270p Games – Mode to get proper integer downscaling on a 4:3 CRT

[cjd280]

Hi, I haven’t found a way to get this working well, and I think support likely needs to be added to the OSSC Pro at the firmware level to make it work.

Games like Shredders Revenge, Marvel Cosmic Invasion, Ritas Revenge, etc have their original artwork in 270p (480 x 270).  It scales up to 1080p at a perfect 4x integer, but the downscaling that gets done at 1080p is 5x and has lots of vertical shimmering.  Being able to downscale it 6x to a letterboxed 320 x 180 would solve this if my math is right.

I could be wrong and there is a way to do this already, but I’ve not been able to find anything here (there isn’t a search that I can find so its not easy) or reddit or youtube that covers this case.

[BuckoA51]

I think at 320 x 180 you’d just be throwing too much resolution away for it to look good.

[cjd280]

I currently set my PC to 480×360 and send that to the OSSC Pro and put it into scaling mode.  It looks almost perfect except you get some slight shimmer when things move vertically.  Most of the game ends up being side scrolling so its not terrible and the curve + non perfect geometry on my CRT masks it a bit.  Its much better than running the game at 1080p and using scaling mode in terms of the shimmer but its still not perfect.  Smaller text gets hard to read but otherwise the pixel artwork looks good.

I just took a video of my 480×360 in scaler mode on the OSSC Pro connected to my PVM, and then the game running at 4k with its built in CRT filter. I’m terrible at taking CRT videos so there is a bit of flashing on the screen but you can see the game art looks pretty good except when moving vertical.

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