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M1 Mac External Display - Fuzzy Fonts & Colors - YPBPR vs RGB

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The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
I have two (a bit older) DELL U2713H. One connected over usb-c -> DP the other HDMI (2.0a). Both were blurry with Big Sur, but did no notice the color output). After some updates everything looked fine on my "main" screen (connected over usb), the second one had and still has the issue with YPBPR. After editing the plist they are both sharp and show RGB.

The only issue I have left over:
I use a second laptop connected to my main screen over HDMI. When I change sources there is no picture. I have to physically plug out and in the usb cable, then it works again.

It is very annoying. A guy in a German Apple Partner store annoyed the hell out of me with his inability to follow simple technical thought. Now have a call scheduled with Apple. Lets see if there is some other solution available.
 
Aggedor said:
I guess I'll have to get used to it! Must admit, I am not noticing any difference with regards to font sharpness. Or... maybe that's my eyesight? My display is set to "looks like 2560 x 1440" (middle scale option).
Click to expand...
Or more likely reason is that there is no difference in font sharpness. That's because if YPbPr is running in 4:4:4 chroma subsampling it is pretty much the same as RGB in that. Only if monitor defaults forcing overscanning and/or 4:2:2 or 4:2:0 chroma subsampling difference became very noticeable, or like in many cases peoples complaining about font sharpness are using non HiDPI monitors like QHD (2560x1440 native) panels where fonts will look terrible in default.

Anyway, if you are using your computer for any photo editing or such, it is advisable to get used to correct display profile with correct colors (or even better calibrate it with proper meter for accuracy).
 
0906742 said:
Or more likely reason is that there is no difference in font sharpness. That's because if YPbPr is running in 4:4:4 chroma subsampling it is pretty much the same as RGB in that. Only if monitor defaults forcing overscanning and/or 4:2:2 or 4:2:0 chroma subsampling difference became very noticeable, or like in many cases peoples complaining about font sharpness are using non HiDPI monitors like QHD (2560x1440 native) panels where fonts will look terrible in default.

Anyway, if you are using your computer for any photo editing or such, it is advisable to get used to correct display profile with correct colors (or even better calibrate it with proper meter for accuracy).
Click to expand...
Ah okay, interesting. Is there any way I can tell if my monitor is running 4:4:4?
 
For what it's worth I have the same Dell U2415 mentioned in the OP and just received my first M1 MBA today. I've been following this thread thinking I'd probably have to upgrade my monitor in short order but after a couple hours messing around with the new machine I upgraded to Monterey, plugged in the monitor with a Silkland USB-C to DP cable and everything looks perfectly fine to my eyes. No weird colors and fonts look every bit as sharp as they did hooked up to my old Air.

The OSD has the Input Color Format as RGB with YPBPR as the other option.
 
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0906742 said:
BitDepth also needs to be set to 8 (it is probably 10 for yPbPr, was on my machine).
Also make sure there are not multiple display entries in the file and change them accordingly if needed.
Also check location ~/Library/Preferences and in the ByHost folder for another plist file, which is user specific and overrides the other global one. And as I said, you have to reboot or at least log off/on to make changes effective.
Let me know if that helps.
Click to expand...
Hi, thank you for all your help so far, but BitDepth is already set to 8. There is no such file in ~/Library/Preferences and there is one in the ByHost directory, but with all the right values set, so I'm not really sure what else to do.
I'm also rebooting after every change.
Do you have any other ideas? YPbPr is causing very jarring flickering when displaying darker scenes/screens and that issue was more or less resolved (or at least a lot less pronounced) when I got RGB working.
Again, thank you!
 
Last edited:
gygaxmoment said:
Hi, thank you for all your help so far, but BitDepth is already set to 8.
Click to expand...
Did you also check all other values and made sure they are correct? Maybe you could post your plist file contents here and I could take a look at it?

