Sony Megatron Colour Video Monitor

[Cyber]

@MajorPainTheCactus

TV if it occured so I’m not sure why you’d want it in a CRT shader.

I get this you know but the fact is the shader looks pretty different depending on what TV or display is being used. I’m on a 4:2:0 TV so maybe a hue setting can help dial things back if they are off. I know that same can be accomplished probably by using the parameters you have provided there already, it’s just that I’m already used to Dogway’s controls. Hue is important because depending on the mask strength, individual LCD subpixel layout or mask size, colour can be thrown off a bit at least with the GDV which is what I’m used to.

Don’t feel any pressure though, I’ll try to learn how to do things using what’s available in this great shader.

The phosphor emulation is top notch, has me wondering if I can coax GDV phosphors to look similarly on my TV!

[MajorPainTheCactus]

Yes ok so I’m trying to understand how are you expecting a hue control to help with chroma compression as in your 4:2:0? 4:2:0 will be lowering the resolution of the chroma channels (or images if you will) it won’t be fixed by rotating through the hue axis. The HSL and HSV colour models are very different systems to YIQ or RGB.

[Cyber]

Don’t worry about it. I was talking based on my experience with playing around with mask strength and size settings on different types of screens.

Now that I’m getting more familiar with the Shader, I’m seeing better results. I had something looking pretty good earlier but I accidentally saved my new settings with the same name as my reference and it messed everything up. Perhaps some sort of check and fallback to Full Presets might avoid this taking place.

It’s okay though, I’m going over your included presets again and I kinda know what to expect from my TV now so I should be able to get things back the way I want them to be.

I really had it set nicely though. Can’t even remember which of your presets I started with.

[Nesguy]

Yeah I’ve honesty never found the hue controls to be particularly useful. I personally have never used it and I’m not sure what situation you would use it for.

[hunterk]

Throwing the hue off is something that can happen with mismatching mask vs subpixel layout, but you wouldn’t want to try and compensate for it with hue controls because it would just clip/crush everything.

[MajorPainTheCactus]

Thought I’d being this problem solving over here:

Please show off what crt shaders can do!

@Nesguy and @MajorPainTheCactus don’t pay too much mind to those screenshots as I can’t even remember which preset is that. I lost a preset I had where I had just found that things looked somewhat nice so I basically have to start over. I don’t even remember which of @MajorPainTheCactus’s presets it was based on. On my TV there’s a lot of variance in the output (including colour and brightness) depending on which TVL is selected and also which Type of mask. Shadow Mask seems to work the best a…

I think the green maybe to do with your chroma compression i.e 4:2:0 is there anyway to use 4:4:4 even if it’s as a test? I see the Megatron being green when I play it over Parsec with 4:2:2 chroma compression.

[Cyber]

@MajorPainTheCactus

is there anyway to use 4:4:4 even if it’s as a test

I can get RGB: 4:4:4 if I set my desktop to 1080p. I might be able to get it at 4K if I lower my refresh rate to 30Hz. It’s probably not a panel limitation but more to do with the HDMI version and TV’s chipset.

[MajorPainTheCactus]

Yeah absolutely it’ll be a bandwidth issue with your hdmi cable or port but as I say just for test purposes put it to 4:4:4 and see if it resolves some/all of the issues. Just trying to figure out what are shader issues and what are setup limitations.

[Cyber]

No problem, time is always a limitation with me so I’ll give it a try as soon as I get a chance.

@MajorPainTheCactus

Yeah absolutely it’ll be a bandwidth issue with your hdmi cable or port but as I say just for test purposes put it to 4:4:4 and see if it resolves some/all of the issues. Just trying to figure out what are shader issues and what are setup limitations.

So I was able to set my computer to 4K 30Hz RGB 8-bit Full and the difference was night and day. I reset every setting to default using the Megatron Sony PVM preset and it looks great. Just had to set it to SDR and BGR and boost the brightness on my TV a little.

I was able to use all 4 TVLs. The phosphors appeared to be in RGB order for 600 and 800TVL while at 300TVL the order appeared to be BGR. I couldn’t tell with 1000TVL because it was too fine and I haven’t looked at my photos yet.

When I put my desktop back to 4:2:0 everything is back to being a mess. The easiest way to compensate was to set the colour on the TV to the max, 100.

At these settings, I see uneven scanlines and some slight moire artifacts depending on my viewing distance from the screen and what color is being displayed.

So 4:2:0 is basically a no go, I would say. It can be done but so far not without compromising the quality of the shader at least based on my efforts.

RGB 8-bit Full on the other hand, just works!

600 TVL (I think)

300 TVL

300 TVL

300 TVL

300 TVL

[Nesguy]

Yep, that looks great now. Defocusing the camera a bit until the LCD grid disappears would help the phosphors look more realistic but the human eye does that anyway IRL.

