New HDR Settings

[Retro-Nerd]

should be disabled" is not something I would ever give as advice. It will violate your warranty and it will increase the likelihood of burn-in occurring.

Never seen any signs of burning-in after 3 years. But yes, it's not suggested for everyone. You have to exactly know what you are doing with your TV. With ABL it's a misearable OLED experience for sure. Anyone remember the crappy "House of the Dragon" episode where your couldn't see a thing? ABL makes it even worse. The dimmed image makes it a plain audio drama.

[thisisamigaspeaking]

This was never meant for a real HDR mode, with a texture/layer you know from modern games/movies. It's just a forced "HDR on" to get full luminance of your display, nothing else. Natrox did a good job in converting the colors, this is better than the RT5x can do it. And as many times explained, it's only use is to counter a too dark image when one use a CRT filter with scanlines and masks.

Try video_saturation=70 maybe this is colorwise closer to what one would expect. Look at my pic above. There is no black crush or highlights clipping. A bit colorful, but this is tweakable.

I wasn't able to find any hue or saturation setting that fixed this for me. Also there were some issues with gain in different cores that I wasn't able to solve (galaga need a bunch of gain to even look vaguely correct).

If this is mapping to either Rec.2020 or DCI-P3 it seems like it should be possible to get an exact representation of the colors. If it's not mapping to those color spaces, what do the options for each do exactly?

I'm willing to fiddle with this more, just not sure what I should be doing. It's a bit of a pain to have to log in an edit the ini and reboot for every adjustment. I am always curious to play with and test HDR though since I have a different display than most people (everyone else seems to be using LG OLEDs).

Are there any test patterns for MiSTer that will display RGB gradients or RGB & gray? Thought I'd seen something like that but I couldn't find anything searching on google.

[Retro-Nerd]

You could try the 240p Test Suite for that.

https://artemiourbina.itch.io/240p-test-suite

[dmckean]

Yes, something like ABL should be disabled with a service remote control.

"should be disabled" is not something I would ever give as advice. It will violate your warranty and it will increase the likelihood of burn-in occurring.

ABL is actually there to protect the power supply since it's undersized on these sets and is unable to handle lighting up a full screen at max brightness for more than a few seconds. It shouldn't increase the likelihood of burn-in much. It does violate the warranty though (rightfully).

[FoxbatStargazer]

I didn't think it was even possible disable ABL, unless there's some service menu for it. Note this is a separate thing from auto-dim or energy saver, which might not be a bad idea to disable.

[Retro-Nerd]

You need a cheap service remote. The "instart" button is the magic key. I meant ASBL/TPC, not ABL.

https://www.amazon.com/de/dp/B09TG4D2LV/

[thisisamigaspeaking]

You need a cheap service remote. The "instart" button is the magic key.

https://www.amazon.com/de/dp/B09TG4D2LV/

You can also do it with a Windows app called ColorControl.

[Retro-Nerd]

Do you confuse here something? In which way could a Windows app access the service menue of an LG TV?

edit: Ah, found it. Nice.

https://www.reddit.com/r/OLED_Gaming/co ... erm=sbords

edtit2:

This is even easier.

There is even simpler solution. You can access LG service menu even from TV itself. I fixed APL on my C1 without remote and apps. From WebOS browser go to http://webosapp.club/instart/ agree and proceed. Voila, you are in service menu.

[thisisamigaspeaking]

This is even easier.

There is even simpler solution. You can access LG service menu even from TV itself. I fixed APL on my C1 without remote and apps. From WebOS browser go to http://webosapp.club/instart/ agree and proceed. Voila, you are in service menu.

Be careful what third party websites you direct your TV to... Obviously they know some hacks.

[KennyL]

Ok so Natrox already uploaded a bunch of gamma profiles for dealing with dark low-mid tones in Mister discord days ago.... I sure wasted bunch of time making my own but at least I was on the right path. Discord being discord, I can't cleanly link to them here so just go look for them in there if you're interest... ¯\_(ツ)_/¯

[Natrox]

The colors look more off than if for example I set my Mac to Rec.2020 but don't set the monitor to Rec.2020 - which should be equivalent to what is happening here, right? Is the color space conversion definitely correct?

It is, we're using the matrix from the official programming guide.

Mapping to these color spaces does not mean we're able to cover the gamut. Hence, DCI P3 will look better for most as it's a smaller space to cover.

Also of note is that this chip was made without HDR in mind - it's technically not supported at all on the HDMI version that is being used. Other HDR hardware will probably have HDMI that is HDR-aware, so to speak.

