I disabled dithering on Apple silicon + Introducing Stillcolor macOS M1/M2/M3

DisplaysShouldNotBeTVs

tmfd Go to Stillcolor at the top left of the Xcode file tree, then "Stillcolor" under TARGETS, then Signing and Capabilities. If you see stuff like "App Sandbox" and "Hardened Runtime" here, there should be trash can icons at the top right of each of them. Click the trash can on both so all you're left with is one tab called "🔻 Signing". This will remove the app sandbox and allow those properties to be changed.

Then, just comment out the alert.runModal() line that shows the alert box that says "Stillcolor Issue". It will say "invalid argument" some times but then end with a "successful" anyway in the console after it tries a couple of times, so even though it makes it "look like" it didn't work, it does make the change as long as app sandbox is disabled and you eventually see "returned 0 -> (os/kern) successful" in the Xcode console.

For example, here's what I get in the console when I disable VUCEnable:

(Disabled = box checked in the Stillcolor menu bar BTW)

AppleCLCD2 service: 310b
AppleCLCD2 client: a17b
IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
Failed to set VUCEnable to false IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
AppleCLCD2 service: 310f
AppleCLCD2 client: a17f
IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
Failed to set VUCEnable to false IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
AppleCLCD2 service: 3113
AppleCLCD2 client: a183
IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
Failed to set VUCEnable to false IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
AppleCLCD2 service: 3117
AppleCLCD2 client: a187
IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
Failed to set VUCEnable to false IORegistryEntrySetCFProperty returned -536870206 -> (iokit/common) invalid argument
AppleCLCD2 service: 311b
AppleCLCD2 client: a18b
IORegistryEntrySetCFProperty returned 0 -> (os/kern) successful
VUCEnable set to false

It says "failed" a bunch of times, but eventually ends with successful, and the VUC change works in the end.

tmfd

DisplaysShouldNotBeTVs Thanks! That seems to be it working as you described now, will continue testing.

Donux

Folks, do not waster your time. These dithering setting tweaks pretty much do nothing, or some very minor superficial stuff. It must be hardware related. You can tweak, you can install Asahi, all you do is change software, while hardware will remain the same. Also I have put myself into bad position by taking m2 airbook 13 for little workcation as only machine, and then when work duties came in I was torturing myself really badly with it. My conclusion software tweaks do nothing, only superficial stuff. And also limit your time with this machine as much as possible, because if you have it brand new you kind of excited with all the bells and whistles, but then after some time, it will create some real problems for you.

NewDwarf

Donux

Donux These dithering setting tweaks pretty much do nothing, or some very minor superficial stuff.

I cannot agree with this conclusion. The hardware has specific set of capabilities (like temporal dithering) which can be controlled via software. We can write at the specific control register in the graphics card to enable/disable dithering. The legal interface for this is the IORegistryEntrySetCFProperty() API.

aiaf

Donux I don't deny that you are facing eyestrain issues with the internal display, even with software tweaks. But one of the primary functions of software is to control hardware, in fact that's the point of a display driver, and what we're doing here is modifying display driver settings to change the behavior of a display.

DannyD2

Donux I don't agree. Stillcolor has made a huge difference for me on my M2 Air 15. I've probably used my computer more in the last few days than I've used it in the last month; the display feels so comfortable now. It seems like there are more issues to investigate on the MBPs because the display on the MBPs is more complex, but on the Airs this is definitely a game changer.

Donux

NewDwarf Ok. I do not want to kill a drive to get a working solution, lets try everything possible. Just saying for anyone who have high workloads, do not over-commit to alpha solutions 🙂 as it might hurt a bit 🙂

aiaf

martin Try Pastebin or Gists

martin

aiaf Should I send it to you in a private message with the pastebin link?

aiaf

NewDwarf many thanks for your boot-args work too, it really lay the ground for a software solution! Do you have dumps or anything from reversing these drivers? Doesn't have to neat, just a gist or some hint on which frameworks to look at?

aiaf

DisplaysShouldNotBeTVs IOKit on iOS is as you mentioned a private framework, I've read that IOMobileFramebuffer is even more locked down there because of frequent vulnerabilities. You create C header file with the function declarations you wish to use and load the framework dynamically.

