[quote=101987]With these settings, the overlay is being scaled with bilinear filter, which is blurring some of the scanlines and causing the moire effect you were describing. IMO this can be very distracting, particularly with vertically scrolling games.[/quote]
nope, it’s not being scaled. my overlays are 1080p, so if you set your retroarch video output to 1080p, no scaling takes place. i have scaled the scanlines ahead of time in gimp, but it seems to be a subtler effect, and not noticeable (to me) – see my screenshots.
the moire effect i’m describing is a feature of my TV (and others?) – i get it even when I’m using perfectly scaled 216 visible line games and 216 scanlines (5 x 216 = 1080 – I used a 1080p overlay of un-scaled 216 line scanlines, intiially), when the overlay opacity is too high. i think my panel doesn’t like concentric horizontal black lines and the brightness of them seems to waver (I have it set to ‘game mode’/post-processing off, of course).
i recommend folk fiddle with the setting to see what they like.
There are a couple incorrect assumptions you’re making, one of which is that most systems put out 224 horizontal lines of resolution, which is not the case.
…hence i’ve got the breakout section detailing the resolution of each system, as I check :) nes/snes, neogeo and megadrive are 224, which represents ‘most’ to me, but that’s my era I suppose.
[quote]If you’re losing important score/credit info, as you said you were at 5x scale, it’s likely because you are using 224 as the internal resolution instead of 240.[/quote]
nope, I was using 216 instead of 224, in the scenario I was talking about (this is the visible area you end up with when trying to 5x integer scale on a 224 line system). you can’t show 224 lines on a 1080p screen in a 5x integer scale (5*224=1120)
[quote]Also, regarding opacity, IMO you’re better off setting your display’s “backlight” setting higher to compensate for the loss of brightness. (This is not the same as the “brightness” setting). For example, with 4x scanlines at 100%, you would lose 50% light output, so you compensate for this by increasing the backlight by the same amount (eg., if your backlight is at 50%, you would turn it up to 100%).[/quote]My TV doesn’t have this setting :(
[quote]Also, regarding the dotmask shader, it will cause a drop in frame rate and input lag, but it is slight. I’m sensitive to these things, so it ruins it for me, personally.[/quote]Do you have a way of measuring this? None of the retroarch emulators seem to be able to display framerate for me.
[quote]With this said, could you please correct the misinformation contained in your post regarding the horizontal resolution of console systems? This kind of information can quickly and easily spread once posted, leading to more confusion and problems, and it works against the efforts of those who are working to preserve authenticity and accuracy. Thank you. 
The correct horizontal resolution is 240 for NES, SNES, Genesis, PS1, N64, PC Engine. This can be readily corroborated by using Google and searching “internal resolution (system name)”
However, there are individual core differences and bugs where the internal resolution isn’t right, Picodrive being a notable example. So the correct resolution for a system may not be the “correct” resolution for an emulator.[/quote]sure, I’ve added a note on what I mean by ‘resolution’ in this guide