Did you do anything to the scanline settings or are those the default settings? I think there’s almost too much beam variation (never thought I’d hear myself say that).

[Cyber]

@Nesguy

Did you do anything to the scanline settings or are those the default settings? I think there’s almost too much beam variation (never thought I’d hear myself say that).

I don’t think these are the default setting for this particular preset, which is the MegaTron Sony PVM preset. I went through and manually set all of the settings including scanline settings to default. The only things I changed were HDR to SDR, RGB to BGR and I tried the different TVL settings.

On my TV, all I did was bump my brightness from 35 to 50, I also experimented with 65 but 50 might be good enough for me. My backlight was already at 100 in so I didn’t have to adjust that.

@Nesguy

Defocusing the camera a bit until the LCD grid disappears would help the phosphors look more realistic but the human eye does that anyway IRL.

I could’ve tried that but I went with the standard settings of ISO 100, WB 6500K, with AF. I took some shots initially at 1/60 Shutter Speed but then I switched to 1/30 because I had to run my TV at 30Hz in order to get RGB 8-bit Full colour.

Getting those shots was weird because while viewing the phone screen the image kept changing the colours and brightness were going all over the place and there were lots of lines and other noisy artifacts that were not a part of the final picture. Perhaps manual focus might help in this regard as well.

So what I’ve gathered from this is that this shader doesn’t work as intended in YCbCr4:2:0 mode.

[MajorPainTheCactus]

Amazing @Cyber so glad we were able to iron out the kinks!

[GPDP1]

So I thought I’d share a mock-up of what my particular setup (Sony Megatron with custom YMC 800TVL mask at 1080p upscaled to 4K) more or less looks like:

Basically, I took a regular screenshot of this shader at 5x scale at 1080p, then enlarged it to 4K resolution using the “preserve details” algorithm in Photoshop. I don’t know what algorithm LG uses on their TVs, but this looks remarkably close, only difference is here I’m using CMY whereas on my TV I use YMC, so the phosphors are reversed. Image is nice and bright, and while the image and the phosphors are slightly softened, at a distance it all blends together nicely.

I would advise people in a similar situation as I am (have a 4K TV but a potato GPU incapable of driving it) to try this out.

[Cyber]

@GPDP1

but a potato GPU incapable of driving it) to try this out.

Are you sure about this? This shader is pretty light.

[GPDP1]

At 4K, I meant. Of course, I’m still not exactly sure given I am not even using appropriate cables. The statement stands, regardless.

[MajorPainTheCactus]

So just to say the default settings for Megatron aren’t really intended to be used in practice. They’re instead meant to show what is the ‘neutral’ or middle point for each setting.

Just to also point out that although this shader will emphasize the problems with 4:2:0 chroma subsampling anything with frequency detail - text, games, video etc is going be affected by this as your chroma images are quarter resolution i.e 540p instead of 1080p say or 1080p instead of 4K.

[MajorPainTheCactus]

I’d really try to see if your GPU will integer upscale for from 1080p to 4K. Pretty much all drivers do this now. Better still I’d try to get your TV to do that - it’s an LG right? An OLED? They should allow you to do that I think - certainly the C1 does.

Then I’d use a RGBX mask to give you a 300TVL CRT image but of course for brightness you may want to stick with the CMY one - I think also @Nesguy proposal of simply RGB isn’t too bad either for roughly 450TVL. But of course thats all personal preference.

[GPDP1]

Again, the issue is with my current setup, I can only achieve 4K at 30Hz, which is unacceptable. So indeed, I have my TV do the upscaling, though it is not an OLED, but rather a VA panel.

BTW I just figured out how to control the horizontal sharpness. Getting very good results with DKC now with the beam sharpness settings around 0.75.

[MajorPainTheCactus]

Yes but your GFX card/integrated GFX may be able to do that upscale effectively free for you - just as your TV effectively upscales free for you. All we’re saying here is to try and use a different upscaling algorithm (a cheaper one that may even incur less latency for you).

Also beware of using a horizontal sharpness value of below 1. I was going to remove it as the maths breaks down below one and you get sharp drop off points. Imagine each pixel is your screen and you try to see something off screen - that’s effectively what you’re doing with a sharpness value below 1. It might work up to a point because some values are still on screen but when they fall off screen you’re into fantasy land.

Just to add vertical sharpness doesn’t suffer from this problem as CRTs are a inherently horizontally biased display technology.

[Cyber]

Here’s something else to look forward to for next year:

OLED TV Battle in 2023: TCL RGB OLED vs QD-OLED vs LG WOLED!

Let’s hope TCL gets it right in terms of subpixel layout.