Sony Megatron Colour Video Monitor

RetroArch Additions Shaders
#723

Yeah I’m not sure I buy into this theory - there’s really little difference between this shader and displaying a pure red or a pure green or pure blue screen - just one out of four pixels are black in the horizontal direction is the only real difference.

I’m not sure there’s anybody that says don’t display a pure colour screen due to risk of burn in. In fact we’re turning off the majority of sub pixels so it’s even more unlikely to raise temps as to damage displays. LCDs in particular are lit by comparatively large lights behind them so they don’t really have the control to damage individual cells as in the above description.

In your particular case youre using an SDR IPS display and I’d imagine its pretty much impossible to have burn in on that display. Even an OLED probably wouldn’t have problems.

As to why you’re getting flickering I’m not sure - do you get flickering if you display a red, green or blue screen? My IPS is fine at displaying all those patterns that you linked so it might be hard for me to correctly diagnose this - it does feel like a display level issue. I presume you’re using the SDR version in all this?

#724

Here’s an example of a paused screen where it’s particularly apparent, note that most of the screen is black here.

PXL_20220326_180657129
PXL_20220326_1806571294032×3024 3.27 MB
This is the crt-sony-megatron-sony-pvm-2730-sdr preset with the TVL set to 1000. It’s less obvious on 800, but about the same on 600. It doesn’t seem to happen at 300, presumably because the chunks are so big at that point that the signal isn’t spiking back and forth as rapidly.

I’m not sure if it happens during movement, whether it’s less obvious or the fact that it’s not still actually prevents it. I don’t actually use this shader since my resolution isn’t appropriate for it, but this flickering was something I noticed when testing it out and playing around with the settings so I just wanted to corroborate what BBB was saying.

If you give me a preset with some added bloom or lower mask strength or whatever I can try it out and see if it still happens, but there’s probably someone far more qualified to look into it further.

(Also it’s only letting me attach one image per post and they still require approval for some reason, don’t mean to shit up the thread and doublepost…)

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#725

I said image retention, not burn-in. It has nothing to do with displaying a section of pure color, or temperatures. It’s about staggered pixels, especially on still/constant images (like when paused), and it’s more apparent when only some portions of the screen are filled.

Here’s an example of how displaying one of those patterns on only a portion of the display can affect the rest of the line that it’s on: (Only the green portion is the actual pattern)

PXL_20220326_125415941
PXL_20220326_1254159414032×3024 3.32 MB
This is not uncommon, it happens on both of my completely different monitors, and I’m sure many others.

I’m also not suggesting that this shader causes the same issue or behaves in the same way, just that staggering pixels can absolutely cause monitors to do weird shit.

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#726

sorry, i approved those in reverse order

#727

Ah ok you’re using the 1000TVL because you’re on a 1440p display which makes sense as that gives roughly 660TVL. Ok so that makes a little more sense in terms of a high frequency pattern. The 1000TVL option uses a magenta-green mask as in there are no pixels that are off on a pure white screen just alternating magenta green lines. This may play havok with any image processing the screen is doing and I’d just turn off any image processing.

However fundamentally I’m not sure LCD technology has any inherent problem with display alternating colours - we all used to use Windows not too long ago where 1 pixel lines were all over the place for instance. I do see terrible problems occur when chroma compression is employed to compensate for low bandwidth. I note your display is a 1440p with 165Hz refresh rate - are you running it at that hz and res? Mind you that might explain the green image in the bottom photo but not the flickering.

I’d like to try and repeat that green pattern my end as I have a few monitors here - what exactly are you doing in the bottom picture?

Can you see what is actually flickering? Is it the whole screen or is certain areas or at the pixel or sub pixel level? Is it irregular or is it a fizz? Does it go away when you display a full white screen with that preset and 1000TVL option set (test 240p Suite has one)? Another thing you could try is the black white mask on option 3 for CRT type.

Although you could well be right and what you see above is the same problem, BBB is also using a 4K HDR screen and will undoubtedly be using the 600TVL mask which is very different to the 1000TVL one youre using and then add on to that he’s using a TV and youre using a monitor which are too very different beasts and the end result is probably who knows with the myriad options at play.

I’d like to repro this and I think I may have just the monitor bear with me - its certainly displaying my shader as green through Parsec but I thought that was just Parsec compressing the image but maybe it isn’t. I’ll have a play around with it.

#728

So I’ve added a ‘crappy TV’ preset that has a AEG CVT 4800 VT simulation with a NTSC composite signal simulation (basically vanilla NTSC-adaptive .slangp).

I played around with all the settings in NTSC adaptive and the defaults seemed good enough with a tweak to slangp scaling.

Anyway most of the details are over on this thread:

but here’s a video of the results here (as always play full screen and 4K to see the details properly):

4 Likes
#729

Hi @MajorPainTheCactus , I’m interested to verify that RA’s output is utilizing my screens 10-bit color depth.

My screen is in HDR (400) with 10-bit color output. (verified with control panel settings).

I enabled logging in RA with write to file, and after loading the HDR PVM 2730 preset, the log file shows:

[INFO] [Vulkan]: Using BGRA8888 format.
<...>
[INFO] [slang]: Using render target format R8G8B8A8_UNORM for pass output #0.
[INFO] [slang]: Using render target format A2B10G10R10_UNORM_PACK32 for pass output #1.
[INFO] [slang]: Using render target format A2B10G10R10_UNORM_PACK32 for pass output #2.

