Disable EDR for non-XDR Apple displays?

[Vvorcun]

Is it possible to disable EDR on non-HDR displays (Apple Studio Display, MacBook Air M1 2020, etc)?

[waydabber]

You should have a toggle for this in System Settings. Should look like this:

Note: of course you'll need to do the OPTION trick for this setting to appear:

• Close System Settings
• Hold and keep holding the OPTION key
• Open System Settings while still keep holding OPTION key
• Then click on Displays while still keep holding OPTION key

[Vvorcun]

Sadly this doesn't work on MacBook Air M1 (latest macOS Sonoma 14.4) - even with OPTION trick this toggle doesn't appear. Maybe it's possible to force disable this via MonitorPanel.framework or SkyLight.framework?

[waydabber]

Hmm. I tried it on Sonoma 14.4 but the Intel MBP. I don't have non-XDR Apple Silicon Mac with me now so I can't try it. :( Did you press the OPTION all the way? It is not enough to simply press OPTION while opening Displays, you need to opten System Settings that way from a closed state and press OPTION all the way until you open Displays.

I don't use MonitorPanel.framework anymore as it is super-slow but the feature should be available using SkyLight (most MonitorPanel stuff eventually calls something in SkyLight).

[waydabber]

But I see from "Rotation" appearing that you did the right way and the EDR option does not appear. So I guess the technique this does not work for Apple Silicon Macs indeed. :(

[Vvorcun]

Yeah, I tried both with OPTION and without it - it only makes "Rotation" appear for me. Would be awesome if disabling EDR on Apple Silicon Macs would be possible with BetterDisplay at some point - I've tried to fiddle with SkyLight.framework myself, but sadly I wasn't able to figure it out yet

[PuzzledUser]

So I've been trying to use some of the unused available native brightness on my Apple Studio Display to fake HDR. However, this thread seems to be the closest I've found on the topic. I too don't see an option to trick my Mac into treating the ASD as HDR (option is System Settings doesn't help). There is talk of using the XDR upscaling in BD to do this, but I can't fathom it.

There's also talk of faking EDID to make my Mac mini think the ASD is HDR compatible, that sounds fun (and risky).

I tortured Perplexity of the topic to no avail (no real surprise there eh?).

Any suggestions of where to explore on this please?

[waydabber]

Hmm. I thought if you simply lower the brightness to around 50% or so, ASD should (I think) switch to EDR mode to make HDR content appear brighter, just like Apple internal displays do. Isn't this the case? Of course the result will be rather weak as the contrast and dynamic range does not properly support rendering HDR content in meaningful ways I think. You can check whether the display is in EDR mode using BetterDisplay (under Display Information...).

[PuzzledUser]

I am out of my depth here on the terminology. The display doesn't render any HDR bright content (like my iPhone does). Stuff above 100% RBG brightness on a webpage (using say color(rec2020 1.2 1.2 1.2)), appears just at 100% like other whites. Here is what Display Information says regarding potential EDR:

EDIT Oh, screen is at 25% brightness currently/typically

[waydabber]

Yeah. Potential EDR means that the display can show some simulated extra HDR brightness beyond peak SDR brightness when brightness is set to sufficiently low - by generally increasing display backlight and decreasing normal SDR white to some level of gray. This obviously looks horrible for darker content or in a dark room. I don't think simple Safari webpages trigger this though (if Safari would report HDR capability, YouTube and other websites would try to play HDR content which would be confusing and probably end up looking worse than the SDR variant). But as I say, the ASD is not really capable (or designed) for HDR content so I don't think pursuing this makes much sense. :)

[PuzzledUser]

It is quite easy to trigger it in Safari with css of color: color(rec2020 2 2 2); which triggers a whiter than white on iPhone. There seem to me people doing this, but Apple Silicon System Settings (via Option) doesn't seem to allow setting the EDR mode of ASD. BD gets lots of mentions of doing this in association with XDR upscaling, but if you say it doesn't work, then I say, you should know! 🤣

It's a shame, as there is so much unused brightness available and some of the EDR descriptions make it sound tempting, if only for a slight boost depending on screen brightness and ambient lighting. At least then I could preview some of my web work on my ASD rather than reaching for my iPhone.

Cheers!

[waydabber]

There is unused brightness when the brightness is set to lower than 100%, but that should be intentional. :) In this case when EDR is being used, the brightness is boosted and normal content is artificially dimmed. But due to the LCD technology's limitation, blacks become more like gray when this happens, lighting up a dark room for example. So honestly except for some specific circumstances EDR is not very useful and trying to force it makes no sense imho - if one needs brightness, simply increase the brightness. :)

Intel Macs had an option to disable EDR, but no Macs ever had the option to switch-force EDR (you can do it by placing some HDR content on screen). BetterDisplay could switch to EDR mode (it does that for other displays), I just don't do it for non-XDR Apple displays as there seems to be no legitimate point doing so. Since at 100% brightness there is no headroom left, it is not useful for brightness upscaling purposes.

