Force RGB Color on M1 Mac

Force-RGB-Color-on-M1-Mac.md

Force RGB Color on M1 Mac

How to Force RGB Color Output instead of YPbPr on your M1 Apple Silicon Mac for an External Monitor.

This step-by-step video tutorial will guide you through the procedure of forcing RGB color output on your M1 Mac.

Here is the direct link to the video tutorial: https://www.youtube.com/watch?v=Z1EqH3fd0V4

The video also has Closed Captions (Subtitles) that you can enable, to make it easier to follow if needed.

Please note that you're doing any changes on your own risk.

Terminal commands used in the video

Here are each of the Terminal commands mentioned in the tutorial, so that you can just copy and paste them:

open /Library/Preferences

plutil -convert xml1

plutil -convert binary1

plutil -lint

The step-by-step procedure on how to force RGB Color Output on M1 and M2 based Macs with Terminal commands

1. Open Terminal and use this command to make Finder select the displays plist file:
   open -R /Library/Preferences/com.apple.windowserver.displays.plist

2. Drag and drop the com.apple.windowserver.displays.plist file to Desktop manually. Don't use the cp command, as it won't add your current user with writing privileges.

3. Convert the file to XML:
   plutil -convert xml1 ~/Desktop/com.apple.windowserver.displays.plist

4. Open the converted file with the default plain text editor (avoid using the built-in TextEdit app if possible, since it might modify the file and make it unreadable by the system)
   open -t ~/Desktop/com.apple.windowserver.displays.plist
   or
   open -a CotEditor.app ~/Desktop/com.apple.windowserver.displays.plist

5. Copy and paste the missing LinkDesription Key under the current display (check the screenshot below for an example of how it should look like):
   

				<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>

6. Save the file and then convert it to binary again:
   plutil -convert binary1 ~/Desktop/com.apple.windowserver.displays.plist

7. Check if the plist file is valid:
   plutil -lint ~/Desktop/com.apple.windowserver.displays.plist

8. Open the /Library/Preferences/ folder again:
   open /Library/Preferences/

9. Drag and drop the updated com.apple.windowserver.displays.plist file from Desktop to the Library folder manually. Don't use the cp command, as it won't add your current user with writing privileges.

10. Right Click on the com.apple.windowserver.displays.plist file in the Library folder and click on Get Info

11. Check the boxes for Stationery and Locked.

12. Reboot the Mac.

That's it!

(Alternative) Terminal commands to force RGB Color Output on M1 and M2 based Macs and workaround for losing RGB color after waking up from sleep

1. Open Terminal

2. Paste the following commands to edit the User's displays plist file com.apple.windowserver.displays.[UUID].plist using the built-in PlistBuddy function in macOS:

/usr/libexec/PlistBuddy -c "add DisplaySets:Configs:DisplayConfig:DisplayConfig:DisplayConfig:LinkDescription:BitDepth integer" ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist
/usr/libexec/PlistBuddy -c "set DisplaySets:Configs:DisplayConfig:DisplayConfig:DisplayConfig:LinkDescription:BitDepth 8" ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist
/usr/libexec/PlistBuddy -c "add DisplaySets:Configs:DisplayConfig:DisplayConfig:DisplayConfig:LinkDescription:EOTF integer" ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist
/usr/libexec/PlistBuddy -c "add DisplaySets:Configs:DisplayConfig:DisplayConfig:DisplayConfig:LinkDescription:PixelEncoding integer" ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist
/usr/libexec/PlistBuddy -c "add DisplaySets:Configs:DisplayConfig:DisplayConfig:DisplayConfig:LinkDescription:Range integer" ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist

3. Reboot your Mac
   
   

(Workaround) If your Mac loses RGB color after waking up from sleep mode, either Reboot your Mac (recommended) or use this Terminal command to stop the WindowServer and login again (not recommended):

sudo killall -HUP WindowServer

End result

The end result is having your M1 mac output RGB color to your external monitor instead of YPbPr, potentially making the colors more accurate and the text a bit more crisp, even on older 1080p monitors.

Hopefully this tutorial would be useful to someone.

Please feel free to ask in the comment section if you have any questions regarding this procedure.

Background

While doing a lot of testing on how the Dual-Cable workaround makes RGB to work on M1, I've discovered what changes it makes to macOS, and managed to create a more streamlined workaround without the need to use a second cable.

To make things easier, I've created a step-by-step video tutorial of the whole procedure that should force RGB color output on your M1 Mac connected to an external monitor, and works on an HDMI-to-HDMI cable connection.

