New CRT shader from Guest + CRT Guest Advanced updates

[Cyber]

Finally! Thanks @guest.r

I must say however that things seem very temperamental, with very slim margins among balancing artifacts, noticeable, undesirable flickering/noise in dither patterns and getting the now infamous “m” to look legible.

Disabling artifacting and fringing turns it into that smeared mess it was like before at Resolution Scale settings which fully blended dithering!

Increasing artifacting increases flickering, increasing fringing is even worse.

Deblur and Preserve edge colours played a significant role in taming some of the wilder artifacts.

Wish temporal effects could be more transparent though. Are things being affected by frame pacing issues/limitations in RetroArch?

[ynnad4]

maybe this article can be useful for some of you:

Developers Speak on Designing Game Artwork for CRTs | CRT Database

[guest.r]

New Release Version (2025-11-11-r1):

Notable changes:

• ntsc: small cleaup, some small tweaks
• pal: some small tweaks
• original image reveal shows stock pass instead, to show grading changes also
• gamma correct added to “grading” parameters
• mitigate masks on mid-colors options retired
• afterglow can be now Original History or Source based
• afterglow display threshold is now a parameter
• important : ntsc and pal preset interlacing changes: interlacing is now active before ntsc/pal shaders
• ntsc retains compatibility with prior presets, pal with simple presets only
• corner and border effect now support integer under-scale (through shader)
• New: Raster Bloom has new parameter section.
• New: Raster Bloom effect smoothing deviation with bright ‘screens’ option added.
• New: Preserve Fonts option added to ntsc shaders. Viable for setups, which dissolve dithering, works better with checkerboard situations, works only with +adaptive sharpness.
• Edit: small update

Download link:

https://mega.nz/file/4xplxJbC#-MG9YcKMw3Hmx5rSLs_IT16zeaPCMSdmroyEAEV9ULY

Feature Example:

Original:

With Font Preservation:

Disclaimer:

Checkerboard and bar de-dithers usually apply very complex logic to dissolve dithering patterns, current implementation is quite simple, and works better with checkerboards. Still in “beta”.

[ANK]

Just gave it a quick test, seems to work pretty well!

Just to clarify, the more negative I set the “Raster Bloom Smoothing Bright Deviation” the more sensitive it is to bright screens and vice-versa?

[guest.r]

Yes, negative deviation values make the effect more jumpy with brighter screens.

[Jobima]

@guest.r

New Release Version (2025-11-11-r1):

that a very good update! thanks!

the font are indeed will be better with the new option

also I like the new Raster Bloom update

but I will not post a preset update yet, since it has crt-black_crush-koko which is not added to the slang repo yet

[Cyber]

@guest.r

New : Preserve Fonts option added to ntsc shaders. Viable for setups, which dissolve dithering, works better with checkerboard situations, works only with +adaptive sharpness.

@Jobima

that a very good update! thanks!

the font are indeed will be better with the new option

I second this, It works!

@guest.r

• afterglow can be now Original History or Source based
• afterglow display threshold is now a parameter
• important : ntsc and pal preset interlacing changes: interlacing is now active before ntsc/pal shaders

Would this resolve the issue @Jobima was having with interlaced content that wasn’t happening with the Phosphor Persistence shader?

[Nesguy]

@guest.r WOW, nailed it with this update. I was just thinking about this font problem the other day, I could never really get font edges to look completely right no matter how much I fiddled with the sharpness settings. This solves the problem!

[Jobima]

@Cyber

Phosphor Persistence shader

I use Phosphor Persistence shader since it can be used after interlaced to do some Phosphor Persistence magic that help in reduce interlaced flickering, unless you mean this

[Cyber]

I was just inquiring as to whether you could now use CRT-Guest-Advanced to do what you previously needed to use Phosphor Persistence for since these changes were implemented by @guest.r.

@Cyber

@guest.r

• afterglow can be now Original History or Source based

• afterglow display threshold is now a parameter
• important : ntsc and pal preset interlacing changes: interlacing is now active before ntsc/pal shaders

Would this resolve the issue @Jobima was having with interlaced content that wasn’t happening with the Phosphor Persistence shader?

[petran791]

I tried the ntsc shader and I noticed an issue where the grass on a soccer stage on TT Acme Allstar on Genesis would be garbled during motion, as if Rainbow filter was enabled. HD shader version displays it fine in motion

Because shader has so many options, which is the one to disable that effect?

New sonkun crt guest advanced hd presets thread

I notice in a specific Mega Drive game (Tiny Toons Acme All-stars, ntsc) that when I pick soccer and play in Forest stage and pick Rainbow or Artifacts shaders, the shadows on the field become garbled during movement. Though that was not the case on the late December version of the shaders.

[guest.r]

@petran791

Because shader has so many options, which is the one to disable that effect?

There are basically two options, one is to merge fields, other is to reduce fringing or maybe artifacting.

[Jobima]

hi @guest.r

I wonder if it possible to have mixed interlace mode that will do mode 3 in moving areas and mode 4 in static parts of the frame, to kinda do adaptive deinterlacing

[guest.r]

Thanks for the suggestion. You can also shed some light on the effect purpose, like when and where this should work better compared with regular interlacing.

It can also go an other way, like static interlacing with edges and dynamic for surfaces. This, for example, would reduce flickering etc…

[Jobima]

@guest.r

It can also go an other way, like static interlacing with edges and dynamic for surfaces. This, for example, would reduce flickering etc…

in fact that what I want, mode 4 but if there are moving it will use mode 3 so it will not has comb, perhaps with few fading pixels that average both modes between the two areas to have homogeneous mix

edit: maybe its better to make the mix adaptive, which mean if the different in pixel between the previous frame and current frame was big it will overlay from mode 3, if it small it will merge (average) mode 4 with mode 3

[Jobima]

@guest.r

New: Ntsc rainbowing feature vertical fidelity improvements.

I find another case that still has the problem or https://files.catbox.moe/qzu24k.mp4

[guest.r]

It is how it is, @Jobima, i think it’s gonna stay with current implementation.

[guest.r]

New Release Version (2025-11-16-r1):

Notable changes:

• Preserve Fonts options is out of Beta (NTSC), should work better, works very nice with preserving Checkerboard dithering, use lower values with Bar dithering situations.
• New NTSC filtering option added, which doesn’t affect Chroma mod. frequency. Can be useful.

Download link:

https://mega.nz/file/lsYVgYKA#qhBViGxer3SPzIfYlU6MvNw5orJgOykA95uFG_w-yWU

[Jobima]

I ended up using ntsc_rainbow1 = “3.000000” which dont flickered like 1 and 2

[guest.r]

A good choice for some resolutions indeed. I deliberately added more options, since 1&2 are heuristics based.

I would also like to explain a bit, how the new Font Preserving functionality is to be tweaked. Some logic is contrast based and most games work nicely with parameter setting like 0.30. It’s “safe” to play Sonic Waterfalls like with below 0.36, since both waterfall and fonts are both “non-checkerboards”.

Checkerboard patterns are quite safe not to be re-dithered…

Overall, I’m quite happy with the results, still I didn’t make it a default setting, since it’s a bit resource consuming with higher resolutions. Also NTSC Adaptive Sharpness is needed to be active.

Normal:

Font Preservation: