I disabled dithering on Apple silicon + Introducing Stillcolor macOS M1/M2/M3
DisplaysShouldNotBeTVs I can agree with you. Thanks for the feedback, you should create a new topic with those assumptions also, so other people could find your info easily. 
Btw I went yesterday to apple and did some testing for iMac M3, and I was not able to find any flickering, I need more time to do more tests before posting anything solid here.
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async I'm 90% sure that I could do 6-bit with AW EDID Editor some time ago, however when trying recently the OS seemed to ignore it, like it does with certain things. I use this for 10 to 8-bit successfully. Figured it was either due to Sonoma upgrade, or that it simply didn't renegotiate or something.
See my post here for my own recent experiment involving an Intel Mac Pro, macOS High Sierra, an NVIDIA GPU, and a 6-bit+FRC display. While subjective, I definitely felt a difference (worse flickering, unstable image) when overriding the display EDID from 8-bit color depth to 6-bit color depth. Furthermore, other than while on the lock screen (and only on one display… weird), the effective depth did not appear to be reduced, so I figured all this did was traded the display's FRC dithering for temporal dithering by the operating system or GPU.
EDIT: Sorry, I just saw that you replied to that post, and therefore already saw it. Interesting that our experiences differ, though.
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MBP mini led is still a shit show. Tinkered a ton with it today. Especially when increasing the brightness above stock and changing some flags you can both see the individual backlight leds turn on and off in a pattern, as well as color artifacts to the side of them. There is also this banded blob that changes size around the bright cursor based on how close it is to the leds, so while moving the cursor it keeps scaling up and down, and that part is significantly delayed compared to the leds.
Also it's almost impossible to make sharp contrasted areas like black and white feel solid. After trying a bit I actually think I got a wavy pattern that matched the placements of the backlight leds in my peripheral vision.
Most scrolling gives significant flickering as well. So far only Edge seems to handle it ok. Most measurements done are without any movement, but it is just as important how it behaves when you actually use the machine.
Obviously this is less of an issue when not using extreme adjustments, but it still proves that there are a lot of things going on that manipulates the image far away from the actually moving pixels.
Tried to capture some videos of this, but I have to find somewhere to upload it.
One of the issues is similar to this: Samsung Odyssey G9 Backlight bleed (youtube.com)
Carson microflip at 100-200x magnification. To clarify, it is getting hard to distinguish if what I'm seeing is pixel flicker or just artifacts and noise from my Samsung 240 fps phone camera. On crappy displays and monitors, the pixel flicker absolutely obvious and "undulating". With this display, it's actually a very good sign that I'm having difficulty making clear interpretations.
On pixelinversion.com and I did not see flicker on the first page of tests. Also a very good sign.
photon78s Opple waveform charts at 100%, 50%, and 25%
when I measure my 16" 2k 120hz laptop, I got results where Opple measure PWM freq equail to Screen refresh rate
At 120hz - 123hz PWM
At 60hz - 61hz PWM
At 50hz - 55hz PWM
At 48hz - 48hz PWM
I think, Opple dont show PWM coz it synchronise with refresh rate. And as lower brightness, as more noise in screen, so its hard to measure proper freq with Opple.
Look at your 25% measurments, dont you think its 8ms period and 120hz PWM?
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Hmm... it is a fixed 60hz refresh rate screen correct for this model (no ProMotion, no miniLEDs)? Normally, you would think that refresh rate has nothing to do with the flicker of the backlight LEDs. I also film at 240fps (not with microscope) and don't see any backlight flickering. I agree on the noise as factor in general with any measurement. I also agree to not pay too much to the frequency numbers from the Opple and simply just get a rough sense of the waveform and how that might correlate with subjective comfort. Stay tuned for results with the oscilloscope and photodetector.
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async It would be really interesting to do the same on an M2 Touch Bar with a bad screen.
There's not really a M2 Touch Bar with a truly "bad screen" / unusable screen IMO, since even my first one with the worse panel was still more usable than every other Apple Silicon Mac. It was more of just visible defects, yellow tint, and screen uniformity issues which made me return that one.
(The "worse" panel had long empty sections of 00000000 in the panel ID and serial number dump, the "amazing" panel has a fully filled out serial number without any empty sections.)
However, since I still have the M1 Air for a little bit longer, I will dump ioreg on there — since I consider the M1 Air very uncomfortable (relative to any M2 Touch Bar Pro).
The M1 Air's panel is a lot different, flickers on camera (in the same way the M2 Air does) and is way worse.
Will be interesting to see if the ioreg has any significant difference.
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photon78s Edit: While I did not detect any PWM on the backlight at 240fps or at 1/24000 shutter speed photos the opple shows PWM flicker at lower brightness settings (see below). More testing on that later with oscilloscope waveforms.
Yep this lines up with the notebookcheck review (which is good to know, since sometimes notebookcheck can be really inaccurate)
When I say the M2 TB Pro screen is "flicker-free" I mean it's possible to make it flicker-free, i.e. at higher brightness levels.
Also, I actually did use the computer for a while at lower brightness levels yesterday, and whatever high frequency PWM is there still does not affect me nearly as much as the really annoying low frequency PWM-like flicker on M1 Air and M2 Air.
However, PWM can still be avoided at high brightness!
(Lots of people think that is true with other Macs too, but two 2015 Intel Macs I tested actually also show PWM-like flicker on dark grays in 240hz slow-motion even at max brightness!
M2 Touch Bar Pro is the only MacBook I've tested that just doesn't have this issue at all. This is what makes it so unique!)
And with Stillcolor, it's possible to dim the screen through color overlays or color table adjustments (e.g. with BetterDisplay) without introducing temporal dithering.
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photon78s Can you upload a video of the "pixel flicker" you captured vs. the other laptops you recorded that have much worse pixel flicker?
photon78s Stay tuned for results with the oscilloscope and photodetector.
interesting fact: I have measured my old laptop display and Opple say no PWM (straight line), but I found panel datasheet where PWM is in 200…1000 hz range. I think it non-economical for laptop factory to set panel and replace build-in PWM backlight to backlight with LEDs which supports analog-type (voltage reducing) brightness adjustment
to get proper RGB pixel flickering video, you need at least 1000+ fps camera with ability to shoot at high ISO with 1/1000 shutter minimum, to capture at least 1000hz flickering frequency, or you get "smooth" results
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photon78s It's still there but if this is in fact pixel inversion or some kind of FRC
I suspect that it's just pixel inversion because I don't seem to be getting any FRC or temporal dithering symptoms with this laptop at all.
These are the benefits that I get using the M2 Touch Bar Pro:
- My eyes don't feel like they get "stuck" on sections of text (I don't have to put energy in to "unstick" them)
- Mouse cursor changing state (e.g. from arrow to resize cursor) does not cause the mouse to "pulse in and out of focus"
- My eyes don't randomly, involuntarily jump to "flickery" patches of the screen (I can stay focused on one area I choose of the screen for a really long time, even while typing)
- I am able to focus even on whitespace, with the whitespace feeling huge and expansive — without having the immediate urge to jump back to content
- Wallpapers don't distract me from window contents, I can focus on the very edge of a window without "automatically" drifting my focus into the wallpaper.
All of these I have much worse experiences on in temporally dithered screens (and I have problems with some of the above on the M1 Air too, so maybe the M1 Air still uses TCON FRC in some way?)
But on the M2 TB Pro, this all works so good for me, which is why I suspect whatever micro pixel flicker you are noticing is not temporal dithering.
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Sampled on the same or close enough patch on blooey's test chart. Lenovo Legion Pro 7i at 60hz versus M2 MBP TB. I also suspect it is only showing pixel inversion differences at this point. The 7i is running ditherig.
Warning! Please do not click the link to watch the videos if you are or suspect you are sensitive to visible flicker!
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photon78s Woww, that's an amazing difference compared to the 7i.
The 7i is definitely and obviously showing temporal dithering — but on the Touch Bar MBP, there's sooooo much less that I suspect that all that we're seeing there is mostly pure camera noise.
It doesn't seem to have a really noticeable pattern (compared to the 7i where dithering is clearly visible).
For example, I actually get something that is reminiscent of the remaining "flicker" on the Touch Bar MBP when recording even printed words on paper on my iPhone 14 Pro, which obviously shouldn't flicker, so I bet most of that is just camera noise.