Credits

Big thanks goes to the amazing community and all their help over the years to solve issues like this:
https://gist.github.com/ejdyksen/8302862
https://gist.github.com/adaugherity/7435890

Useful Sources

Apple Open Source Project Files for Displays and Graphics
https://opensource.apple.com/source/IOKitUser/IOKitUser-1445.60.1/graphics.subproj/IODisplayLib.c
https://opensource.apple.com/source/IOGraphics/IOGraphics-517.17/IOGraphicsFamily/IOFramebuffer.cpp.auto.html

How to Edit and Convert binary plist files
http://hints.macworld.com/article.php?story=20050803111126899
https://apple.stackexchange.com/questions/155393/how-to-beautify-binary-dict-files
https://discussions.apple.com/thread/1768480

How to Edit plist files using defaults and PlistBuddy
https://ss64.com/osx/defaults.html
https://github.com/mathiasbynens/dotfiles/blob/master/.macos

Apps based on this method

@sudowork has created an awesome script written in Phyton that automates the steps and checks for duplicate files.
You can find more info about it here: https://github.com/sudowork/fix_m1_rgb

@dangh has created an alernative script for fishshell.
You can find more info about it here: https://github.com/dangh/force-rgb.fish

@GetVladimir I've also created a Shortcut to Force RGB Color Output using the built-in Shortcuts app.
You can find how to create the Shortcut here: https://gist.github.com/GetVladimir/c89a26df1806001543bef4c8d90cc2f8?permalink_comment_id=4531552#gistcomment-4531552

@entropyconquers has created a script based on this method written in Phyton that automates the steps, makes a backup and checks for duplicate files.
You can find more info about it here: https://github.com/entropyconquers/Force-RGB-Color-on-M1-M2-Mac-Script

Additional notes

Multiple PixelEncoding and Range keys in the same plist file
Note that there might be multiple instances of the PixelEncoding and Range keys in the same file, one for each output of your monitor and for different AirPlay devices. You might need to update the integer on each one to get RGB color output on all displays.

Getting RGB color only before login
There might be multiple duplicate plist files with the same name in different locations.

Make sure that you only have the main modified file in:
/Library/Preferences

Then make a backup and remove duplicate displays plist files from these locations (if any):
~/Library/Preferences
or
/Users/username/Library/Preferences
and
/Users/username/Library/Preferences/ByHost

Please note that you'll need to have administrator privileges in order to modify the file in /Library/Preferences. Thanks goes to @keegandent and @StrategicalIT for pointing this out.

Updates regarding macOS Monterey

USB-C to DisplayPort
From what I've seen, it seems that macOS Monterey 12.0.1 finally outputs RGB color by default on some monitors when using USB-C to DisplayPort cable on M1 Apple Silicone Macs.

You might need to make a backup and delete these 2 files:
/Library/Preferences/com.apple.windowserver.displays.plist
and
/Users/yourname/Library/Preferences/ByHost/com.apple.windowserver.displays.[UDID].plist

Restart your Mac and it should properly output RGB color on the monitor on the next boot.

HDMI to HDMI
The situation with HDMI seems to got a bit more complicated. Now the whole section for the LinkDescription might be missing from the com.apple.windowserver.displays.plist on a clean install and doesn't seem to be recreated when rotating the screen either.

Luckily, the solution still works, but you might need to manually add this whole section in the displays plist file:

					<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>

The section usually goes right under the CurrentInfo key, and it should look something like this:

This should get your RGB color output working on M1 Mac mini, even when connected with HDMI to HDMI cable.

Multiple monitors when one them is using HDMI to HDMI
Additional thanks goes to @somogyi-ede who tested this with multiple monitors and confirmed that the LinkDescription key needs to be added under each monitor instance in order for all of them to receive RGB color output. Link to the comment

Updates regarding macOS 13 Ventura

USB-C to DisplayPort
The macOS 13 Ventura beta seems to outputs RGB color by default on some monitors when using USB-C to DisplayPort cable on M1 Apple Silicone Macs.

You might need to make a backup and delete these 2 files:
/Library/Preferences/com.apple.windowserver.displays.plist
and
/Users/yourname/Library/Preferences/ByHost/com.apple.windowserver.displays.[UDID].plist

Restart your Mac and it should properly output RGB color on the monitor on the next boot.

HDMI to HDMI
Similar as macOS Monterey, the situation with HDMI on macOS Venturs seems a bit more complicated. Usually the whole section for the LinkDescription might be missing from the com.apple.windowserver.displays.plist on a clean install and doesn't seem to be recreated when rotating the screen either.

