I have a wide gamut screen and I have basically always had some banding. I am mostly using Debian, sometimes some flavour of Arch. However, recently I started EndeavourOS live with the Nvidia driver and I noticed that there is no banding.
Now I played around with the dithering settings in nvidia-settings but they do not seem to change much.
Also, if I install EndeavourOS, the banding is back.
What is the trick here? Why is there no banding on EndeavourOS-Nvidia-live?
Btw, there is also banding on Windows.
Thanks in advance
Anna
Well, one more thing: although my screen allegedly can 10bits, I use 8/24 bit output.
Ok, just had an idea: is it possible that the live system runs in 10-bits-mode? I mean everything looks normal…
it looks like banding. It is not visible on normal photos, just gradients, e.g. desktop wallpapers.
I don’t know, I set Debian to 10 bits and the banding was still there. Really wonder why there is no banding on EndeavourOS live. Until now I lived with the banding, I thought it could not be fixed but apparently that’s not the case. However apparently there is no way to find out what is actually going on because all the diagnostic tools are missing on the live system and they cannot be installed because it’s a rolling distro and wants to install all the other updates and and requires a restart, and every change is lost on a live system after a restart. Well at least I don’t know how to do it.
Anyway, the dithering options in the Nvidia driver don’t seem to do anything.
Could it perhaps be that it’s the actual desktop wallpapers being quite heavily compressed, leading to banding being visible on the ones which show gradients?
I mean the banding is present in the live system when I don’t choose Nvidia at system start. I think it is some mysterious Nvidia driver setting.
Well, I also installed a community edition of EndeavourOS on a USB stick that was using Wayland (Qtile), and the banding was there, too.
it’s a png - it’s the same wallpaper that EndeavourOS live without banding is using.
The banding is very disturbing in the upper left quarter of the wallpaper.
That to me suggests that it’s dithering actually present in the pixels of the image file, rather than banding artefacts caused by nividia drivers / hardware issues.
Heres a screenshot of the wallpaper, zoomed in on Gimp, on Mint 20 Cinnamon.
There is hardly any banding when I download them and view them in an image viewer but there is some bending when I view then in a browser on the website.
No change looking at the background wallpaper? That suggests it’s dithering actually in the pixels which makes up the background wallpaper, and not actually anything to do with hardware settings.
When you boot the live system, there is an option in the boot menu to start the system with the Nvidia drivers. Nvidia drivers are closed source. Nouveau has nothing to do with Nvidia. I supposed if there is the option to boot with the Nvidia driver, Nouveau is not active.
The live system can be started with Nvidia, but if you actually install the system, you need to install the Nvidia driver after the installation.
Maybe it would be worth testing this on other Arch based systems.
Banding issues are best tried to be replicated in the same software .
Start gimp, create an empty 8bpp image and fill it with a straight gradient from black to white. See how it looks on both systems .
Switching to 10bit display output would do nothing if the image in question (a wallpaper ) is 8bpp to start with.
Maybe if the driver would be trying to dither over it , but god I hope not … They would ruin any kind of purpose for having a good studio style screen.
Most times these banding effects are causes by
display profiles trying to fix some contrast issue
effects being applied to an image
other settings like RGB levels for the HDMI connection or stuff like that (causing contrast adjustments ).
Basically anything that tries to enhance contrast , be it on purpose or as a side effect .
Oh , and of course it can be the monitor with some ‘dynamic contrast’ setting , but I assume you have disabled all that kind of stuff and are not changing monitor settings between tests.
As we know from Play Raw entries, the zoom level can affect how we perceive the image. Sometimes edits have halos at certain zoom levels but look great on the screen of the submitter before uploading. Sometimes it could be the resizing (people complain about that regarding RT or dt once in a while).
There is also the drawing issue, which could perhaps be a driver / software compatibility issue. See my G’MIC discussion on Summed Area Tables (aka Integral Images) where non-float (32 bit) rounding becomes a problem for smooth gradients.
