upward auto-exposure / eye-adaptation glsl shader SDR (temporal stable)

[geextahslex]

First of all a big shout out to Jules-A, he gave the tip that storing history in a user shader was actually possible, without it there would be no stability in the image.
After searching for an "auto-exposure / eye-adaptation" glsl shader here finally is one for SDR. This shader only brightens the image, it doesn't darken it. But you can expand it and add features on top of it.
You get two shaders. One main shader, and the 2nd one is the same but with added meter/stats (overlay at the top of the screen), so you can actually see what is happening under the hood. This will make it easier to set it up to your liking.

1. Keep in mind to change values in both shaders, not only in the main one, because then you get wrong Meter/Stats data.
2. Don't run accidentally both shaders at the same time, always switch between them to see the stats.

Enjoy it, have fun :)

Meter/Stats:

Green Bar=raw avg brightness input
Yellow Bar=how much of the effect is applied

Keybind (input config):

toggle shaders on/ff

o change-list glsl-shaders toggle "~~/shaders/auto_exposure2.glsl"
p change-list glsl-shaders toggle "~~/shaders/auto_exposure3.glsl"

here you can control the value of EFFECT_START from 0.5 to 1, this can be applied to the other variables (this is a template)

w cycle-values glsl-shader-opts EFFECT_START=0.5 EFFECT_START=0.55 EFFECT_START=0.6 EFFECT_START=0.65 EFFECT_START=0.7 EFFECT_START=0.75 EFFECT_START=0.8 EFFECT_START=0.85 EFFECT_START=0.9 EFFECT_START=0.95 EFFECT_START=1
s cycle-values !reverse glsl-shader-opts EFFECT_START=0.5 EFFECT_START=0.55 EFFECT_START=0.6 EFFECT_START=0.65 EFFECT_START=0.7 EFFECT_START=0.75 EFFECT_START=0.8 EFFECT_START=0.85 EFFECT_START=0.9 EFFECT_START=0.95 EFFECT_START=1

Config:

Speed of adaptation (lower value=slower, higher value=faster)
(line 107) float alpha = 0.005;

Strength of brightening effect (Max Exposure)
(line 64) #define MAX_EV 1.5

At which point effect starts brightening
(line 51 - EFFECT_START) 0.9

At which point effect reaches maximum
(line 67) #define EFFECT_FULL 0.20

Performance:

How many samples taken for averaging frame brightness
(line 17) const int N = 16;
You can increase that number (32, 64 etc.) to get more accurate results, but keep in mind that a higher value can decrease performance depending on your specs/machine/current load

16x16=256
32x32=1024
64x64=4096

Installation:

1. put files into your "shaders" folder (MPV\portable_config\shaders)

2a. run always via mpv config "MPV\portable_config\mpv.conf" (Don't run both at once)

glsl-shader=~~/shaders/auto_exposure2.glsl
#glsl-shader=~~/shaders/auto_exposure3.glsl

2b. or keybind via input config "MPV\portable_config\input.conf"

o change-list glsl-shaders toggle "~~/shaders/auto_exposure2.glsl"
p change-list glsl-shaders toggle "~~/shaders/auto_exposure3.glsl"

Invert Shader/"Night mode" (Bonus):

This can help in specific conditions like Night Vision or very bright skies
off

on (invert-hard)

Download GLSL Shader:

Update: added 2 invert shaders
auto_exposure has now a more finetuned look
shader.zip

old:
auto_exposure.zip
auto_exposure3 (no stats)
auto_exposure2 (with stats/meter)

[Jules-A]

I don't know if you checked the 2nd file I sent but you'll probably want to have separate speeds or logic for dark to scenes with bright areas (that may still be partially a dark scene) so it doesn't flashbang you.

[geextahslex]

I only checked the shader you posted first. I actually use a shader that inverts highlights, so it's kinda a "dark mode"
Bright skies are killing my eyes ^^'

[Jules-A]

Ah, the first one was super broken, the 2nd one actually functions as an auto-exposure shader since I tested it and adjusted it so it wouldn't flashbang.

[geextahslex]

I mean I have only seen the color changing at the top of the screen. The more choice the better.

[Jules-A]

I mean I have only seen the color changing at the top of the screen. The more choice the better.

Huh? I'm referring to the post where you were asking for help, I posted 2 files, the first one was just the first output to demonstrate that it was reading but as an exposure shader it was broken. The second contained fixes to actually make it fuctionable and avoid flashbangs.

[natural-harmonia-gropius]

This uses 16x16 points of the image to calculate average brightness, which is insufficient. Secondly, I don't believe real-time measurement solutions can truly eliminate flicker. A feasible approach is to convert the video to HDR as is, then use a solution like Dolby Vision/HDR10+ to generate dynamic metadata, ensuring the generated metadata is smooth, merging it into the HDR version of the video, and finally playing it using HDR-Toys.

[Jules-A]

This uses 16x16 points of the image to calculate average brightness, which is insufficient.

Yeah, definitely, even the 32x32 in the example script I posted wasn't really enough but did make a big diff over 16x16. You could do some sparse sampling and downscaling the image first to avoid large sampling costs. I didn't notice any flickering but I guess that would also depend on how how it's set up, like FPS and speed being too fast that it's not temporal enough.
Still, I don't think converting files before using is much of a solution for most people. Forcing HDR on the file at runtime maybe but I still haven't managed to get any decent results doing that...

[geextahslex]

Don't worry, I have used this shader already for multiple hours. There is no flickering, it's super stable :)
You can increase 16N to any number you wish, no worries. This value works to keep it as lightweight as possible.