Finally got my hands on a nice 4K MiniLED monitor to use with Megatron. What is the recommended way to increase brightness in the Megatron shader without introducing a tremendous amount of clipping? I’ve confirmed that HDR is working as it should, but the image is still lacking brightness- I’ve set my paper white and max luminance settings according the to the usual recommendations (max luminance for the display is 1000 nits, and I’ve set paper white to 600). If I increase brightness in the shader to around +25% the brightness is great, but hard clips a lot of the high end.
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I’ve noticed that increasing TVL helps.
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In general if the Peak and Paper White Luminance are too high, (regardless of what the specs or reviews say) you can get a lot of clipping.
For my use case, I found that setting the Peak and Paper White Luminance to the same value worked best on my TV in HDR Game Mode.
You can use a white screen or a screen with some white text to fine tune the Peak and Paper White Luminance Values to a point where it’s not clipped anymore.
So don’t push it to the theoretical max. Leaving a little headroom might actually look better.
I don’t use brightness to increase the brightness, I use Gamma In. I also use Saturation a lot. You can lower the Saturation as well if things are clipping.
I would add that @Azurfel has been working on an overhaul to the way the shader handles HDR Tonemapping among other things, plus you can set Megatron to SDR/SRGB Mode and have another system for example Windows 11 Auto HDR handle the Tonemapping.
You can download @Azurfel’s test version from his GitHub.
By the way, if you find the default Megatron presets too harsh or too raw, you can use some of my presets as a starting point. Many of them have a more up to date version of the CRT-Guest-Advanced-NTSC component included plus some also have Super-XBR integrated.
So you can then do some further adjustments via the NTSC-Resolution Scale and Chroma/Blending controls and more!
Update:
I can’t believe I didn’t mention this as this is probably as equally important as everything I mentioned before concerning overall brightness but you have to be very careful with the scanline dynamics as this can easily make or break your preset when it comes to brightness.
Especially if you’re just getting used for the shader, you might want to stick with or keep those settings close to defaults as you find other ways and settings to improve and fine tune brightness. Once you get the hang of those then feel free to indulge in some further scanline experimentation.
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Hi @nesguy hope youre well - ironically for brightness dont use the brightness setting - thats kind of a faux brightness thing. On my qd-oled I have to have 1000 max nits and around 200 paper white nits. You should use the default preset in the hdr folder and then adjust paper white. Failing that maybe the tvs power limiters are kicking in or something? I have to have my tv in game mode if that helps.
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When you use aperture grille with all the same settings do you get the same problem? Basically aperture grille and slit mask should be identical except for the mask has horizontal lines in it.
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I can’t say that I do or ever did. It’s one of the reasons why I’ve avoided the other mask types until now. I’ll double check it though just to see if it’s something that might have been there but just overlooked but with the way I do things I think I might have noticed it.
Can this be somehow related to precision/rounding error or a small bug/typo in the math that calculates the scanlines?
Also, my apologies for the screenshots above, I took more than those so I can share additional ones if necessary but imgbb was throwing a fit probably due to the number of pics I was attempting to upload at a time and I was very tired when trying to upload, document and convey the issue.
Update:
I loaded up the same preset I made those pictures with and switched from the Slot Mask to the Shadow Mask then to the Aperture Grille and the issue does not exist when using the Aperture Grille. Scanlines look symmetrical/uniform/consistent/great!
Update:
I took some new photos in order to better illiterate the issues I’ve been having with uneven/inconsistent scanlines/scanline gaps in all the other Mask Types besides Aperture Grille.
The image hosting issues should also have been resolved.
Slot Mask
Shadow Mask
Aperture Grille
Slot Mask - Deconvergence Off
Slot Mask - Deconvergence Off, Zoomed In
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That’s been working best in my case, as well. It was the brightness setting causing the clipping.
Would this be the “CRT” gamma? I always get confused on which one is input and which is output.
I’ll check this out! I do feel that there’s a bit of “digital vibrancy” or something that’s missing from the image, even after setting everything up correctly.
I suspected as much, thanks for confirming! And doing well, thanks. Hope you’re also doing well, and thanks for your continued support on the shader!
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Excellent, I’m glad you sorted that out.
Yes, most times I’m not in front of the menu when posting so the terms might not be perfectly accurate plus I think I read @MajorPainTheCactus refer to it as “Gamma In” once.
Hmmm…have you tried prepending the decoupled CRT-Guest-Advanced-NTSC or even using my pre-integrated version from my preset pack?
I have presets which use 3 variations, Stock Megatron, Stock Megatron with CRT-Guest-Advanced-NTSC integrated and Stock Megatron + CRT-Guest-Advanced-NTSC + Super-XBR integrated.
You can do a lot to the image using a combination of the NTSC effects as well as the Chroma/Blending and various Sharpness settings.
I only used the Original decoupled CRT-Guest-Advanced-NTSC which doesn’t include the Horizontal Filtering Section but both should be available if you look back in the thread.
I also did some tweaking to the Shader/Scaling settings in order to have the NTSC Component work even better.
Perhaps after you try these out, you can balance higher Saturation Levels with Gamma. You might see nice results if you start high with the Gamma (Darker, then gradually work your way towards brighter settings).