Luckily, the solution still works, and you still need to manually add this whole section in the displays plist file:

					<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>

The section usually goes right under the CurrentInfo key, and it should look something like this:

This should get your RGB color output working on M1 Mac mini, even when connected with HDMI to HDMI cable.

(Optional) Lock the plist file and set it as stationary
After the macOS Ventura 13.3 update, the plist file seems to get overwritten on reboot.

After you make the edits in the file, you can try setting the file /Library/Preferences/com.apple.windowserver.displays.plist as Stationery pad and Locked, so that it doesn't get overwritten on every reboot

To do this, right click on the plist file, click on Get Info and check the boxes next to Stationery pad and Locked

This requires further testing and might cause some issues, like not being able to remember new resolutions or display settings. Please note that you're making any changes at your own risk.

Updates regarding macOS 14 Sonoma Beta

USB-C to DisplayPort
The macOS 14 Sonoma seems to outputs RGB color by default when using USB-C to DisplayPort cable.

HDMI to HDMI
The macOS 14 Sonoma seems to outputs YCbCr color by default when using HDMI to HDMI cable.

• Forcing RGB Color Output still seems to work with the original procedure of modifying the plist files

• Modifying the display plist files still works with the alternative version

• After the plist files are modified, putting the Mac to sleep and waking it, it seem to keep the RGB Color output (this seems to be fixed at least on a M1 Mac mini)

If you have any additional questions, please feel free to contact me.

@taylor325 @GetVladimir do you think this could be done without BetterDisplay? I would like to try first but my trial already expired a few months ago. I would like to keep using my USB-C Hub for display output instead of the adapter.

EDIT: Seems like it's working fine after applying this workaround. RGB with 120Hz. Even with HDMI through the same dock :)

Hello @LetrixZ Maybe they will fix the bug in macOS Sonoma. BetterDisplay is first aid for me for every day life with M1 Mac.

Automating RGB Color Force on M1/M2 Macs

Hello @LetrixZ @taylor325 @Averyy @Anatharias @traderdude123 @marekdvorak81

I have created a script that automates the steps mentioned by @GetVladimir to force RGB color mode on external monitors for M1/M2 Macs. I have tested it on a Mac Air with M1 chip.

You can find the script and its instructions in the following repository: Force-RGB-Color-on-M1-M2-Mac-Script

Feel free to try it out and update this README if it works for you as well. Cheers!

@entropyconquers awesome work, thank you so much for creating the script and for sharing it!

I will check it out and update the post as soon as I'm in front of a computer.

Update: I've added a link to the script in the original post: https://gist.github.com/GetVladimir/c89a26df1806001543bef4c8d90cc2f8#apps-based-on-this-method

@entropyconquers

you could write the entire script in python. why write half in bash? any particular reason?

In any case , good effort. Appreciate it.

Thanks a ton @GetVladimir and @entropyconquers for your efforts. struggled a long time with my M1 you made my day 🎊 🚀

@entropyconquers

you could write the entire script in python. why write half in bash? any particular reason?

In any case , good effort. Appreciate it.

@traderdude123 for some reason running python with sudo was not enough to copy and move/rename the plist file from /Library/Preferences.

I tried writing the whole thing with bash but modifying JSON/XML is a nightmare in bash without any external dependency.

@mafeko thank you so much for your comment and I'm glad to hear that you got RGB color output working

@entropyconquers
can you try this.

Write entire thing in python
then

1. chmod +x pythonscript.py
2. sudo -E pythonscript.py

Thanks @taylor325 @GetVladimir ! It's been years and I can finally calibrate my monitors with some reasonable confidence.

@carlosvigil Awesome! Thank you so much for your comment and I'm glad to hear that you got RGB color output working

For some reason these methods only work if I keep my MacBook Air M1 opened. If I close the lid or connect my Monitor with the lid closed it uses YPbPr. I would prefer to run my Macbook in Clamshell mode but I can't.
The only way to get RGB working with a closed lid is right after a reboot. But then the USB Hub in my Monitor (Dell P3421W) won't work.

@Kimbo0o yes, you're right. The more recent versions of macOS Ventura reset the RGB color when waking the MacBook from sleep.

One workaround is to reboot it or prevent it from going to sleep.

I'm not sure how that will work with your USB hub though. It might be better to connect your monitor directly to the MacBook in that case

@marekdvorak81 and @GetVladimir

As a paid alternative , might I suggest Better Display. with Better Display , you don't need to reboot after going to sleep. It retains the RGB Settings without even a screen refresh.

Please note I m not in any way affiliated with Better Display. This recommendation is purely based on my experience as a paid users of Better Display.

As of now this is the only working solution that meets the users requirements. The rebooting just to keep the RGB settings is a real pain in practice. That's why I bought BD.