There is no such file in ~/Library/Preferences and there is one in the ByHost directory, but with all the right values set, so I'm not really sure what else to do.
Click to expand...
Sorry, I was a bit vague in my post but I exactly meant ~/Library/Preferences/ByHost.
Also you need to edit values in the /Library/Preferences/ location which is global setting for, the one in ByHost is user specific.

I'm also rebooting after every change.
Do you have any other ideas?
Click to expand...

This is pretty much example what should be under LinkDescription for RGB.

<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>

In case your plist file sees your monitor multiple times and there are several entries beginning with LinkDescription they you should edit those too. Or maybe just delete both plist files and let OS recreate them again like I did and I got my display detected only one time in plist, but I guess that can pose danger causing OS not working, so if you test that DO IT AT YOUR OWN RISK AND MAKE BACKUP FIRST BEFORE DELETING THEM!!!

YPbPr is causing very jarring flickering when displaying darker scenes/screens and that issue was more or less resolved (or at least a lot less pronounced) when I got RGB working.
Again, thank you!
Click to expand...
Yeah, I know YPbPr can cause side effect you mention and I'm pretty sure that it the reason for why we see some people here complaining about seeing that flickering with their monitors using M1 based computer.[/QUOTE]
 
patsio said:
Just upgraded to Monterey 12.0.1 (mac mini M1) and RGB came back to my Dell U2721DE. I'm not sure about the fonts, looks sharp enough. Today, also, TinkerTool had a new update for macOS 12 compatibility, the font smoothing options are removed or i'm blind, why?!
Click to expand...
I haven't opened TinkerTool in a while, but just updated it to allow it to run under Monterey, and you are correct in that the font options are no longer there. I can only guess that Apple has changed the way they operate in Monterey.
 
0906742 said:
Did you also check all other values and made sure they are correct? Maybe you could post your plist file contents here and I could take a look at it?


Sorry, I was a bit vague in my post but I exactly meant ~/Library/Preferences/ByHost.
Also you need to edit values in the /Library/Preferences/ location which is global setting for, the one in ByHost is user specific.



This is pretty much example what should be under LinkDescription for RGB.

<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>

In case your plist file sees your monitor multiple times and there are several entries beginning with LinkDescription they you should edit those too. Or maybe just delete both plist files and let OS recreate them again like I did and I got my display detected only one time in plist, but I guess that can pose danger causing OS not working, so if you test that DO IT AT YOUR OWN RISK AND MAKE BACKUP FIRST BEFORE DELETING THEM!!!


Yeah, I know YPbPr can cause side effect you mention and I'm pretty sure that it the reason for why we see some people here complaining about seeing that flickering with their monitors using M1 based computer.
Click to expand...

Ok, I think I may have found one of the issues. I unplugged my second monitor, deleted the plist files and let them be regenerated by restarting and I'm unable to generate the LinkDescription section for the monitor I'm having issues with. I had two entries before, but it seems both of them were for my secondary monitor.
I've played around with more or less every setting I could think, but no LinkDescription section. Any ideas on how to get the LinkDescription to show up in the plist file for my main monitor?

EDIT: This is the generated file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>DisplayAnyUserSets</key>
<dict>
<key>Configs</key>
<array>
<array>
<dict>
<key>CurrentInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
<key>Rotation</key>
<real>0.0</real>
<key>UUID</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
<key>UnmirrorInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
</dict>
</array>
</array>
<key>Orientations</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<integer>0</integer>
</dict>
<key>Underscan</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<real>1</real>
</dict>
<key>Version</key>
<integer>1</integer>
</dict>
<key>DisplayUUIDMappings</key>
<dict>
<key>3DD7ACF4-ABD4-DA03-0F93-5A69417CA049</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
</dict>
</dict>
</plist>
Click to expand...
 
Last edited:
gygaxmoment said:
Ok, I think I may have found one of the issues. I unplugged my second monitor, deleted the plist files and let them be regenerated by restarting and I'm unable to generate the LinkDescription section for the monitor I'm having issues with. I had two entries before, but it seems both of them were for my secondary monitor.
I've played around with more or less every setting I could think, but no LinkDescription section. Any ideas on how to get the LinkDescription to show up in the plist file for my main monitor?

