Sony Megatron Colour Video Monitor

With HDR you definitely need to adjust settings to your monitor - until we have a HDR calibration wizard then sadly this just has to be played about with - set peak luminance to your monitors peak luminance, paper white luminance a little above half way and contrast in the 3-4 range but it could be totally different.

Also set your scaling to integer and see if the weird line goes away - let me know if it does or doesn’t.

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Wow this is great - I presume the left hand side is in cd/m2 and the bottom is just percentage of screen or something? Is this basically a histogram of the pixels?

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It’s lux and white brightness on bottom

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Could also be a rounding issue. It might help to multiple the texcoord assignment in the vertex by 1.00001 or whatever.


I get this too. With DX11 I get some cyan colored vertical lines and even some image crawling. Maybe one of the passes needs some filtering.

I’ll get onto this shader glitch now that I’ve added HDR support to our Vulkan driver!


Hi @Arviel hopefully this is fixed now (dependent on the github pull request being merged). Thanks to @hunterk as the rounding was exactly the problem and saved me a lot of head scratching.

In PAR aspect ratio:


Hey awesome work adding HDR to Vulkan.

Are there HDR options for luminance and all that like on DX11/12?

I couldn’t find them in the ui.


Hi sorry it hasn’t been merged yet so you’ll have to wait but yes when that pull request is merged it should be identical.

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Altered the sharpness of the shader to be better match my PVM 2730 so should be a slightly better picture.


Sorry for the confusion! By “pixel grid” I’m referring to the LCD pixel grid.

At 1080p it’s very difficult to take a completely convincing photo because if you zoom in enough to see the emulated RGB phosphors, the LCD pixel grid becomes visible (sometimes called screen door effect). You can somewhat hide this by blurring the camera slightly but it’s very difficult to completely hide the LCD pixel grid while keeping the RGB phosphors distinct.

I’m wondering if 4K resolution is enough to solve this issue, plus I just wanna see some shots of the shader working at that distance. :slightly_smiling_face:

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In response to an earlier comment: some time ago there was an image in this forum somewhere demonstrating that a small BVM = medium PVM = large Wega, in terms of scanline shape and darkness.

In other words a 9” BVM has the same scanlines as a 32” Wega, etc.

so, yes, screen size is a definitely a factor :slightly_smiling_face:

“PVM” has just kinda become shorthand for “well-defined scanlines”

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I just downloaded today’s nightly (2022-01-07 10AM) and couldn’t get Vulkan HDR to work. Thoughts? Thanks for working on this, btw! :+1:

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The PR has not been merged yet:


I followed these suggestions and WOW! what a difference. I can now see the appeal of using an HDR-based shader. Everything has this underglow to it, like you would see on a CRT. Also the weird line is gone, thank you for the fix!


@Arviel Thanks for the photos it’s greatly appreciated!

Your display is a LG CX right? I’d love to see that in person - I’m currently trying to make up my mind what TV to get a LG C2, Sony A95 (QD OLED) or Samsung QN900B (8K) or QN95.

Im thinking an OLED maybe too good though as on a CRT you do see a fairly large natural bloom around bright areas like you see on QLEDs (incorrectly). QNEDs also go brighter to support higher end PVMs (as in narrower scanlines)

Also the slow response time of an LCD I’m thinking is more like the phosphors of a CRT as in they aren’t instantly on or off like an OLED is.

What are your thoughts? I know OLEDs are the superior technology for gaming etc but possibly not for retro gaming purposes? I don’t know - I’d love to hear from someone with experience of them.

I also today slightly updated the shader if you get want to get latest.


I’d say the LG CX is the best purchased I’ve ever made as far as gaming goes (besides a PC). The picture quality of OLEDs truly is something else, specially in HDR which can be ridiculously bright as I alluded to before. OLEDs also have basically no ghosting due to the fantastic response times. Typical LCD monitor don’t come close. Shaders of course look great, the scanlines are truly black.

The biggest con to OLEDs is the size. Mine is 48 inches and I had to buy a separate mount stand so I could sit far back enough to be comfortable.

The C2 might be perfect for you as it comes in a smaller size of 42 inches. If I didn’t already own a CX I would have bought the smaller C2.

Here is a recording of Mega Bezel shader on my CX. If you have any other questions feel free to ask.


If you look up enough vids online, there’s no denying that OLED is king – especially now with HDR. I’m doing HDR + Black frame insertion and have reasonably bright picture quality.

IMG-20220107-151738 IMG-20220107-151815

this is with crt-royale-kurozumi.slangp and HDR + Black Frame insertion. About as bright as SDR without BFI!

(@MajorPainTheCactus I hope you don’t mind me posting this here; it feels like this is the HDR thread now :smiley:)


@c9f5fdda06 No absolutely not - love that your posting stuff here!

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Hi @nesguy firstly loved reading your investigations someone above posted.

Yes so I definitely don’t think you can see the LCD pixel grid but that’s mainly because I’m using a 27inch 4K display. When you are sitting at the right distance from it you also can’t see the RGB pattern either - just like you would with an actual CRT - it behaves just like a CRT in other words.

I tried taking a picture from that distance but I’m not sure it really shows what you are looking for as it’s lost a lot of detail due to clipping. I’ll post it here when I get a chance.

Legend of Zelda at about 3-4 feet away I’d argue looks better than my actual CRTs due to the colour repro and high brightness BUT keeping that softer CRT look.