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

amitdel · Dec 21, 2020

Krevnik said:
More accurately, YPbPr 422 bad. YPbPr 444 doesn't suffer from the lack of chroma detail that 422 does. That said, it does seem like everyone having issues is somehow getting kicked into 422 mode for some reason. That seems like a bad bug.

But yes, RGB is ideal.

Thanks for this extremely useful information! Reading up on these modes helps me make more sense of what's going on. As an example, I saw better colors with my P series monitor compared to the U, even though both were outputting YPbPr, and the P monitor was significantly cheaper. Not as good as RGB though, atleast for me!

The description of chroma compression and subsampling on various sites aligns perfectly with my experiences!

Would you know any way to determine if one is seeing YPbPr 444 or YPbPr 422? (Either in some system menu, or on the OSD)? It would help hone in on an acceptable display without subjectivity.

amitdel · Dec 21, 2020

n0dragon said:
I have a Mac mini M1 and Dell U2720Q, and I am now able to get the RGB mode working. You need a spare Intel Mac. Here is what I did.

1. Connect the monitor with the Intel Mac.
2. Use the script https://gist.github.com/adaugherity/7435890 to generate the EDID patch on the Intel Mac. Since the script only works on Intel Macs and not M1 ones, you can only generate the file on the Intel Mac.
3. Disconnect the monitor from the Intel Mac and connect it to the M1 Mac.
4. Transfer the whole folder to the M1 Mac, and place it into /Library/Displays/Contents/Resources/Overrides directory. Create the directory if it does not exist before.
5. Go to display settings on the M1 Mac, and turn OFF HDR (this is the most important step. Turning on HDR will always output YPbPr to the Dell monitor).
6. In the Dell monitor, set colour preset mode to Standard, and set Smart HDR to DisplayHDR (if set to Disable, sometimes it won't work).
7. Restart the M1 Mac.

After restart, my monitor is showing RGB as the colour mode. Now is the most interesting part. I had to delete that override folder, otherwise the next restart my Mac mini will revert back to use YPbPr again.

8. Delete the override folder inside /Library/Displays/Contents/Resources/Overrides directory, and restart the M1 Mac again.

View attachment 1699087

This is amazing! Glad to know some kind of fix exists - thanks for figuring this out, and for taking the pains to share in such great detail.

I don't have an Intel Mac handy (Just starting out with Macs), but perhaps may be extremely useful for @aednichols and @Sarpanch ? Will try and arrange something at my end as well

viss · Dec 21, 2020

Nice n0dragon ! Does your U2720Q look better when in RGB mode & this fix ?

Mistercharlie · Dec 21, 2020

Does anyone have the Dell U3219Q, and would you be willing to generate this script and share it here?
The only Intel Mac I have is an old 2010 iMac, so I don't have cables to connect it to the new Dell.

n0dragon · Dec 22, 2020

viss said:
Nice n0dragon ! Does your U2720Q look better when in RGB mode & this fix ?

The previous setup with HDR looks ok to me. I haven't experienced the font fuzziness and strange colours that others have mentioned (but video in HDR does appear a bit odd in colors). This RGB setup also looks good to me. I have set the colour profile to Display P3 in macOS settings. Things look more like the screen on MBP, except for the lack of HDR support.

amitdel · Dec 22, 2020

I chanced upon something interesting with my M1 MacBook Air and the Dell U2415.

When I connected via a HDMI cable, with the laptop on battery; as soon as I fully closed the lid (triggering clamshell mode), I got a brilliant and beautiful display on the monitor (I was on a webpage with white background, and the quality of the white changed immediately on lid close).

This display persisted for about 2 seconds, and then the monitor started showing "searching for a signal"

This is apparently expected behaviour, because the laptop needs to be on mains when used in clamshell mode.

Now in the above state, when I attached the power, the display came on, but in the weird purple, green hues. The Dell OSD showed RGB as the selected state! Switching to YPbPr brought up the regular display once again.

I am unable to reproduce this reliably each time, but obviously Mac+monitor is capable of a) Defaulting to RGB (in that 2 second window) and b) Displaying the proper colours!

The issue is how to do this reliably and permanently!

Btw, disbling font smoothing, and putting sharpness to 100% helps a lot with the text in my case. Light colored text on black background is ok. Black text on white is problematic, on my setup.

