MiSTer FPGA Forum

Lately I've been trying to find just the perfect filter for my tastes.

I came across the Composite blend filters, which in theory are just perfect, especially combined with scanlines. At first I thought I had found heaven. They looked perfect at first glance.

However after playing games with them for any length of time exceeding a few minutes, I realized that my eyes started to hurt, like it physically gives me a headache. I've come to realize that the type of blur these filters apply seem to trigger in me the a reaction that I can only describe as my eyes constantly squinting to try and focus on something that's out of focus.

I do not experience anything of the sort when using Bilinear or Gaussian interpolation filters, however there are none that are combined with scanlines that I can find in the default filters.

I was wondering if anyone else was experiencing the same reaction? Could anything be done to tweak the Composite blend filter to reduce/remove this out-of-focus effect (and yet keep the blur)? If not, is there a way to combine scanlines with Bilinear or Gaussian interpolation filters?

In case that might matter, I'm using 720p and integer scale on a 4K HDTV.

Thanks!

I get the nostalgia factor for filters in some cases. Especially in cases where you wouldn’t have seen completely square pixels due to 15KHz scan as opposed to 31KHz (difference between many RGB or lower CRTs and say VGA). In those cases though, why not use a scanline mode that mimics something higher end, yet still from the same time period. Like say 1084S, Diamond Scan, or other nice RGB monitor of the time period, rather than emulating a lower end TV or composite monitor?

I realize it’s down to personal taste, personal nostalgia, but if making your signal look bad for nostalgia is giving you a negative physical reaction, maybe try something that’s a notch better, but still time relevant?

Just a thought. I know we probably have different views on the merits of composite displays.

5x scaling/cutoff at 1080p will give more resolution for blurring shaders to work with and may yield better results, and there's also the soft scanlines filters for a less blurred scanline effect. But when it comes down to it, your eyes were probably better decades ago and could tolerate things they won't tolerate now. I found this out recently with a real consumer TV set, even though it was far larger and sharper than anything I had at the time, and the look is pretty awesome, its still tires my eyes/gives me headaches in a way that LCD panels (or even a VGA CRT) don't.

J3RK wrote: ↑Tue May 18, 2021 8:31 pm (...) Like say 1084S, Diamond Scan, or other nice RGB monitor of the time period, rather than emulating a lower end TV or composite monitor?

Where are such filters found? They don't seem to be part of the official filter list: https://github.com/MiSTer-devel/Filters_MiSTer

J3RK wrote: ↑Tue May 18, 2021 8:31 pm I get the nostalgia factor for filters in some cases. Especially in cases where you wouldn’t have seen completely square pixels due to 15KHz scan as opposed to 31KHz (difference between many RGB or lower CRTs and say VGA). In those cases though, why not use a scanline mode that mimics something higher end, yet still from the same time period. Like say 1084S, Diamond Scan, or other nice RGB monitor of the time period, rather than emulating a lower end TV or composite monitor?

I realize it’s down to personal taste, personal nostalgia, but if making your signal look bad for nostalgia is giving you a negative physical reaction, maybe try something that’s a notch better, but still time relevant?

Just a thought. I know we probably have different views on the merits of composite displays.

It's just a matter of convenience for me. I really just like the comfort of playing in my living room with my big TV, beefy surround sound system and everything. Of course playing on an actual CRT would be best, I know, but I don't have the physical space to build a proper comfy-couch style of setup to make this happen, hence why I'm going for the next best thing: replicating that look on my HDTV. Thanks for the advice though!

FoxbatStargazer wrote: ↑Wed May 19, 2021 1:10 pm 5x scaling/cutoff at 1080p will give more resolution for blurring shaders to work with and may yield better results, and there's also the soft scanlines filters for a less blurred scanline effect. But when it comes down to it, your eyes were probably better decades ago and could tolerate things they won't tolerate now. I found this out recently with a real consumer TV set, even though it was far larger and sharper than anything I had at the time, and the look is pretty awesome, its still tires my eyes/gives me headaches in a way that LCD panels (or even a VGA CRT) don't.