If we were to try and get a better color representation, we would have to get into 3D LUTs, which is not feasible on the FPGA - especially not together with cores.

The RetroTink 4K may be able to do a better job since it'll be dedicated to processing rather than also running games.

[Natrox]

Ok so Natrox already uploaded a bunch of gamma profiles for dealing with dark low-mid tones in Mister discord days ago.... I sure wasted bunch of time making my own but at least I was on the right path. Discord being discord, I can't cleanly link to them here so just go look for them in there if you're interest... ¯\_(ツ)_/¯

I'm out at the moment but I'll upload them later. In essence they are just the pure gamma presets but for sub-100. The files have a simple mathematical formula to generate them, you can recreate them in a few minutes.

[KennyL]

I'm out at the moment but I'll upload them later. In essence they are just the pure gamma presets but for sub-100. The files have a simple mathematical formula to generate them, you can recreate them in a few minutes.

Hey sorry for going grumpy mode, I'm just not too hot about how a lot of good stuff just evaporate away in discord...

Anyway, I'm having a lot fun with HDR. Things look really good by applying gamma lift and scanlines. Here is a comparison on my LG C2 (my phone changes color so please look it as relative comparison. All these look very bright and less saturated in person.)

mister_hdr_240p.png (619.11 KiB) Viewed 12565 times

First is unfiltered with HDR=2, video_brightness=50, video_contrast=45, and video_saturation=85. Low-mid is too dark and saturated.

Second is with gamma lift filter. Face is still overblown but looking much better in person with less saturation and less crunched.

Last is with scanlines. Skin tone is looking really nice and everything feels all buttoned up together. I'm pretty happy to play like this.

I have a question for you about highs getting clipped on LG C2. In discord you suggested to someone to try hdr=3. I tried it but highs are still clipped. But applying scanlines unclips highs (reason why face is looking more correct on above picture.) Something is off that C2 can't handle it with auto HDR tone mapping. Is there some kind of MaxCLL? Maybe C2 can't see meta data that it can use to set its display range properly. HDR being highly dependent on capabilities of displays, HGIG could be helpful to match content max brightness and display max brightness. But of course that's beyond the scope of Mister. Is it possible to add some kind of faux HGIG? Or some kind of clipping point adjustment.

[Natrox]

I'm out at the moment but I'll upload them later. In essence they are just the pure gamma presets but for sub-100. The files have a simple mathematical formula to generate them, you can recreate them in a few minutes.

Hey sorry for going grumpy mode, I'm just not too hot about how a lot of good stuff just evaporate away in discord...

Anyway, I'm having a lot fun with HDR. Things look really good by applying gamma lift and scanlines. Here is a comparison on my LG C2 (my phone changes color so please look it as relative comparison. All these look very bright and less saturated in person.)

First is unfiltered with HDR=2, video_brightness=50, video_contrast=45, and video_saturation=85. Low-mid is too dark and saturated.

Second is with gamma lift filter. Face is still overblown but looking much better in person with less saturation and less crunched.

Last is with scanlines. Skin tone is looking really nice and everything feels all buttoned up together. I'm pretty happy to play like this.

I have a question for you about highs getting clipped on LG C2. In discord you suggested to someone to try hdr=3. I tried it but highs are still clipped. But applying scanlines unclips highs (reason why face is looking more correct on above picture.) Something is off that C2 can't handle it with auto HDR tone mapping. Is there some kind of MaxCLL? Maybe C2 can't see meta data that it can use to set its display range properly. HDR being highly dependent on capabilities of displays, HGIG could be helpful to match content max brightness and display max brightness. But of course that's beyond the scope of Mister. Is it possible to add some kind of faux HGIG? Or some kind of clipping point adjustment.

No worries. I made these gamma filters really quickly, mostly to test, but I want to get them included with the distribution.

You may be onto something with the HGIG and MaxCLL stuff. I have also observed some bright things being clipped (if not using scanlines). I know it's not the matrix doing that as I've set it up to have leeway, so it may be something else.

I'll have to study the infoframe used for HDR. This is the part that is not my original work - as specified in the PR I took an old branch from wickerwaka and added controls and integrated it. I'll have to comb the spec and see what can be done.

The suggestion of hdr=3 was just to rule out the color matrices. Mode 3 does no color space conversion and thus any clipping or crushing has to happen elsewhere. Mode 3 also looks pretty terrible.

Thanks for giving it a go.

[FoxbatStargazer]

I have a question for you about highs getting clipped on LG C2. In discord you suggested to someone to try hdr=3. I tried it but highs are still clipped. But applying scanlines unclips highs (reason why face is looking more correct on above picture.)

