Since KDE plasma 6 with hdr support came out recently, I decided to check how some of the hdr tagged movies I’d watched previously look with that. I was surprised to see that they are rather dark, even in scenes under direct sunlight. I ‘tested’ the brightness by opening the movie in hdr and sdr at the same time and manually changing the sdr brightness to compare.
Most scenes, including those outside and in sunlight seem equivalent to 200 nits in sdr. Only highlights (like sky if the sky isn’t a large part of the shot, or glimpses of outside in indoor scenes) seem to reach 700-800 nits. I thought there was some kind of a baked in abl in the files, but then I found a scene (starkiller base firing in swtfa) that got more bright than the sdr brightness slider goes (while covering half the screen too), so that’s not it (Edit: I think this is an hdr to sdr mapping caused error. In some frames the laser becomes gray thus much darker in sdr versus hdr. In other frames 800-1000 nits seem right. Still the brightest scene I could find.). There seems to be a conscious decision to keep most scenes the same brightness
Are movies supposed to be like that? I’d think the cameras would capture the brightness accurately and that would be what you see with minimal modifications to it. What’s the point of hdr if there isn’t a brightness difference between a sunny scene and a cloudy scene? I mean, the highlights have a lot more detail instead of crush and that’s good… I’m pretty sure those that I’ve seen in the theather were not this dark in most scenes tho.
I’ve tried a few web-dls and blurays. They all seem to have this issue.
Increasing contrast from the player seems to work and I guess I’ll just find a good default for that and forget about it eventually, unless you have a suggestion. Expected more from the fabled hdr tho
Sorry if this doesn’t fit here
Edit: Bit the bullet and booted windows to analyse the files. They are indeed dim for my taste (due to having low max brightness and/or baked in abl), with high brightnesses only being used in highlights and the rest are 400-200 nits. Took some screenshots (they’re badly blooming since they’re sdr screenshots of hdr). The cursor is positioned on the sky in most and in a bright area in the rest:
I took another right before this shot while they’re still in the ship but forgot to save it. The tiny bit of visible sky was 600 nits in that shot, so I think this file does have baked in abl.
Star wars turned out to be pretty good with a 1000 nit target in general, but the desert is still dim for some reason (below 50 nits in this scene!)
Also tried spiderverse on suggestion. It wasn’t that bright but I think that’s fine for animation.
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Dumb question, but are you using a monitor that supports HDR? And is set to display in HDR?
I’m not sure how KDE handles HDR but if you’re looking at the SDR and HDR side by side, one of them is either displaying incorrectly or being converted on the fly to display in the other dynamic range.
Yep hdr is supported and enabled. Kde maps the sdr one to the hdr range like any other sdr display element, based on the brightness and color intensity you set in settings. That doesn’t give it more range and the crushed areas stay crushed, but that’s what happens on an sdr output too
I’m also using Plasma 6 to play games and watch movies in HDR and everything looks as expected.
What monitor/TV do you use? Did you install the necessary Vulkan layers? Do you use mpv with the correct parameters? Which movies/scenes?
You can try turning the SDR brightness all the way down and back up. If the brightness of mpv changes, you’re not running in HDR.
I did and mpv works in hdr. Monitor can show 1000+ nits according to test video.
I tried the star wars sequels (bluray), kenobi numeralj cut and dune 1 (webdl). Sw and dune’s desert scenes were where I felt something was off and after opening mpv without hdr found out that they were 200-250 nits bright. I could link the torrents if that’s allowed
Which monitor do you have? ABL is unfortunately fairly aggressive on OLED screens, e.g. my screen only reaches about 250 nit with a 100% white window, which is only 10-20 nit brighter than the maximum for SDR content.
I can’t speak for Star Wars but Dune is pretty bright so you might just run into your monitors ABL very easily. You can test by making mpv really small against a black background and then maximizing. If the image gets dimmer you’re getting limited by ABL.
You might want to grab a 4k remux for something like The Greatest Showman or Spider-Man: Across the Spider-Verse to benchmark with. They have a lot of colorful but dark scenes to really bring out the HDR highlights.
Monitor doesn’t have abl. I booted windows to analyse the files and they are dimmer in general than I’d hoped for. See the edit of the post
For games I was trying to launch steam in gamescope but launching just the game didn’t work neither, so I guess that’s nvidia
BTW how did you get the games to work? Gamescope is incredibly unstable for me. If it doesn’t freeze immediately then it either doesn’t change focus to the launched game or freezes on launch. Tried without it but then xwayland eats the hdr and it comes out horrible. Is it nvidia incompatibility?
I just built the Vulkan layer and gamescope from git and then started my native Steam installation normally. Then I just set the launch parameters to
ENABLE_HDR_WSI=1 gamescope --hdr-enabled --hdr-debug-force-output --nested-refresh 165 --fullscreen --steam --output-width 3440 --nested-width 3440 --output-height 1440 --nested-height 1440 -- env ENABLE_GAMESCOPE_WSI=1 DXVK_HDR=1 DISABLE_HDR_WSI=1 %command%.Works pretty well so far but I’m on AMD.
Common OpenSUSE W, only ticked HDR in screen settings and everything worked
You didn’t need to install the vulkan layer and use gamescope?
Edit: if you use gamescope, do you have Nvidia?
Not at all, but i’m using AMD, it’s plug and play
I highly doubt it actually works if you didn’t install the vulkan layer. Does the sdr brightness slider have an effect on the game?
So I had that issue once, the solution in my case was to calibrate the HDR (not just on the TV), but my receiver and playback device too
Wouldn’t bad calibration affect the hdr and software-mapped sdr equally? As in if there was an issue that causes 300-600 nits to show up as 200 nits or something, wouldn’t that issue also be present in sdr content under hdr with brightness set to those values?
I’ll definitely try that anyways, ty
Ooooh I see what you’re saying…sadly, I have no idea. I’m not the most savvy guy with this stuff, but your situation sounded familiar. I hope you figured it out
I had the same issue in LibreELEC. I said fuck it and switched to windows for now. Works perfect.
Linux community has to work out the HDR kinks.
See the edit, this wasn’t a Linux issue
How does HDR work in KDE, without it being supported by Wayland?
In my understanding hdr is mostly supported in wayland (the core parts of it anyway) but it’s not finalised so it remains largely unimplemented. Kwin itself can only output hdr to the monitor but can’t get hdr video from programs due to a lack of vulkan support (?). There’s a patched vulkan layer to bridge the gap.
I don’t think that’s the issue but I guess it could be. I’ll try an hdr brightness test video and compare it to the kwin managed sdr brightness slider to see
Edit: Yup it works correctly
Edit 2: I think the vulkan requirement might be just for it to work with hardware acceleration
Not an Expert in consumer hdr. What you want to calibrate isn’t contrast or brightness but gamma curve.
Tried increasing gamma but it lightened the darks too much so I thought contrast looked better. If I don’t end up calibrating icc or if I don’t like the result I’ll probably give up on any pretense of accuracy and just settle on some combination of contrast/gamma/brightness that looks good.