EDIT: This is the generated file:
Click to expand...
Probably easier to get that entry appear in plist is to toggle HDR mode on > off, that created it right away in my system that also had that line missing.

Also I'm not sure but I think just adding them manually in plist should work as well. Make sure you edit both plist files!
Below is example in RED what to add in your plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>DisplayAnyUserSets</key>
<dict>
<key>Configs</key>
<array>
<array>
<dict>
<key>CurrentInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>
</dict>
<key>Rotation</key>
<real>0.0</real>
<key>UUID</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
<key>UnmirrorInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
</dict>
</array>
</array>
<key>Orientations</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<integer>0</integer>
</dict>
<key>Underscan</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<real>1</real>
</dict>
<key>Version</key>
<integer>1</integer>
</dict>
<key>DisplayUUIDMappings</key>
<dict>
<key>3DD7ACF4-ABD4-DA03-0F93-5A69417CA049</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
</dict>
</dict>
</plist>
 
Last edited:
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0906742 said:
Probably easier to get that entry appear in plist is to toggle HDR mode on > off, that created it right away in my system that also had that line missing.

Also I'm not sure but I think just adding them manually in plist should work as well. Make sure you edit both plist files!
Below is example in RED what to add in your plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>DisplayAnyUserSets</key>
<dict>
<key>Configs</key>
<array>
<array>
<dict>
<key>CurrentInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>
</dict>
<key>Rotation</key>
<real>0.0</real>
<key>UUID</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
<key>UnmirrorInfo</key>
<dict>
<key>Depth</key>
<integer>8</integer>
<key>High</key>
<real>1440</real>
<key>Hz</key>
<real>60</real>
<key>IsLink</key>
<false/>
<key>OriginX</key>
<real>0.0</real>
<key>OriginY</key>
<real>0.0</real>
<key>Rotation</key>
<integer>0</integer>
<key>Scale</key>
<real>2</real>
<key>Wide</key>
<real>2560</real>
</dict>
</dict>
</array>
</array>
<key>Orientations</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<integer>0</integer>
</dict>
<key>Underscan</key>
<dict>
<key>F45E08B2-FFFE-4C23-B676-2738B45ED473</key>
<real>1</real>
</dict>
<key>Version</key>
<integer>1</integer>
</dict>
<key>DisplayUUIDMappings</key>
<dict>
<key>3DD7ACF4-ABD4-DA03-0F93-5A69417CA049</key>
<string>F45E08B2-FFFE-4C23-B676-2738B45ED473</string>
</dict>
</dict>
</plist>
Click to expand...
Manually adding the section to the files did the trick. Thank you very much!
 
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Hi

Had the plist hack working with Big Sur - not working with Monterey though. It seems to switch from RGB to YPbPr shortly after boot. I've checked /Library/Preferences and ~/Library/Preferences/ByHost. Anyone have a suggestion please?

<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>
</dict>
 
mzxgame said:
Hi

Had the plist hack working with Big Sur - not working with Monterey though. It seems to switch from RGB to YPbPr shortly after boot. I've checked /Library/Preferences and ~/Library/Preferences/ByHost. Anyone have a suggestion please?

<key>LinkDescription</key>
<dict>
<key>BitDepth</key>
<integer>8</integer>
<key>EOTF</key>
<integer>0</integer>
<key>PixelEncoding</key>
<integer>0</integer>
<key>Range</key>
<integer>1</integer>
</dict>
Click to expand...
Based on your description it sounds just like ByHost location set it to YPbPr because that is used specific setting and happens after you login.

You are really sure it is that in both locations and there is not several displays listed in your plist file? If there are more than one, you should check you edited it for the right display, or do it for all of them. If you have only one display and your plist sees several, it could be easier to delete them and recreate again to start fresh and then editing LinkDescription there. Just few post back I described how to do that. AGAIN MAKE SURE YOU BACKUP YOUR SYSTEM BEFORE DOING THAT AND DO IT AT YOUR OWN RISK!
 