This is 100% ABL/APL etc like I said. (more details way over my head here. Beyond any power saving/anti-retention features, there's a max sustained wattage you can put through any OLED panel, and that max is often lower than blasting the entire screen at max brightness. So making half the screen darker with scanlines is going to open up more of that brightness budget for the brighter half. This really comes down more to your TV than anything Mister can do, aside from pulling down the overall brightness output from Mister.

[boilop]

On my professional HDR monitor (BenQ PD3220U 32), it really looks incredible. I have a sony PVM next to it and it's striking how close we are getting now...

Thanks a lot for building this feature!!

[thisisamigaspeaking]

The colors look more off than if for example I set my Mac to Rec.2020 but don't set the monitor to Rec.2020 - which should be equivalent to what is happening here, right? Is the color space conversion definitely correct?

It is, we're using the matrix from the official programming guide.

Mapping to these color spaces does not mean we're able to cover the gamut. Hence, DCI P3 will look better for most as it's a smaller space to cover.

Also of note is that this chip was made without HDR in mind - it's technically not supported at all on the HDMI version that is being used. Other HDR hardware will probably have HDMI that is HDR-aware, so to speak.

If we were to try and get a better color representation, we would have to get into 3D LUTs, which is not feasible on the FPGA - especially not together with cores.

The RetroTink 4K may be able to do a better job since it'll be dedicated to processing rather than also running games.

Ok so this is what I'm looking at that made me feel the colors were off, this is from Minimig.

hdr-compare.png (632.93 KiB) Viewed 12437 times

The blue bar in the HDR version is significantly more red. Is there any setting that will fix this without making the gray in the background off color as well? This may not look like much of a difference in this photo but it is quite dramatic on the whole screen with my eyes instead of a camera...

It occurs to me this could be a problem with my monitor's calibration rather than the MiSTer output, I didn't think about that. I'm not sure if it has a separate LUT for each color space, but there definitely is separate for SDR and HDR. I've never noticed HDR being miscalibrated but I will check it when I have a chance.

The problem I was having in Galaga went away and I'm not sure what caused that. The reds were cutting out entirely before. Now it looks ok, perhaps not side by side but looking at it on its own one wouldn't notice a problem.

[KennyL]

This is 100% ABL/APL etc like I said. (more details way over my head here. Beyond any power saving/anti-retention features, there's a max sustained wattage you can put through any OLED panel, and that max is often lower than blasting the entire screen at max brightness. So making half the screen darker with scanlines is going to open up more of that brightness budget for the brighter half. This really comes down more to your TV than anything Mister can do, aside from pulling down the overall brightness output from Mister.

I got you about scanlines' affect on ABL but I think C2's clipping problem is tone mapping issue.

No worries. I made these gamma filters really quickly, mostly to test, but I want to get them included with the distribution.

You may be onto something with the HGIG and MaxCLL stuff. I have also observed some bright things being clipped (if not using scanlines). I know it's not the matrix doing that as I've set it up to have leeway, so it may be something else.

I'll have to study the infoframe used for HDR. This is the part that is not my original work - as specified in the PR I took an old branch from wickerwaka and added controls and integrated it. I'll have to comb the spec and see what can be done.

The suggestion of hdr=3 was just to rule out the color matrices. Mode 3 does no color space conversion and thus any clipping or crushing has to happen elsewhere. Mode 3 also looks pretty terrible.

Thanks for giving it a go.

After messing around with C2 more, it looks like your HDR peak brightness is indeed too high for C2 to handle.

C2 and other LG OLED TVs has secret menu you can access by going to Pictures setting menu and press 1113111 on remote. Turn off Dynamic Tone Mapping option before doing this. (Images are dim because I had to lower TV brightness and phone's exposure way down to capture the gradient.)

lgc2-mastering-peak.jpg (48.53 KiB) Viewed 12349 times

On 240p Test Suite Color Bars pattern, highs are clipped with Mastering Peak set to Auto (default value.) Highs are unclipped when set to max 10000 nits. It's also clipped if I go next tick down at 4000 nits so basically it looks like Mister HDR is sending out 10k peak brightness.

lgc2-mastering-peak-compare.png (253.28 KiB) Viewed 12349 times

I gotta fault LG for not able to properly resolve sources outputting 10k nits. It would be great if you can add option to set source peak brightness. 10k for future proofing, 4k for newer ultra bright TVs, 1000 for most of current TVs, and 600 for PC HDR monitors.