Check https://github.com/guoxuzan/IOKit/ and https://forums.developer.apple.com/forums/thread/719564

aiaf

DisplaysShouldNotBeTVs this is all very exciting! Thanks so much for trying these out, I've added these options in my own build and will release it soon. VUCEnable is particularly interesting because it changes the quality of banding- the bands are less regular and less logical so to speak? I'm not sure if this is says anything about dithering yet though.

uniformity2D is also very obvious. It disables the vignette effect.

Can you make a list of all the options you tried. There are still a ton of other options on the IOFramebuffer object, I will diff those soon.

In other news I got my Carson microscope and will start recording befores and afters.

Blooey

aiaf There are still a ton of other options on the IOFramebuffer object, I will diff those soon.

Just in case you missed the tool, there is a GUI wrapper on IOReg. It is called IORegistryExplorer, and is included in Apple's Additional Tools For Xcode package on the More Downloads Page. When you run IORegistryExplorer, type IOMobileFramebufferAP into the search field, then View menu select Browser View.

Pretty great for this work, since it shows the properties update in near real time, so you can see the enableDither property toggle to false in real time when enabling Stillcolor. It also lists many other properties available on IOMobileFramebufferAP, and how they are changing over time and with different system settings.

aiaf

Blooey interesting findings, thanks for testing! One thing is sure is that display manufacturers cannot be trusted with this information. We have to perform independent testing. I got my Carson microscope today and will do my own.

aiaf

DisplaysShouldNotBeTVs do you reckon uniformity2D is a hack to lessen the appearance of backlight bleed?

Maxx

@DannyD2 What kind of symptoms you get from displays and are you sensitive to PWM. Are there some displays that you can use?

I'm asking to understand if you have the same situation as I have, so I could also get M2 and test stillcolor. I dont' want to do it right away, as I ve tested about 20 laptops and screens and TV's and I don't want to waste my time

NewDwarf

Maxx Mackbook Air 15'' M2 is PWM free. So, by disabling the dithering we totally get rid (I hope) the main issues which cause problems. This can explain why MBA 15'' M2 becomes comfortable to use.

At the same time, many MBP models are NOT PWM free and even if dithering is disabled, one can fill discomfort.

…to measure the screen PWM, I made the special adapter based on the photoresistor. I plug it to the oscilloscope to measure the PWM value. It can measure up to 200 kHz.

photon78s

Blooey

I have recorded some probably tens of dozen's of videos by now with different internal and external panels. I may have observed pixel inversion on a intel iGPU T480s laptop running a known dithering free OS/driver combination (windows 10 1809 with no intel graphics driver installed). Columns of pixels simultaneously gradually increase and decrease in brightness. Is this pixel inversion? In my other videos of other panels, the dithering flicker is with different pairs/groups of rgb pixels scattered at different places. The frequency may also be different and the groups pixels in a column are not exactly flickering in sync.

Videos labeled dithering or pixel inversion (recorded all on 60Hz panel with 240 fps camera played back in slow-mo at 30 fps). Also, best to download the video not view them within dropbox.
https://www.dropbox.com/scl/fo/47fw3ygxkxaq78ul0j19i/h?rlkey=a2fvkmlujs2m9tkmdw59ujwvl&dl=0

The videos labeled dithering are probably a combination of dithering and inversion.

This may also be informative:
https://ledstrain.org/d/2669-pixel-inversion-and-temporal-dithering-might-be-using-the-same-mechanism/2

Update: now not so sure if you can tell the difference. Probably most you could tell at a glance is that temporal dithering combined with inversion causes the flickering to be more apparent.

aiaf

Blooey thank you, it's very helpful.

deepflame this is great! I'm glad to hear it's working for you. Re. iOS, I don't see why a similar solution wouldn't work if indeed dithering is toggled via the same mechanism. We just need to get there. I think @DisplaysShouldNotBeTVs is working on something.

asus389 this is the million dollar question. Waiting for someone with a true 10-bit display to try it out and measure things. If it indeed turns off dithering in response to a 10-bit panel, that would be amazing. In fact, you don't even need a 10-bit display, TRUE 8-bit (which seems tricky to find also) with Stillcolor should suffice.

jordan which ViewSonic model is that? They released a new VX2781-4K-PRO-6 with IGZO IPS panel in China a few days ago which claims to be true 10-bit!

madmozg the mechanism is the same across all M-series Macs. It disables the enableDither property and with that the GPU/DCP stops applying temporal dithering to the pixel buffer. Try using an sRGB color profile and see if that makes an additional difference. Did you enable Launch at login? The app needs to run every time the computer starts.