I don't want the 5x cutoff of 1080p. So yeah I've been using the Soft Scanlines for the moment. They're the next best thing but they don't quite give enough blur for my tastes, especially for pre-rendered type games like Donkey Kong Country. I'm looking for something that would combine bilinear interpolation with soft scanlines. I really like the SNES Classic's "CRT" filter that's basically just that, interpolation + scanlines. I tried opening the MiSTer filter files to see if I could somehow MacGuyver something like this on my own but I have absolutely no idea what I'm looking at or how to go about it... Ideally though it would be even nicer if someone could somehow tweak the composite blend filters to "fix" this out-of-focus effect that gives me eye strain, if that's at all possible. Real composite displays absolutely do not cause me this type of eye strain at all.

Oh! I wasn’t suggesting using an actual CRT, but rather scanline or filter settings that more resemble the higher end monitors of yesteryear.

The 1084 was Commodore’s 15KHz RGB monitor, and the Diamond Scan was a nice Mitsubishi RGB from the 16 bit era. Basically, the look would be softer scan lines, in order to remove the hard-edges blockiness that looks like early VGA DOS screen modes.

I’d go as simple as possible, so either horizontal or vertical scanlines depending on game.

MAME had a nice CRT filter that mimicked the aperture grill that was prominent in trinitron monitors and many arcade screens. It has a nice look that doesn’t smear the image. Not sure if there is one that would easily drop into the MiSTer though.

IMO, you should be able to find a good, properly scaled, soft scanline mode that looks like higher end vintage, that won’t hurt your brain

Might just take a bit more experimentation.

Ive been playing with settings like this since the mid 90s and it still takes me a long time to arrive at the perfect settings for a given system. I’m sure you’ll find exactly what works for you.

J3RK wrote: ↑Wed May 19, 2021 5:43 pm Oh! I wasn’t suggesting using an actual CRT, but rather scanline or filter settings that more resemble the higher end monitors of yesteryear.

The 1084 was Commodore’s 15KHz RGB monitor, and the Diamond Scan was a nice Mitsubishi RGB from the 16 bit era. Basically, the look would be softer scan lines, in order to remove the hard-edges blockiness that looks like early VGA DOS screen modes.

I’d go as simple as possible, so either horizontal or vertical scanlines depending on game.

MAME had a nice CRT filter that mimicked the aperture grill that was prominent in trinitron monitors and many arcade screens. It has a nice look that doesn’t smear the image. Not sure if there is one that would easily drop into the MiSTer though.

IMO, you should be able to find a good, properly scaled, soft scanline mode that looks like higher end vintage, that won’t hurt your brain

Might just take a bit more experimentation.

Ive been playing with settings like this since the mid 90s and it still takes me a long time to arrive at the perfect settings for a given system. I’m sure you’ll find exactly what works for you.

Oh! But where do you get these filters from? I've tried searching but to no avail...

I generally use the soft scanline modes right now as they give a decent look. They’re built-in usually in the second page of settings.

The aperture grill ones were in MAME, so I’m not sure if they can be used or not. It’s worth looking into though. Maybe I’ll try experimenting with that when I get a minute, and report back.

I've been using the composite blend filters in most of my cores for a while now, and haven't noticed any eye strain. My tv is a 50" plasma. Maybe temporal dithering is the problem? Having suffered eye strain in the past (and present) it's one of those things that is almost impossible to nail down the actual source of. In my case, I've had decent success in using a flicker-free monitor and taking regular eye breaks.

You could trying sending your 4K TV some non-integer resolutions if it accepts them. Like 1200p or 1440p, or maybe even 960p or 480p. And/or turn down the sharpness on your TV. Make it sharp on the mister side (vscale=1, maybe sharp scanlines) and let the TV blur things up a bit with its interpolation.

ioev wrote: ↑Wed May 19, 2021 7:55 pm I've been using the composite blend filters in most of my cores for a while now, and haven't noticed any eye strain. My tv is a 50" plasma.

Plasma presents the picture in a extremely different way then a LCD does and "can" very well be the only reason you do not get strained eyes.
Or you are simple more tolerant then the glowing shroom is.