To see the issue with colours for those using with YPbPr - focus on a) The red of the UI close button b) The green of the excel icon and c) The blue of the word icon. You may see washed out colors the way I am seeing.

Apparently, RGB signal send Red, Green and Blue information per pixel, while YPbPr send chrominance and luminance data per pixel (not sure, but from what I gather).

Cheers

jelu77 · Dec 22, 2020

n0dragon said:
I have a Mac mini M1 and Dell U2720Q, and I am now able to get the RGB mode working. You need a spare Intel Mac. Here is what I did.

1. Connect the monitor with the Intel Mac.
2. Use the script https://gist.github.com/adaugherity/7435890 to generate the EDID patch on the Intel Mac. Since the script only works on Intel Macs and not M1 ones, you can only generate the file on the Intel Mac.
3. Disconnect the monitor from the Intel Mac and connect it to the M1 Mac.
4. Transfer the whole folder to the M1 Mac, and place it into /Library/Displays/Contents/Resources/Overrides directory. Create the directory if it does not exist before.
5. Go to display settings on the M1 Mac, and turn OFF HDR (this is the most important step. Turning on HDR will always output YPbPr to the Dell monitor).
6. In the Dell monitor, set colour preset mode to Standard, and set Smart HDR to DisplayHDR (if set to Disable, sometimes it won't work).
7. Restart the M1 Mac.

After restart, my monitor is showing RGB as the colour mode. Now is the most interesting part. I had to delete that override folder, otherwise the next restart my Mac mini will revert back to use YPbPr again.

8. Delete the override folder inside /Library/Displays/Contents/Resources/Overrides directory, and restart the M1 Mac again.

View attachment 1699087

n0dragon, great info thanks! I do not have an Intel Mac, so I cannot generate the EDID patch. However, I thought maybe it was not the script since it didn’t work for other people with M1 Macs. So, I tried to switch on smart HDR -> DisplayHDR in the OSD menu, restarted my mini and lo and behold. It is now in RGB mode. HDR switch must have triggered something making the Mac Mini think it is a monitor and not a TV……..great info for all Dell U2720Q owners….thanks again

Mistercharlie · Dec 22, 2020

jelu77 said:
n0dragon, great info thanks! I do not have an Intel Mac, so I cannot generate the EDID patch. However, I thought maybe it was not the script since it didn’t work for other people with M1 Macs. So, I tried to switch on smart HDR -> DisplayHDR in the OSD menu, restarted my mini and lo and behold. It is now in RGB mode. HDR switch must have triggered something making the Mac Mini think it is a monitor and not a TV……..great info for all Dell U2720Q owners….thanks again

I tried the same with the U3219Q and it didn’t help. I switched on Smart HDR and restarted, and it’s still not using RGB.

jelu77 · Dec 22, 2020

Mistercharlie said:
I tried the same with the U3219Q and it didn’t help. I switched on Smart HDR and restarted, and it’s still not using RGB.

Do you have USB C to USB C connection? I have TB3 to TB3 but it should be the same.

Maybe my M1 is possessed and tomorrow I have YPbPr again, who knows. Something with Macs and Dell monitors is not right. I still think we should have the option to set this ourselves in display settings.

aednichols · Dec 22, 2020

Mistercharlie said:
Does anyone have the Dell U3219Q, and would you be willing to generate this script and share it here?
The only Intel Mac I have is an old 2010 iMac, so I don't have cables to connect it to the new Dell.

I did not end up keeping the monitor (for this and other reasons) but I believe I still have the file. I can check after work.

Mistercharlie · Dec 22, 2020

jelu77 said:
Do you have USB C to USB C connection? I have TB3 to TB3 but it should be the same.

Maybe my M1 is possessed and tomorrow I have YPbPr again, who knows. Something with Macs and Dell monitors is not right. I still think we should have the option to set this ourselves in display settings.

USB-C to USB-C, and also Thunderbolt to DisplayPort via Caldigit dock. I also have a replacement M1 mini arriving soon (this one has display connection problems on boot) so it could be that.

aednichols said:
I did not end up keeping the monitor (for this and other reasons) but I believe I still have the file. I can check after work.