NewDwarf @Blooey explained it very nicely. The main thing to note is that Apple's GPU/DCP applies temporal dithering to the pixel buffer way before it even touches your HDMI/Thunderbolt port. That's why you can capture all of this with an HDMI capture card.

deepflame

@aiaf just wanted to say that I am so thankful for all your work. I have an M1 MacMini that I used on and off but figured lately that I could not use it anymore because of eye strain. StillColor makes it usable for me again. This is really awesome.

Today I was at a computer shop and tried StillColor on an M3 MBP and M2 Air. Both were better with StillColor installed ( the MBP even better with ProMotion and Truetone off ).

Now I am thinking to get an MBP myself again. That would be an Apple laptop after several years that I could use again. That would be a dream come true.

Would be great if this also worked for iOS. I had an iPhone 11 with iOS 16 as my daily driver. I could use this without issues. However when I told my iPhone 13pro that I use to test new features to update to iOS 17.4, my iPhone 11 also upgraded without me doing anything. Now the screen is way worse and I cannot roll back the upgrade. So I am hoping this can be fixed with this method somehow.

Thanks again for all your efforts. Yes, please make a donation page or something that people can express their gratitude.

NewDwarf

deepflame The main problem of modern iPhones is low frequency PWM. More likely, modern iPhones don't use temporal dithering at all.

DisplaysShouldNotBeTVs

deepflame I'd recommend the M2 Air or M3 Air instead. The M3 Pros and other Pros with XDR displays have a lot more quirks with their screen (for example, they have 10,000 individually controlled backlights behind the screen that all basically use different PWM frequencies per zone to dim at independent amounts) that we don't know everything about or how to solve yet.

I've already discovered two additional properties unique to the Pros that are needed in addition to disabling dithering to further improve the screen output, there are a lot of extra things the Pro displays do that are currently unknown.

Meanwhile, M2 Airs have a simple, traditional edge-lit LCD for the most part with a PWM-free backlight, and Stillcolor can resolve a very significant amount of issues with their display output.

twomee

NewDwarf they are. I sensitive to temporal dithering and know the pain of it. I feel it also in iOS too

jordan

NewDwarf I mean if dithering can be turned off on LCD iPhones that would be huge. They also do make LCDs for OLED iPhones which I've seen some have super high PWM which is good. How do you know modern ones don't dither ? I'm sure they do. Dark mode, reduce whitepoint,and night shift all seem to trigger dithering which was noted on flickersense.org

I'm sure they are using the same pixel color flicker technique on modern iPhones too.

DisplaysShouldNotBeTVs

NewDwarf They do I can clearly see and feel moving static patterns / dithering on my iPhone SE 2 (LCD) screen (it has iOS 17.2.1) and gradients also look more smooth than they "should" on my 14 Pro with iOS 16 too.

Not sure about the OLED iPhones (since it has backlight precision per pixel, it might be using that instead to achieve greater color depth i.e. different PWM frequency per pixel), but for the LCD, it's so obviously using temporal dithering to my eyes. I have an iPhone 6 and iPhone 7 with the same resolution and size screen that feel so much more comfortable than the SE does.

However I have some older devices that don't dither or dither less, like an iPad 6 with an earlier version of iOS 15 that shows way more banding on gradients, shadows, and transparency effects.

NewDwarf

jordan I mean if dithering can be turned off on LCD iPhones that would be huge.

LCD iPhones, like iPhone 11, iPhone SE 2020/2022 are PWM and dithering free! This means is nothing to disable there. iPhone 12 and newer are all OLED.

jordan They also do make LCDs for OLED iPhones which I've seen some have super high PWM which is good.

That is not true. In the best case, PWM does not exceed 1 kHz. This frequency is too low for the PWM sensitive persons.

jordan I'm sure they are using the same pixel color flicker technique on modern iPhones too.

…I am not sure 😉

Just checked youtube videos. They confirm that the temporal dithering is not present on the OLED iPhones.

https://www.youtube.com/watch?v=ieCT17IZp2E // iPhone 14 Pro

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