[PuzzledUser]

I appreciate your messages and do understand the risks of blowing out the blacks. Yet to my understanding your software brightness control does just what you describe 😉

In my setup, even with HDR content on-screen, there is no hint of extra brightness in the HDR whites (as the Mac knows I have an SDR ASD). As I'd like to develop my HDR website on my ASD (rather than via iPhone), is there a way to ask/trick BD into telling the Mac that EDR is available on ASD? (The Video Control Settings don't seem to give me that feature. I'm also scared of the Treat as generic third-party (non-Apple) display given its warning about permanent damage).

[waydabber]

I think there is a misunderstanding. EDR is (or should be) available on the ASD. When there is HDR content on screen that macOS thinks should be rendered as such and trigger a switch to EDR mode, it should happen (there is a ramp-up/down period though). If it helps, I could add a feature to show explicitly whether the display is currently in EDR/HDR/XDR mode.

[PuzzledUser]

That would be interesting and helpful as I see no sign of it currently (but perhaps the ramp up period you mention is longer than I've waited). I have many HDR photos and I've never noticed Photos rendering sky over the usual 100% white, like I do on iPhone.

[PuzzledUser]

Did this get into 3.1.1? I don't see it and still would love to explore or fake EDR.

[waydabber]

Sorry, no.

[PuzzledUser]

Just to confirm that EDR is active on my Apple Studio Display (ASD) now I've upgraded to Mac OS 15.0.1 (I never tried 15.0). It works rather well, including on websites and in Photos.

(There are some amusing artefacts in Safari if you push a window to the background and move the shadow of another window across the HDR parts of an image, as the OS redraws the >100% brightness items. Safari HDR text doesn't have this rendering bug/limitation. Photos behaves entirely smoothly when provoking it, with no artefacts I've seen).

As you would expect, from about 60% display brightness, the OS calms down the amount of HDR boost. Surprisingly, there is still a little brightness boost available at full display brightness. Unsurprisingly, Digital Color Meter is oblivious to these shenanigans.

BD Info still shows Potential EDR 2.000000 and Reference EDR 1.000000 for ASD as it did in 14.7. So happy days for me and I look forward to your extra info in BD at some point.

[waydabber]

Nice. So the lack of EDR was then a bug with 14.7?

[PuzzledUser]

Yes, perhaps. But nice to have now.

[PuzzledUser]

Just for future travellers, I noticed that EDR wasn't working in Safari. But then I popped into Photos and noticed it was showing HDR videos in EDR. So, back to Safari and it was rendering content in EDR. Then I quit Photos and EDR in Safari worked for a 10-20 seconds; then stopped working.

Just retesting: I opened Photos and EDR came back in Photos and Safari. Then I quit Photos and scrolled a Safari window with HDR content and counted. At 14 (seconds ish), the scrolling stuttered and EDR turned off! Some heavy process ran for 0.5s or so. The same Safari scroll stuttering happens when re-launching Photos, as EDR re-activates.

EDR stops after about 14s when hiding rather than quitting Photos. However, EDR remains active continuously in Safari if I leave a little bit of the Photos window on-screen, even though its HDR video part is off-screen.

So maybe my EDR wasn't activating back in 14.7, not cos of a bug, but because I wasn't priming it for action with an appropriate EDR enabling application.

Now, if only there was a curious developer with a display mangling application that could add a switch to keep EDR active all the time... 😉

[Vvorcun]

Now, if only there was a curious developer with a display mangling application that could add a switch to keep EDR active all the time... 😉

Is there a point in keeping EDR active all the time? Just set brightness to 100% - display won't be brighter when displaying SDR content in EDR mode. On the other hand (as I mentioned before), it would be awesome to completely disable EDR - perhaps by somehow forcing Potential EDR to 1? I tried fiddling around with various symbols (including setPotentialHeadroom), but never succeeded.

[PuzzledUser]

For me, 100% brightness is too uncomfortable. Yes, EDR doesn't alter SDR content at all. For me EDR allows me to see and use HDR content and I've found Apple only turn it on sometimes.

It seems a three-way switch would make us both happy. EDR: Auto, On, Off.

[PuzzledUser]

Just reflecting on this after playing with software display brightness. One concern for allowing EDR on an SDR display is that contrast/black level is reduced. I imagine the colour lookup table hacking for software brightness would have similar issues. If I'm on the right page, then that hints that encouraging the OS to enable (or disable) EDR might be reasonable for the same reason.

I notice that I never see the EDR option in my System Settings>Display as per the initial post. It would be a nice first step to monitor the current EDR mode in BD as previously hinted.

[waydabber]

Yes, I can add some feature for that. You should add it as an issue/request.

[PuzzledUser]

Great, See issue #3644.