These overlays have varying amounts of scanline beam width variation/glow/overdrive effect.
The lowest numbered overlays have the sharpest scanlines and no glow/overdrive. The highest numbered overlays have the most glow/overdrive and the most beam width variation.
The “classic” scanline overlays are still here, they’ve just been renamed as options 1 and 2.
Instructions
For these overlays to work properly, you must:
1. choose an overlay with a resolution that matches the video resolution being used by RetroArch (e.g. use one of the 1920x1080 overlays if you’re using 1920x1080 for the video resolution).
3. set the aspect ratio to “custom.” (settings -> video -> aspect ratio -> “custom”)
4. set the custom viewport x/y to an appropriate size. Set “custom aspect ratio height” to 4x or 5x if using 1920x1080 as the video resolution; if using 1280x720 as the video resolution, set “custom aspect ratio height” to 3x (settings -> video -> custom aspect ratio height)