Don't get me wrong @GetVladimir , but this plist modification method is a hit or a miss. but BD Utility is a sure way.

Thank you for all your suggestions. The color issue with the external monitor can be quite frustrating, and I'm interested in trying the troubleshooting methods you provided. However, I have some questions now. Can I get help from you regarding the implementation of using the BD to modify EDID and upload it? Is this implementation done at the software level or does it directly modify the firmware of the display? If it modifies the firmware of the display, will it lead to any missing features when other devices are connected to this display? I would greatly appreciate it if you could find some time to answer my questions!

@asipirn

Modifying and uploading of EDID is done at a software level. There is no modification of firmware of the display.

To modify the firmware of the display , only the manufacturer of the display can provide the utility to do so. not a 3rd party utility like BD.

BD allows you to reset the EDID to original at any time. you can check the BD GitHub page for more details.

@GetVladimir Any advice on how to do the almost opposite, I want to force YCBCR444 (for whatever reason looks far better on my projector). Any idea what the values should be for this?

@JamieRosenberg thank you for your question. Yes, the Pixel Encoding should be set to 1 and this would usually give you YCbCr color output.

Not sure whether it will be 4:4:4 though.

I updated my work Mac to Ventura 13.4.1 last Friday, and today I plugged it on my monitor via HDMI and suddenly the colors were fixed!
Not sure if they changed something, or if it's just temporary luck on my side. Anyone else had a similar experience?

@vittau thank you for the comment.

That is awesome! I haven't heard more reports about it, but it would be great if they fixed it

Confirmed on my end as well @vittau . 🎊 😍 finally !

@mafeko thank you for the confirmation! That is awesome

I updated my work Mac to Ventura 13.4.1 last Friday, and today I plugged it on my monitor via HDMI and suddenly the colors were fixed! Not sure if they changed something, or if it's just temporary luck on my side. Anyone else had a similar experience?

does it mean it should output RGB on HDMI by default? For me, the output is still YPbPr. MacOS 13.4.1.

It's not consistent apparently, sometimes it's fixed, and sometimes it's not...
EDIT: It appears to break after sleeping, and then fixes itself again after restarting.

It's not consistent apparently, sometimes it's fixed, and sometimes it's not...
EDIT: It appears to break after sleeping, and then fixes itself again after restarting.

It definitely not fixed the problem after sleeping.

I have found that as soon as the screen goes to sleep or I unplug it, the fix no longer works. A reboot solves the problem but only as long as you keep the screen awake. Any solution for this?

@esmorun

Paid - Yes.
Free - No.

Best bet would be Sonoma. But its still in beta so not recommended.

@traderdude123 does Sonoma beta fix the problem or just a guess?

@traderdude123 Has it been confirmed fixed in Sonoma? The bug has been around for as long as I have had my M1 air so I wouldn't count on Apple ever fixing the bug.

By the way you should all make sure to send a report to Apple: https://www.apple.com/feedback

@jacek-jablonski
@esmorun

I have not tested on Sonoma. waiting for public release.

But i have read reports from other users who are using beta. They are even getting 4k 120hz RGB 10 bit with AMD 6000 Series cards on hackintosh's as well. This was not possible on Ventura. So its high likely that the sleep issue could be fixed on Sonoma.

if anyone is brave enough to test it on beta. It would be great. If anyone does test it. please let us know.

I've just tested it on Sonoma Developer Beta 3. I've deleted all the display plist preferences files and started fresh.

Here are the results:

• The HDMI to HDMI connection still defaults to YCbCr Color Output (as usual)
• The USB-C to DisplayPort connection defaults to RGB Color Output (as usual)
• Forcing RGB Color output still seems to work with the original procedure of modifying the plist files
• Modifying the display plist files still works with the alternative version
• After the plist files are modified, putting the Mac to sleep and waking it, it seem to keep the RGB Color output (so this one seems to be fixed, at least on a M1 Mac mini)
• There was a strange issue with the Magic Mouse connecting and disconnecting every few seconds after restarting Sonoma a few times. Turning off the Magic Mouse and turning it on seems to fix this for the moment.

@GetVladimir

Thanks for the confirmations. Finally, some progress.

Also the HDMI-HDMI defaulting to YCBCR is actually correct since HDMI is predominantly used by TVs and YCBCR gives the best picture quality. However if you want to use it as a Monitor we need RGB. But normally its not expected that people use TV as monitors.

For monitors , USB-C/DP is primary connection and hence defaults to RGB , which is also the correct thing to do.

But what apple needs to provide is a user selectable option in the Display section of settings for YCBCR or RGB.