[thisisamigaspeaking]

I know it's nI gotta fault LG for not able to properly resolve sources outputting 10k nits. It would be great if you can add option to set source peak brightness. 10k for future proofing, 4k for newer ultra bright TVs, 1000 for most of current TVs, and 600 for PC HDR monitors.

Yeah it would be nice to have that setting. Some monitors offer different modes for that, straight mapping to its range (so that 10,000 nits or whatever is mapped linearly at the top of its actual brightness), clipping at the top of its range (everything above 1,000 nits or whatever it is stops at 1,000), or on a curve (progressively higher values get closer and closer to its peak).

Most (or all) PC HDR 600 monitors don't really do useful HDR. They don't have the contrast ratio to do it or local dimming zones. Basically any HDR monitor for PCs is going to be 1000+ nits. Earlier LG OLEDs were not that high in brightness but they do have good contrast ratios of course so they look decent enough in HDR.

[KennyL]

Yeah it would be nice to have that setting. Some monitors offer different modes for that, straight mapping to its range (so that 10,000 nits or whatever is mapped linearly at the top of its actual brightness), clipping at the top of its range (everything above 1,000 nits or whatever it is stops at 1,000), or on a curve (progressively higher values get closer and closer to its peak).

Most (or all) PC HDR 600 monitors don't really do useful HDR. They don't have the contrast ratio to do it or local dimming zones. Basically any HDR monitor for PCs is going to be 1000+ nits. Earlier LG OLEDs were not that high in brightness but they do have good contrast ratios of course so they look decent enough in HDR.

Yeah totally. I expected C2 to do this mapping but apparently not. I have no idea at what brightness it hard clips. Very annoying. HDR is so needlessly complex and messy....

[Asteld]

Clipping in HDR space is normal, at least for consumer displays. Dolby Vision movies are mastered at something like 10000 nits, which is something no(?) consumumer display can show. Manufacturers, like LG, have to make some decision in how to handle this deficiency. One option is to 'compress' the brightness range into the ±800 nits that the e.g. the LG C2 can display. Except for the highest of highlists, most content is still mastered around SDR-ish brightness levels of 200 nits. A simple compression of 10.000 nits mastered content into a 800 nits range would therefore result in very dark images.

The solution at least LG has chosen is to clip the highlights. It simply does not matter much if a highlight like the sun is displayed as a single very bright area, as opposed to some spots that are very very bright, next to spots that are incredibly ultra bright. A max brightness sun will suffice.

This is why the concept of 'paper white'.matters in HDR space. You set the level of 'SDR max brightness'. at e.g. 200 nits and ideally the display then shows highlights as bright as possible (within reason for the particular display).

Obviouslsy this does not work when translating SDR content into a HDR format, as your 'SDR max brightness' also contain the highlights that you ideally want to display at HDR levels. The "Auto HDR".settings of Windows, xbox and LG's own TV's rely on (AI) algorithms to properly detect which details from the SDR source should be highlighted. The Mister cannot and should not attempt this, but instead optimise its output for CRT simulation.

The current mister implementation of showing #ffffff as max brightness is dubious. I suspect no one actually wants to be blasted with max brightness for everything that is white on the display. I have not checked how the colour adjustment settings are implemented, but I suspect the current setings mess with the SDR output, before translating that to HDR, destroying a lot of dynamic range in the colours in the process.

In addition, the current settings are not sufficient for TV's from e.g. LG, since they set the max brightness of HDR apparently at 10000. This is not so much a problem for HDR content, but it does mean you cannot simply map SDR content to the entire HDR brightness range, since that results in (severe) clipping.

It will be some time before we get there, but I do think this new addition is a great step forward for Mister.

[Natrox]

Hello all, some major news.

I researched HDR infoframes more and figured out that the one currently in-use is incorrect for BT2020.
This explains color reproduction issues, as well as the incorrect whitepoint.

I have constructed a new infroframe and made a PR for it: https://github.com/MiSTer-devel/Main_MiSTer/pull/721

Among the color space value fixes, I have also corrected the max luminance. The exact values:

• Max luminance: 1000cd/m2
• MaxCLL: 1000cd/m2
• MaxFALL: 250cd/m2

I have carefully tested the new metadata and I am happy to report that most of the original issues reported are gone.
Clipping was not observed.

Regarding MaxFALL, the exact value is not super important. In essence, it tells the display to expect at most 25% of max luminance in a frame of video data.

For those of you who use hdr=2, I recommend you try out hdr=1 again after this PR is merged. Please turn off the color controls and turn off the gamma filter in "Video Processing".

