Scaling Woes - Analogue IO VGA > Corio C2-2355A > PVM 1954Q

[achtongue]

Hello folks.

I'm having some weird issues when using a Corio 2 with my MiSTer.

My chain is Analogue IO VGA > Corio C2-2355A > PVM 1954Q.

Following this guide (https://shmups.system11.org/viewtopic.php?t=63226), i set up the Corio 2 to downscale to 240p.

My primary use for the MiSTer + Corio 2 is to center and zoom on certain cores that don't seem to display right (Amiga for example).

Running the MiSTer with no defined "video_mode" and "vga_scaler=0", I get a strange shimmering effect in a couple of areas on the screen. I am including a video (https://imgur.com/lxaZpjA) of 240p test suite via snes core to show what I'm talking about.

It looks like someone else had a similar issue on the shmups board and the suggested fix was to feed the corio a 31khz signal (i.e. 480p) so that it could properly downscale.

When I do that, i get a weird sizing issue that i'm hoping someone can help me with.

I change mister ini settings to "video_mode=6" and "vga_scaler=1" and this is what happens:

https://imgur.com/PsYwPpk
https://imgur.com/QBDmPST

Any ideas?

Thanks in advance for looking!

[FoxbatStargazer]

I would bet with the "input 480p" they had in mind using the scandoubler rather than the scaler. vga_scaler=0, forced_scandoubler=1. That's 31khz output in most cores.

Still the Mister itself is capable of scaling 240p/15khz resolutions. For example, vga_scaler=1, video_mode=640,244,60,cvt. Use aspect ratio = full/wide in the core, and turn on integer scaling.

You can get further control by using the longer form of video_mode to specify the blanking settings, that will help you size and scale the output. You can also try to match the horizontal resolution to a multiple of the original system, or else just use something like 1920 wide which will get you close enough with horizontal interpolation.