0906742 said:
Based on your description it sounds just like ByHost location set it to YPbPr because that is used specific setting and happens after you login.

You are really sure it is that in both locations and there is not several displays listed in your plist file? If there are more than one, you should check you edited it for the right display, or do it for all of them. If you have only one display and your plist sees several, it could be easier to delete them and recreate again to start fresh and then editing LinkDescription there. Just few post back I described how to do that. AGAIN MAKE SURE YOU BACKUP YOUR SYSTEM BEFORE DOING THAT AND DO IT AT YOUR OWN RISK!
Click to expand...

I keep all files on NAS and backed up to cloud & external HDD. I think good advice if you are messing with your system.

I think the issue was multiple entries for each display. I was seeing the screen 'darken' before I logged in, just a second after the login screen appears.

I deleted and recreated com.apple.windowserver.displays.plist again and added in LinkDescription manually and everything works.
 
mzxgame said:
I think the issue was multiple entries for each display. I was seeing the screen 'darken' before I logged in, just a second after the login screen appears.

I deleted and recreated com.apple.windowserver.displays.plist again and added in LinkDescription manually and everything works.
Click to expand...
Thanks for confirming it worked for you too. I'm pretty sure plist trick should work for all monitors and those who seem still having problem with this even editing plist are "doing it wrong". :)
I think these past few posts should give information how to do it correctly.
 
Anyone tried BetterDummy out with a 2K monitor?

github.com

GitHub - waydabber/BetterDisplay: Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more!

Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more! - waydabber/BetterDisplay
github.com github.com

M1 macs tend to have issues with custom resolutions. Notoriously they don't allow sub-4K resolution displays to have HiDPI ("Retina") resolutions even though (for example) a 24" QHD 1440p display would greatly benefit from having an 1920x1080 HiDPI "Retina" mode.
 
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for anyone using a monitor with usb-c hub, try this:
in the Display setting, change USB C Prioritization from High data speed to High Resolution.
The Input color format will automatically change to RGB
Other monitors could have something similar. Goodluck!
My monitor is dell s2722qc, used with macbook air m1 MacOS 12.0.1.
p/s
With my other dell s2722dc, it doesn't have the setting mentioned above, and changing the plist file did't work. Using the other trick (change to RGB color on HDMI connection then quickly swap to ubc c cable) worked when I was on macos 11. And it stayed on RGB after i updated to macos 12.
 

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Hi everyone! On the brink of getting an M1 mini but I have a set of Iiyama 1080p monitors (24" and 22").
Is it a lost cause running the m1 on these or did Monterey at least make it usable? My displays only support (HDMI, DVI and VGA) No DP unfortunately.
 
jeroenr92 said:
Hi everyone! On the brink of getting an M1 mini but I have a set of Iiyama 1080p monitors (24" and 22").
Is it a lost cause running the m1 on these or did Monterey at least make it usable? My displays only support (HDMI, DVI and VGA) No DP unfortunately.
Click to expand...
1080p will look like trash, unfortunately. Even 1440p looks like trash. As soon as you hit 4K, you can start to take advantage of HiDPI/pixel doubling resolution.
 
Aggedor said:
1080p will look like trash, unfortunately. Even 1440p looks like trash. As soon as you hit 4K, you can start to take advantage of HiDPI/pixel doubling resolution.
Click to expand...
Okay, so no point in getting the mini without getting a 4K display simultaneously then? Was hoping the text would at least be close to how Windows/Linux handle it.
 
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jeroenr92 said:
Okay, so no point in getting the mini without getting a 4K display simultaneously then? Was hoping the text would at least be close to how Windows/Linux handle it.
Click to expand...
Corrrect, no point for even consider getting under 4K monitor if you are shopping for one. Using tricks to get HiDPI working in 1080p or 1440p monitor gives hardly marginal improvement, especially if you want to get as much desktop screen estate as possible.
 
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