital video to HDMI upscaler

Post by Oziphantom » Fri Jan 01, 2021 1:14 am

ah the analogue is only 6bits, they are pulling data from Denise rather than getting A->D conversion or pulling the technical card as the Amiga does also output RGBI.

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