Don’t be afraid to push the Saturation. You can use the 240p Test Suite to confirm if it’s causing clipping.
If you change TVL you have to readjust everything by the way.
Feel free to take my presets for a spin.
I’m really looking forward to seeing things continue to improve with this shader, especially what I would consider the fundamentals but we would need more people like yourself to stick with it and identify the little outstanding bugs here and there and point out where might need some improvement.
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Slot Mask - Deconvergence Off, Zoomed In, Cropped
@MajorPainTheCactus, @Azurfel, @Nesguy I’ve been analyzing the above image and what appears to be causing the uneven scanlines issue in this case is the differring interaction between the Odd and Even Scanlines with the horizontal slots of the Slot Mask.
When the Scanlines align perfectly with the Slots, the scanlines appear dark and sharp.
When the Scanlines align with the middle of the Phosphor triad and the Slots are close but above or below the Scanlines, the scanline appears less intense and less sharp.
What might be needed is some sort of mitigation baked into the Shader to ensure that the conditions which produce the undesirable artifacts do not occur.
So probably a vertical Offset to the position of the entire phosphor grid (or all of the horizontal slots themselves.
Or an adjustment to the height of the phosphors at the various TVLs to values which might minimize the chance of this.
In the meantime, I can try to play around with the existing options to see if I can find a different TVL/Display’s Resolution combination or maybe build upon a preset which uses a slightly different phosphor height.
This phenomenon is also pretty glaring when the Mask Type is set to Shadow Mask at 300TVL.
I would really like if we could customize the Shadow Mask by being able to rotate/stagger the dot pattern to allow us to fine tune the look and better match our individual displays’ varying subpixel layouts.
Am I correct in my thinking that the CRT-Guest-Advance family of Shaders already has some sort of consideration for these types of scenarios @guest.r?
I could remember observing the SlotMask and scanline interaction a while back and wondered how the Horizontal Slots never seemed to be symmetrically aligned or evenly spaced in relation to the Scanlines.
I felt it was a bit strange but now I can understand the benefit.
@MajorPainTheCactus I’m thinking that if I lower the scanline intensity, to make them very light or almost invisible that I might not see this particular undesirable interaction. I’m now getting familiar with the controls so I’ll have to play around with them so see how I can go about accomplishing this.
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Part of the problem might be the regularity of the pattern? On a CRT, the scanlines don’t always fall on the same spot on the phosphor. How does it look when you disable integer scaling? Edit: nevermind, it doesn’t really help
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The first thing I tried was setting the Scanlines Max and Min to 2.00, which effectively disables the scanline Gaps and it the “problem” obviously went away.
2.00 is too high of a value for the min/max though, so I lowered it to 1.00 and it looks beautiful.
Reminds me of my old CyberLab Slot Mask CRT 1P2RTA preset.
On checking with a white screen, the problem is still there though.
I’ll probably try gradually decreasing the Scanlines Max and Min to see where the “breaking point” is where the artifacts reappear then try playing around with the Scanlines Min to create some dynamics.
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Isn’t this just a classic moire pattern? I think the only thing that’s going to work is to reduce the strength of the scanline pattern and/or the mask pattern, so you’re probably on the right track.
On a CRT it isn’t a problem because the beam hits on a slightly different part of the triad each time.
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Yep, I guess so but it took some close analysis of clear zoomed in photos to finally acknowledge and identify it as such.
There might have also been confusion caused by the other pulse like artifacts seen on 480i content.
On another note, I set the Scanlines Min/Max to 1.30 and things look much more consistent! Just have to adjust the Min slightly to create some dynamics.
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I can still see it in motion, though 
I wish I had never read these posts, lol.
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Well we can all work together to understand the Shader and it’s characteristics even better and report and assist in fixing bugs along the way so that eventually you might not have to see anymore undesirable things.
In the meantime, here’s how things are looking now!
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I think the solution will be more resolution. Looks fine at 12x, but we need 5k for that
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For whatever reason, setting the display resolution to 8k seems to help with the slot mask moire, although it doesn’t completely eliminate it (using a 4k display).
A scale of 12x will completely eliminate the problem.
Can you please give these a try and let me know what you find, when you have a moment?
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This is how you switch TVLs and Masks in Sony Megatron.
This plus trying out the different Presets which might default to different Mask characteristics.
So what it did is make the Slot Mask pattern shorter, which can be desirable in some cases.
Looks good, that’s why we really need people like yourself to see this shader achieve its full potential.
On another note, have you tried using HDR with other shaders now that you have an HDR display?
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I’m not sure how to get other shaders working with HDR? I’ve enabled auto-HDR in Windows.
I did try Azurfel’s edits to Megatron and it provided a noticeable improvement, I think.
In guest, mask 12 + slot mask width 3 is working pretty well (this might be the same mask configuration as Megatron slot mask 300 TVL 8k?) I currently can’t take screenshots with Vulkan so it makes it a bit difficult to see what’s going on.
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You can temporarily switch to the D3D11/12 driver, make sure HDR is on in Windows and Enable Experimental Features is toggled in GeForce Experience.
You should then be able to take HDR+SDR screenshots in jxr format by pressing Alt+F1.
You should be able to capture video by pressing Alt+F9. Alt+Z brings up the Shadow Play Menu where you can do things like enable custom bitrates.
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