Sony Megatron Colour Video Monitor

[MajorPainTheCactus]

@barack-ojama and @scarf so Ive managed to repro both your problems.

A bit of background I have 5 displays I use to test on: Eve Spectrum (4K IPS HDR 700 nits), Samsung S95B (4K QD-OLED HDR 1000 nits), BenQ EW3270 (4K VA 300 nits), Dell XPS laptop (4K IPS SDR 600 nits), OnePlus 8 Pro mobile phone (1440p AMOLED SDR 1400 nits).

Ive gone into the 240p test suite and selected the grey ramp test pattern which shows two black to white and vice versa gradients across the screen. When I adjust the paper white and peak luminance and then the CRT gamma values to get a perfect black to white gradient on my BenQ because its so dark I have to have the paper white value right up to the peak luminance (of the monitor which is basically 250ish nits) and thus I need to compensate with a really high gamma value.

This I think gives the washed colours on that display which is what scarf is seeing when I look at the pure red, green and blue test screens. Lowering the paper white value and reducing the crt gamma seems to fix it in my limited testing at the cost of brightness.

On my Samsung S95B because its so bright I can have paper white around 200-300 nits (peak at 1050 nits) and a crt gamma of 2.22 giving perfect blacks and pretty bright whites and thus all the colours are vivid. Im yet to test the other screens I have - Ill first give you a report of my mobile phone.

Long and short is to play with those three settings and Ill have a think to see if there is anything I can do to help matters.

[MajorPainTheCactus]

So my OnePlus Pro 8 which has a whopping 1400 nits in SDR has a perfect gradient with SDR gamma set to 2.4 and CRT gamma set to 2.22. It also has very vivid colours. An amazing screen if Im honest.

[barack-ojama]

Changing those settings doesn’t have much of an effect for me unfortunately. I think it might just be the panel type itself; perhaps something about LGs OLEDs specifically (BGR pixel structure or something maybe?). I plan to get a new TV this year so I’ll end up playing around with this shader more when that happens. Big thanks to everyone for all the help.

[Cyber]

@barack-ojama

I think it might just be the panel type itself; perhaps something about LGs OLEDs specifically (BGR pixel structure or something maybe?).

Sony Megatron Colour Video Monitor

@datjocko seems to have gotten pretty decent results. Maybe they can share some settings? Or maybe even @Wilch?

Sony Megatron Colour Video Monitor

CRT-Sony-Megatron-Sony-PVM-2730-HDR HDR On in RetroArch/Windows, HDR On in Preset RWGB (OLED) Subpixel Layout, 300TVL, NTSC-U [20220922_051024] Note: the dark grey horizontal line is from the shader parameters menu. [20220922_050923] RWGB OLED Photos: Samsung Galaxy A71 Camera: Pro Mode, ISO 100, WB 5000K, Aperture Speed 1/60, Manual Focus. Oh yeah, it’s fixed alright! Next stop, verifying if the Slot Mask presets work fine with OLED and if not designing one that does?

Sony Megatron Colour Video Monitor

Here’s an iPhone photo of the new OLED mask using a third party app without AI processing. I think it looks quite good. This is on an LG OLED42C2 [IMG_2042]

[Scarf]

Are the SDR versions showing perfect blacks for you guys without LG CX? It really doesn’t make any sense to me how the SDR version can have different black levels on different TVs.

[Wilch]

My oled seems fine with this shader (LG C2 42 inch).

It supports full 4:4:4 at 4k, not sure about the C1 or CX, but here’s my settings:

TV: Hdr Brightness - 100%, Dynamic tone mapping - HGiG, Video range (black level?) - auto, BFI - off, Input label - PC, HDMI deep colour - 4k (on)

Nvidia control panel: (desktop in sdr), 10 bpc, Colour format - rgb, Dynamic range - full,

Megatron: Sony pvm 2730 hdr, Peak luminance - 720, Paper white - 250, Subpixel layout - rwbg

I don’t have hdr on in Windows 11, just RA using vulkan. I had to enable hdr in Windows first when using directx in RA.

Here’s some photos: (colours look more saturated in person)

[Scarf]

Here’s my picture with the same settings on RetroArch/LG CX.

EDIT: A better picture where Link is not in the dark:

[Wilch]

I just checked 240p test suite and realised the blacks are grey here too (using the shader). If i set the black level to low or raise gamma it improves. Need to tweak this some more. If i set black level to low without the shader i lose some colour gradients as expected, but enabling the shader returns them. The tv panel reports rgb 10bit.

Also some presets including default cause the blue bar to lose about 6 gradients regardless of black level

[MajorPainTheCactus]

Thats almost certainly the gamma settings (which includes those luminance values when using HDR). Have you definitely put paper white right down - a third of peak say and then play around with the CRT gamma (not the sdr gamma). Every single one of displays will show black at some setting of those three values.

The only other options are your TVs settings artificially making it grey or the black isnt black and is some very dark grey (you can test this by turning off the shaders and just screen grabbing the window and checking the values).

Failing that its all very odd.

[MajorPainTheCactus]

Try playing around with CRT ‘Gamma’ in the shader parameters as well. You definitely should be able to get pure blacks at the cost of brightness.

[MajorPainTheCactus]

Thanks for these settings @Wilch - its difficult to diagnose without the TV. It does look a little washed out though still - is that just the camera as you mentioned?

[MajorPainTheCactus]

Is this any better for you?

[Scarf]

My LG CX is properly calibrated so I doubt it’s the TV settings. Every other CRT shader has pitch black blacks and so did the Megatron shader before one of the updates that changed something.

The last Link to the Past pictures I posted also had greyish blacks. But this is not a big deal since now I know how to fix it.

[MajorPainTheCactus]

Is that in HDR that all the other shaders have pitch blacks - if so what are the gamma values and what settings do you have in the RA->Settings->Video->HDR menu?

Thinking about this I am going to check a few things as really black should be black always as its zero but there are cut offs in the rec.601/709 gamma standard that treats very darks and blacks differently and this could be where the dark greys are coming from with high gamma’s.

[MajorPainTheCactus]

Just also to add you can have more normal gamma values on low brightness displays with other shaders as they are inherently brighter. However you should definitely be able to get black black regardless in the Megatron - it will just be much darker overall.

[Scarf]

No, I’m talking about SDR since the SDR variants of Megatron have this same issue with raised blacks. You can see this immediately on an OLED in games that have a black background in the intro screen (or like in Super Metroid where the Nintendo logo at the start has a black background) since the background is not the same color as the black bars on the TV in 4:3 aspect ratio.

[Scarf]

Ok, changing SDR Display’s Colour Space to r709 gets you perfect blacks on the SDR variants it seems.

[MajorPainTheCactus]

Ok so what did you have it on - PAL/NTSC/NTSC-J? There maybe a bug here or its just part of the standard.

[Scarf]

The default setting which is sRGB.

[MajorPainTheCactus]

Thats odd - this off of my phone using sRGB (you might need to turn up the brightness of your screen to full to properly see it). The blacks look black to me - see the magic meter.

SDR Gamma: 2.4, CRT Gamma: 2.22