That would be fantastic!

aednichols · Dec 22, 2020

Mistercharlie said:
USB-C to USB-C, and also Thunderbolt to DisplayPort via Caldigit dock. I also have a replacement M1 mini arriving soon (this one has display connection problems on boot) so it could be that.

That would be fantastic!

File path: DisplayVendorID-10ac / DisplayProductID-a125

XML:

<?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>DisplayProductName</key>
  <string>DELL U3219Q - forced RGB mode (EDID override)</string>
  <key>IODisplayEDID</key>
  <data>AP///////wAQrCWhTEszMCQeAQS1Rid4Ju6Vo1RMmSYPUFSlSwBxT4GAqcCp
QNHA4QDRAAEBTdAAoPBwPoAwIDUAuYghAAAaAAAA/wBHMFdLNDEzCiAgICAg
AAAA/ABERUxMIFUzMjE5UQogAAAA/QAxVgqJNgEKICAgICAgANk=
</data>
  <key>DisplayVendorID</key>
  <integer>4268</integer>
  <key>DisplayProductID</key>
  <integer>41253</integer>
</dict>
</plist>

Mistercharlie · Dec 22, 2020

aednichols said:

File path: DisplayVendorID-10ac / DisplayProductID-a125

XML:

<?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>DisplayProductName</key>
  <string>DELL U3219Q - forced RGB mode (EDID override)</string>
  <key>IODisplayEDID</key>
  <data>AP///////wAQrCWhTEszMCQeAQS1Rid4Ju6Vo1RMmSYPUFSlSwBxT4GAqcCp
QNHA4QDRAAEBTdAAoPBwPoAwIDUAuYghAAAaAAAA/wBHMFdLNDEzCiAgICAg
AAAA/ABERUxMIFUzMjE5UQogAAAA/QAxVgqJNgEKICAgICAgANk=
</data>
  <key>DisplayVendorID</key>
  <integer>4268</integer>
  <key>DisplayProductID</key>
  <integer>41253</integer>
</dict>
</plist>

Nice! I’ll try that out tonight. thanks!

Mistercharlie · Dec 22, 2020

aednichols said:

File path: DisplayVendorID-10ac / DisplayProductID-a125

XML:

<?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>DisplayProductName</key>
  <string>DELL U3219Q - forced RGB mode (EDID override)</string>
  <key>IODisplayEDID</key>
  <data>AP///////wAQrCWhTEszMCQeAQS1Rid4Ju6Vo1RMmSYPUFSlSwBxT4GAqcCp
QNHA4QDRAAEBTdAAoPBwPoAwIDUAuYghAAAaAAAA/wBHMFdLNDEzCiAgICAg
AAAA/ABERUxMIFUzMjE5UQogAAAA/QAxVgqJNgEKICAgICAgANk=
</data>
  <key>DisplayVendorID</key>
  <integer>4268</integer>
  <key>DisplayProductID</key>
  <integer>41253</integer>
</dict>
</plist>

Just to be sure, when I create and save the XML file, the file name should be

DisplayProductID-a125.xml

correct?

EDIT: I see that there's no file extension required. Still, it's not working

aednichols · Dec 22, 2020

Mistercharlie said:
Just to be sure, when I create and save the XML file, the file name should be

DisplayProductID-a125.xml

correct?

No, surprisingly there must be no extension for it to work.

So /Library/Displays/Contents/Resources/Overrides/DisplayVendorID-10ac/DisplayProductID-a125

aednichols · Dec 22, 2020

Mistercharlie said:
Just to be sure, when I create and save the XML file, the file name should be

DisplayProductID-a125.xml

correct?

EDIT: I see that there's no file extension required. Still, it's not working

Did you reboot and unplug/replug the display?

Even if RGB isn't fixed, System Preferences should show DELL U3219Q - forced RGB mode (EDID override) in its titlebar

Mistercharlie · Dec 22, 2020

aednichols said:
Did you reboot and unplug/replug the display?

Even if RGB isn't fixed, System Preferences should show DELL U3219Q - forced RGB mode (EDID override) in its titlebar

I rebooted, and plugged and unplugged the display. System preferences shows it as Dell U3219Q, just like before, so I think I must have gone wrong somewhere.

I shall check again...

Sarpanch · Dec 22, 2020

n0dragon said:
I have a Mac mini M1 and Dell U2720Q, and I am now able to get the RGB mode working. You need a spare Intel Mac. Here is what I did.

