Post count: 56

Genesis (and PSX, MasterSystem, limited NeoGeo and a view others) have a native resolution of 320×240. That’s a native 4:3 aspect ratio.
SNES, NES have 256×224, but on a CRT the X axis is stretched to fit a 4:3 aspect ratio.
So my custom_viewport aspect ratio settings also is 4:3.
And for each Y pixel of the game image, i have 4 Y pixels for the scanlines image. 224 x 4 = 896
I also use this settings for all emulators like Genesis and so on, technical it doesn’t fit the resolution of the scanline image because of the TV border, but it also looks really great.
If you don’t want a TV border, you can also enlarge the resolution to the whole screen of course but the Y Resolution should be a multiple of 3 or 4, so you can use 3 or 4 pixel for each scanline. Then you will have black borders on the Y axis, bit otherwise it looks horrible if you use the whole screen resolution, for example on a Full HD 1080 (/ 240=4,5) because every second scanline have 4 or 5 Pixels.