CRT-Yah! A new shader chain

[Jezze]

Not sure what else I could do to further reduce the blurriness of the NTSC effect. The recent changes should have eliminated the blurriness in the vertical (y) direction. But as for the horizontal (x) direction, I’d say that’s just the nature of the effect, esp. for the two-phase option.

Regarding the sub-pixel mask setting: 2-MG stands for magenta/green. So the sub-pixel mask consists of only two alternating colors instead of three as with RGB. This is actually nothing special; other shaders also offer this type of sub-pixel mask. Magenta/green usually appears more uniform, because the brightness between magenta and green is very similar, unlike the brightness between RGB.

However, a special feature of this shader compared to most others is the scaling of the sub-pixel mask based on the screen resolution. For example, at 1080p, the sub-pixel size is 1, while at 2160p (4K), the sub-pixel size is automatically scaled to 2.

Long story short, I don’t know why magenta/green works better for your LG OLED. The interaction of the actual sup-pixel grid of your display and the simulated sub-pixel mask can be quite complex and also can lead to artifacts, esp. with a sub-pixel size of 1.

[Cyber]

@Jezze

Long story short, I don’t know why magenta/green works better for your LG OLED. The interaction of the actual sup-pixel grid of your display and the simulated sub-pixel mask can be quite complex and also can lead to artifacts, esp. with a sub-pixel size of 1.

I was hoping this would be common knowledge by now but LG 4K OLED TVs before the G5 use RWBG subpixel layout, therefore the only CRT Shader Subpixel Mask that would align properly and evenly is RRBBGGX (and possibly XRRBBGG but I haven’t tested that on any OLED TV). Regular RGB or BGR Subpixel Masks would not look accurate at least close up to the screen because of this.

OLED subpixels. How do they work?

Here are some macro shots of Wii Sports running on an LG 55OLEDE6P using CyberLab Mega Bezel Death To Pixels Shader Preset Pack. The first ones are using CyberLab Wii, which uses Mask 6 at size 2, while the others use Mask 7 and 8 at different sizes. The last set uses Mask 6 size 2 with aperture grille layout followed by Mask 7 and 8 at various sizes. This could be the final verdict on the accuracy and capability of WOLED TVs to depict RGB phosphor triad emulation properly. So far it doesn’t…

[passballtotucker]

This shader looks really good. Is there a way to turn off the flickering though?

[Jezze]

You can turn off the scanlines jitter and also the jitter of the NTSC effect when activated:

• set “Scanlines > Offset” to 0
• set “NTSC > Jitter” to 0

There is also some animated noise you can disable:

• set “CRT > Noise” to 0

[Dante]

Hi, great shader for starters! Actually it’s now by default shader I really like it. I have a question though. For 480p content what settings should I set in order to have a more convincing look?

[passballtotucker]

Alt+Tabing and going back in gets rid of the flicker without adjusting any of those settings. Not sure what the issue is. Sorry, this is happening on other shaders too.

[Buccaneer]

FYI : With the newest version i had to turn down saturation from 1.15 to 0.95 otherwhise I got black fragments in bright Letters on different cores and systems across the board. As soon as I went under1.00 they were gone

[Jezze]

@Dante Depends on what you mean by convincing. Since you mention 480p, e.g. like Dreamcast or Naomi: This resolution is automatically down-scaled to 240p. You can return to 480p by setting the “Screen > Scale” to 1, or you try 360p by setting the value to 0.5.

@passballtotucker What video driver do you use? I usually go with Vulcan and rarely test the others.

@Buccaneer The shader code for saturation was actually not changed only the preset settings. Were you able to configure a saturation above 1.0 before? And what video driver do you use? I will test other than Vulcan, and try to reproduce this issue.

[Jezze]

I could not reproduce the issue with other video drivers. However, the saturation method I use could produce numeric errors, leading to NaN or Inf, which could be handled differently from hardware to hardware.

There might be a simple solution, which should prevent the potential numeric errors. Can you open the file crt\shaders\crt-yah\common\color-helper.h go to line 82 and replace:

    return saturation > 1.0
        // increase
        ? apply_scale(pow(color, vec3(saturation)), max_color(color))
        // decrease
        : mix(vec3(luminance), color, saturation);

by:

    return mix(vec3(luminance), color, saturation);

This does not give the exact same result as before, but is very close.

If that works for you, I will provide an updated version soon.

[Buccaneer]

Tested and I can confirm with that code it works flawlessly with saturation above 1.0. PS I use vulkan and the saturation was above 1.0 since a long time…sttrangely with the latest version the problem came up. Thx

[Cyber]

Hey great shader. I wish there was a way to control the NTSC Resolution or Resolution Scale because when I enabled NTSC things got way too blurry without any ability to fine tune it.

I tried loading my Blargg NTSC Video Filter presets but I got a black screen when attempting to load using Beetle PCE/SGX/CD. Apparently the NTSC Video Filter preset loading isn’t broken when using Beetle PCE Fast. This last part is for @hunterk, @Tatsuya79, and @barbudreadmon.

@Jezze On another note, besides the lack of WOLED specific subpixel mask layouts mentioned above, I sorely missed subpixel mask layouts for bgr displays, which is what I’m currently using for the most part but great work on a shader that makes it easy to keep things bright while remaining saturated and providing full opacity mask and scanline emulation and more!