1. Connect the monitor with the Intel Mac.
2. Use the script https://gist.github.com/adaugherity/7435890 to generate the EDID patch on the Intel Mac. Since the script only works on Intel Macs and not M1 ones, you can only generate the file on the Intel Mac.
3. Disconnect the monitor from the Intel Mac and connect it to the M1 Mac.
4. Transfer the whole folder to the M1 Mac, and place it into /Library/Displays/Contents/Resources/Overrides directory. Create the directory if it does not exist before.
5. Go to display settings on the M1 Mac, and turn OFF HDR (this is the most important step. Turning on HDR will always output YPbPr to the Dell monitor).
6. In the Dell monitor, set colour preset mode to Standard, and set Smart HDR to DisplayHDR (if set to Disable, sometimes it won't work).
7. Restart the M1 Mac.

After restart, my monitor is showing RGB as the colour mode. Now is the most interesting part. I had to delete that override folder, otherwise the next restart my Mac mini will revert back to use YPbPr again.

8. Delete the override folder inside /Library/Displays/Contents/Resources/Overrides directory, and restart the M1 Mac again.

View attachment 1699087

Thanks for sharing! Unfortunately, this method didn’t work for Dell U2518D. Tried all options, but the output is still YPbPr.

Sarpanch · Dec 22, 2020

Mistercharlie said:
I rebooted, and plugged and unplugged the display. System preferences shows it as Dell U3219Q, just like before, so I think I must have gone wrong somewhere.

I shall check again...

If I enable Smart HDR on my monitor settings, then macOS does not pick the override file (shows Display as DELL U2518D). If I disable Smart HDR, it automatically picks up the Override file, but still defaults to YPbPr.

aednichols · Dec 22, 2020

Sarpanch said:
If I enable Smart HDR on my monitor settings, then macOS does not pick the override file (shows Display as DELL U2518D). If I disable Smart HDR, it automatically picks up the Override file, but still defaults to YPbPr.

In my testing on U3219Q I had HDR disabled the whole time (not appropriate for my workflow) and never got RGB.

n0dragon · Dec 22, 2020

jelu77 said:
n0dragon, great info thanks! I do not have an Intel Mac, so I cannot generate the EDID patch. However, I thought maybe it was not the script since it didn’t work for other people with M1 Macs. So, I tried to switch on smart HDR -> DisplayHDR in the OSD menu, restarted my mini and lo and behold. It is now in RGB mode. HDR switch must have triggered something making the Mac Mini think it is a monitor and not a TV……..great info for all Dell U2720Q owners….thanks again

Yes, the patch file might never work like before, because I never saw the patched display name in the settings. It was always Dell U2720Q in the display settings. However, when I restarted after putting the patch file in place, the display resolution changed, and the HDR setting was automatically disabled. I think the system might try to detect or recognise the monitor again.

With or without the patch file, I think the more important thing is to set SmartHDR to DisplayHDR, but set HDR setting in macOS to disabled, and restart macOS. If I enable and disable HDR in settings, the color will still be YPbPr. Only when I restarted the Mac did it change back to RGB.

jelu77 · Dec 22, 2020

Right, my M1 Mini was back to YPbPr when display came back from sleep this morning (never turn off or sleep the M1 Mini) and also resolution reset. Scaled back the resolution, restarted and RGB again, very strange

Mistercharlie · Dec 23, 2020

Mistercharlie said:
I rebooted, and plugged and unplugged the display. System preferences shows it as Dell U3219Q, just like before, so I think I must have gone wrong somewhere.

I shall check again...

I managed to hook the monitor up to an Intel Mac, and it was simple enough to generate the script. I dropped that into the /Library/Displays/Contents/Resources/Overrides/ folder, and now System Prefs shows the display as DELL U3219Q - Forced RGB Mode, but it doesn't actually connect in RGB mode.

amitdel · Dec 23, 2020

erroneous update. please ignore

Ninja Dom · Dec 23, 2020

I wonder if this fix coming below will also fix our issue.

Apple to Fix Resolution Issue With Ultrawide Displays on M1 Macs in Future macOS Update

In a new support document, Apple has acknowledged that when an ultrawide or super-ultrawide external display is connected to a Mac with the M1 chip,...

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