MiSTer FPGA Forum

HI
I just saw that the new core update supports custom aspect ratios. I use a sony pvm and when I use the old cores the screen stretched over the right and left edges.Can some one help me how to switch the neo geo core to a differenr resolution? I believe it needs to be 304x224 and the old cores I think were 320x224. Thank you

304x224=19:14 aspect ratio

In the updated MiSTer.ini spec:
Go to this section, uncomment (delete the ";") and change the first one to:
See if that works for you. If not then, put a ; there again to comment that line again (commenting means it will ignore that line), and then add this to the end of the .ini:
and see if that works. Otherwise, I'm not sure, someone else who has messed with this more may have to chime in.

What's special about this option? Won't messing aspect ratio result in shimmering when scrolling?

It might not result in shimmering on a CRT depending on the situation.

Doesn't hurt to test and see.

They asked about custom aspect ratios :shrug:

From what I understand, any time the resolution in either the x-axis or the y-axis is not an integer scale, you can get shimmering in the respective axis. The integer scale setting in mister is only guaranteed for the y-axis, and the x-axis is scaled according to the aspect ratio, which may or may not result in an integer scale. My understanding is that mister uses filters to reduce shimmering, by default, at least in some scenarios.

ash2fpga wrote: ↑Fri Jan 15, 2021 10:54 pm From what I understand, any time the resolution in either the x-axis or the y-axis is not an integer scale, you can get shimmering in the respective axis. The integer scale setting in mister is only guaranteed for the y-axis, and the x-axis is scaled according to the aspect ratio, which may or may not result in an integer scale. My understanding is that mister uses filters to reduce shimmering, by default, at least in some scenarios.

Exactly. You should be able to work around the lack of horizontal integer scaling by using this custom aspect ratio option. But that is much more of a hassle (especially with all the arcade cores), than if you could just enable integer scaling both horizontally and vertically (sacrificing correct aspect-ratio when enabling both).

I checked and I dont think custom aspect ratio works on analogue video output. I think the feature only works for hdmi.

There is a core option to toggle 304/320 px modes. This works on analog but it doesn't change where those extra pixels are i.e. what would be the overscan/border region in say a Genesis core, it just blacks out these columns on 320 px games. It seems that real Neo Geo systems worked this way and annoyed home users with this overscan stuff, probably less of an issue in arcade cabinets calibrated to deal with it?

Basically if you can't adjust your TV to deal then you have to enter the world of vga_scaler=1, which routs the HDMI scaler output over to analog. I would try a 320x240 resolution with vscale_mode=1 and vsync_adjust=2, and in the core menu options set aspect ratio to full and see how that goes.

Thank you for the tip but still not full screens. What I keep doing when I play the neo geo core its going to the service menu on my pvm and changing the horizontal size setting from 89 to down to 76

If you got a strictly 15khz PVM I think that's probably the best you can do. If it can go slightly above 15khz, you can push the vertical resolution slightly with vga_scaler, say starting with 260 tall. With an integer scale the neo-geo content should be centered with increasingly larger black bars on top/bottom that you hope show up in the non-viewable area.