Just to verifiy with you, is the above confirmation of final RA output being in 10-bit color depth?

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#730

Good question! I’m not sure where or when the first message is printed out but it would be wrong if RA is using a HDR swapchain (back buffer) at that point. It’s difficult to know whether it’s talking about the swap chain format as well. It should be saying A2B10G10R10 for a HDR format - let me check my output and I’ll confirm (how do you enable logging to a file btw)

All the slang messages are correct however

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#731

The logging is enabled under “Settings -> Logging -> Logging Verbosity = ON”, and in that menu also set “Log to file = ON” (edit this option only shows when Logging Verbosity is set to ON).

The log files can then be found after a new start and quit in the Retroarch -> logs folder.

2 Likes
#732

Hi all. I tried this shader on an LG OLED C6, but it didn’t look so good. The brightness actually seemed lower than sdr mode…

Should i have the input set to something special? Pc or console mode? I set the games mode in the hdr settings. Should i have windows 11 set to hdr before setting retroarch to hdr? What should i set luminance to in the shader settings? Rtings claims everything between 126 and 600+ for this tv. And should i play with the nvidia control panel settings?

Thanks for the help.

1 Like
#733

Yes this is a common finding when the HDR isn’t working - is it all washed out too? So definitely have HDR on in Windows 11. You should see the RA menu’s glow when HDR is enabled in RA (make sure to have D3D11/D3D12/Vulkan selected then go to Settings->Video->HDR) and then you can start using this shader. Next set the peak lumiance to your TV’s HDR peak luminance that RTings states - I’d got for 650. Then tweak paper luminance until it looks ‘right’. Do let me know how you get on!

#734

The flickering on my qn90a is more a buzzing and not BFI. I’m not sure a camera would capture it. It’s almost like the emulated phosphurs become unstable but it doesn’t happen on OLEDs. That all sounds dramatic but It’s not a huge deal. Just something interesting to note. It happens at 600TVL and 1000TVL but not the other two settings.

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#735

Hi @BendBombBoom ok so that’s interesting - I’m wondering what could be causing that as those two settings use two very different types of mask and yet the 300 and 800 masks don’t exhibit the issue.

I know I’ve asked you a lot now but there definitely isn’t any image processing going on? I think there are modes that you have to set the TV into to stop any image processing. Something like game mode I seem to remember reading. Just a thought.

Does this happen only with certain colours?

#736

Thanks for the help, HDR worked and continues to work after disabling in windows. Although whenever I turn it on in RA the screen is blank until I quit and restart. Also if I go windowed briefly then it’s black when I return to fullscreen so have to quit out and restart again. Is this common?

The image with HDR still isn’t great and I think my TV just isn’t up to it. Firstly, shaders aside, when I load a game with HDR the colours are much more ‘muddy’, sort of grey/brown compared to SDR. Is this normal? If not, I guess any shaders applied on top will suffer too. With Megatron running the image is very dark at full brightness. Pushing paper luminance to around 1000 brightens things up, but is very washed out. If I use CRT mask 3 the image pops much more and I can set paper luminance lower, but it’s less authentic looking (not terrible from a distance though). I feel like the WRGB structure and/or only 650 max luminance are holding this shader back a lot on my TV. Cheers

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#737

Hi, can you share your settings for this please? Such as hdmi input label, TV picture settings profile/edits, gfx control panel settings if any? shader settings. Thanks

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#738

That behaviour isn’t right - it should blink out as it changes the swapchain but nothing more severe - trying using the d3d12/D3D11/Vulkan i.e another hdr capable driver to the one you’re using. All the muddy colours really does sound like HDR isn’t working - if you flick over to SDR in the shader params does it instantly look right? If yes then you definitely don’t have a HDR swapchain.

#739

You are not alone - I get the same black screen behavior when turning on HDR in Retroarch with my LG C1. It seems that anything that causes RA to loose focus when HDR is on causes the black screen issue and RA needs to be restarted.

1 Like
#740

Thanks again for your help. The colours do look a little better when i calibrate the luminance in the hdr settings in retroarch, but not as vibrant as sdr. The paper luminance was very low, but i believe the shader overwrites these so i didn’t want to touch them. Hdr is on using vulkan, the whites are brighter, but the shader doesn’t look right. Like there’s a translucent filter. It looks like the max brightness is too low then there’s the oled subpixels too . I’ve seen decent results on a C1 tv though. I’ve tried changing the hdmi input to pc mode, games mode, normal etc and all look different, but none correct. Also tried using a dp to hdmi, but then my max resolution was 1080p. Strangely, dx11 and dx12 don’t have a hdr option at all. Only vulkan does…

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#741

Yeh, RA goes windowed for a second when turning on hdr so has to refocus. Have you managed to get this shader looking ok on your c1?

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#742

Yes this definitely signifies something is up with your HDR. D3D11 and D3D12 are the gold standard when it comes to HDR in RA in Windows. They’re checking for proper support and sending metadata back to the TV etc.

You’re right to ignore the Settings->Video->HDR luminance and contrast settings when using Megatron as it bypasses those as it’s a proper HDR shader.

So my question again is when you toggle Quick Menu->shaders->shader parameters->SDR | HDR do the colours instantly fix themselves in the shader (but it looks a bit dark)? Let me know what option has the right colours - HDR or SDR - SDR will be darker though but thats to be expected.