The Mister cannot and should not attempt this, but instead optimise its output for CRT simulation.

The MiSTer could do something similar actually. Dynamically setting luminance information based on the current frame is possible.
To do this you could repeat this procedure every second or so (to avoid killing the CPU):

• Access the scaler buffer which has the raw video output.
• Linearly read it while keeping track of maximum luminance (in 0.0 - 1.0 space), minimum luminance and average luminance.
• Scale the maximum luminance with the display luminance configured. E.g. if the peak in the image is 0.5, you would set a max luminance of 500 (0.5x1000). This will be used for MaxCLL as well.
• Use the average luminance to calculate MaxFALL. This variable is the average luminance of the scene, so we can calculate it. Just as with MaxCLL, scale the average with the display luminance.
• Send adjusted HDR metadata infoframe.

This should, in theory, result in HDR that adjusts itself to the content on screen. I have not tried it yet as it did not seem necessary at this point.

On my professional HDR monitor (BenQ PD3220U 32), it really looks incredible. I have a sony PVM next to it and it's striking how close we are getting now...

Thanks a lot for building this feature!!

On 240p Test Suite Color Bars pattern, highs are clipped with Mastering Peak set to Auto (default value.) Highs are unclipped when set to max 10000 nits. It's also clipped if I go next tick down at 4000 nits so basically it looks like Mister HDR is sending out 10k peak brightness.

Thank you both for testing and researching. I did not realize it was sending 10k cd/m2!
I hope things look better with the new metadata that uses 1000cd/m2. I don't think it is necessary to make it configurable yet - monitors that can handle more brightness will probably scale the luminance.

[Natrox]

Hello all,

The PR with updated metadata has been merged. Additionally, I have submitted a PR containing an implementation of HLG HDR if the hdr option is set to 3.

It was mentioned by Mathieulh as a potential better fit for MiSTer as it's designed to be backwards compatible with SDR. I have added it and am happy to report that it looks like SDR but brighter. :V

If the other two modes don't produce a satisfactory result, try hdr=3. I recommend using no color controls for this mode. Not all TVs support it, but anything modern (2017-) should have it.

Here is a photo taken by Mathieulh comparing the MiSTer in HLG mode with his Trinitron CRT:

20230102_143202.jpg (901.22 KiB) Viewed 11761 times

Once these changes have been released officially, I hope people will enjoy them. I'll continue to try and improve the experience where possible.

[Retro-Nerd]

Awesome update. Now everything looks perfectly fine out of the box. No matter if the game has a more darker or brighter palette. You have to tweak nothing. Many thanks for the update.

[mathieulh]

Here are some additional pictures using HDR=3 with HLG HDR on a LG CX with Motion Pro (BFI) to medium and OLED light to 50 at 1440p, side by side with a Trinitron WEGA CRT

For this to work using HLG HDR you need to make sure Dynamic Tone Mapping is on in your TV options (you are relying on your TV to make the color conversion from SDR to HDR for you), or your colors will look off.

20230102_160026.jpg (722.95 KiB) Viewed 11759 times

20230102_160149.jpg (1.05 MiB) Viewed 11759 times

LG CX:

20230102_160122.jpg (2.32 MiB) Viewed 11759 times

Trinitron CRT:

20230102_160127.jpg (1.91 MiB) Viewed 11759 times

Here are my filter settings:

20230102_153230.jpg (788.79 KiB) Viewed 11759 times

[dmckean]

Fantastic work!

[Neocaron]

damn that look freaking good and it's a picture :0

[SuperSpongo]

Exciting stuff!

[KennyL]

This is superb! Bravo!

I'm testing the build Natrox posted in discord, hdr=3 HLG, default ini settings. Brightness is much higher than sdr on my C2 while keeping good color. Highs are not clipped with or without scanlines. Everything looking nice and bright with or without scanlines and shadowmasks on. Saturation is also higher than sdr at video_saturation=100 but it looks pleasant to me, not off color like before. I like high saturation in general so this is great. Basically now I can adjust saturation without colors looking way off.

Hdr 1 and 2 options are obsolete for me now. Colors still look off and highs are still clipped on my C2 (better than before though.) But these problems don't matter to me anymore with HLG option. Great call on pushing in HLG @mathieulh.

C2 bfi took a major downgrade compared to earlier C series so it's dark and very flickery on all 3 hdr options.

[FoxbatStargazer]

The HLG looks superb on my C1. Just a little bit of pop without messing with the color balance or gamma. A+!