Direct Brightness Upscaling in macOS 26.3+ #4983

Yes, indeed. I'll check to see what can be done about it. Let's track this further under #4929.

(fixed in the latest internal pre-release)

Yes , 26.3 Beta 3 . totally broke.

Right. Those who depend heavily on native XDR upscaling should avoid upgrading to 26.3.

I'll remove this feature going forward for 26.3+ installations. The message is clear from Apple, they don't want this anymore. The technique this uses might interfere with some future products (new displays or the OLED MBP maybe? - not sure). I am sure they have good reasons.

#5049

What fix are you talking about?

Sorry, this is probably a misunderstanding. There was a pre-release that fixed the native XDR upscaling in 26.3 beta1 and 2, but then Apple decided to counter that (or make further changes due to unrelated reasons, who knows...). So right now native upscaling is not available, macOS will remove any preset that is out of bounds and this protection cannot is something we have no way of overcoming (in a reasonable way that is suitable for an app geared for normal users).

It would be nice if you provided a SIP off version that would tweak the frameworks needed to be tweaked so it could work again, for more advanced users who want to do the extra step.
At the same time I totally understand if this is too much work for you and isn't worth your time and effort :/

It would be nice if you provided a SIP off version that would tweak the frameworks needed to be tweaked so it could work again, for more advanced users who want to do the extra step. At the same time I totally understand if this is too much work for you and isn't worth your time and effort :/

I second this! I disabled SIP (or parts of it can't remember) in order to disable a bunch of unwanted system frameworks. If you could still provide the native XDR brightness upscaling when SIP is disabled, please do!

It would be nice if you provided a SIP off version that would tweak the frameworks needed to be tweaked so it could work again, for more advanced users who want to do the extra step. At the same time I totally understand if this is too much work for you and isn't worth your time and effort :/

I second this! I disabled SIP (or parts of it can't remember) in order to disable a bunch of unwanted system frameworks. If you could still provide the native XDR brightness upscaling when SIP is disabled, please do!

The thing is, if I'm not mistaken, that even if he eventually find a way to disable the preset validations on ProDisplayLibrary.framework and/or other frameworks and make native XDR upscaling work again, because this will happen by modifying those frameworks that are inside the dyld cache file, which is signed by Apple if I'm not mistaken, every macOS update would brake it and the patch will have to be applied again. Personally, if that's the only way to have back this amazing feature that truly upgrades my MacBook, and if the way to patch it after every update isn't that hard, I totally accept the trade off!

Yes, this is a different approach, not used by the app yet (or any other app afaik). However it works best when the display is not on EDR mode, so if I implemented this I'd activate a preset that disables EDR altogether.

Anyway, this is not something I am working on right now, I just did some superficial testing and seems to work fine. But I think I'll then introduce a terminal-only command to enable this in an upcoming version so it flies under the radar but can be useful for those who really need it for any reason + to gather some feedback.

(note: just a minor correction, software upscaling - using color table - does not use a full screen HDR overlay, but must switch the display into EDR mode - the only standard way is to have some - even invisible - HDR content on screen).

Looking forward to that update man!

@Simos805 I agree completely. There really should be an ambient light sensor on the BACK of the display, not the front, because that's what our eyes are seeing! I constantly need to work in an environment where I'm right in front of a bright window, and so I need the high brightness, even more so than the 1000 nits that a newer Macbook would allow stock.

@waydabber If you have found another way to implement native brightness upscaling that behaves the same way it did before (not messing up HDR content), please let us test it!

Ironically, the new Studio Display XDR (which I ordered yesterday!) has ambient light sensors both front and back!

Just a note - I did not forget this (some other things took my focus, sorry). Right now it looks like the new upscaling method mostly works (on my 16" M3 Max, did not test with anything else) on 26.4.

The display must be put to the P3-600 nits preset and auto-brightness must be off (I wanted to create an appropriate preset for this that has all the right configuration, but sadly Apple further locked down things so now even Night Shift and some other basic features became incompatible with programmatically created presets in 26.4). The P3-600 is a HDR capable preset, so the upscaling will properly upscale HDR content as well without clipping - the only drawback is that macOS will tone-map HDR content as if the peak HDR brightness was 600 nits (while in reality this is remapped to the brightness the user select, up to the max 1000/1600nits).

I will experiment with this a bit more and try to make it into a nice, easy to use feature (it still has some rough edges) and provide an internal pre-release with it for testing (to see whether it works on the M4 and M5 as well).

Something seems to be off indeed. The "Supports HDR - No" is fine for the XDR display (this is reported as Yes for HDR capable third party external displays), as the EDR range seems to indicate that the display is otherwise EDR compatible (so it can show HDR content). But it is weird that Apple Display Presets are reported as unsupported. Did this ever work? Which app version are you using and what preset is configured for the display?

this issue was observed on the most recent app version (Version 4.2.2 Build 48115)

but after updating to the later 26.4 beta (beta 4) and restarting my laptop it seems to be detecting correctly; idk if it was a beta issue or just needed the restart? it has worked in the past too, yeah

But why it happens only with auto brightness turned off? (I refer only to the SDR content upscaling). It seems to me more like a bug.

As for the HDR content, yes I know that right now with the software upscaling method it clips, and that’s sad… Looking forward to the solution you mentioned above, but if it requires auto brightness to stay off and the HDR tone mapping goes only up to 600nits, it won’t be perfect either…

Ahh, that. Well, yes, I am not really sure whether it's a feature or a bug, but since one of the macOS Tahoe 26 versions, when auto brightness and color table adjustments are both enabled, rather strange things happen. With auto brightness, instead of letting only the SDR luminance range pass through the modified color table and leave the HDR clipped, macOS takes the entire EDR range and gamma (SDR+HDR) and kinda filters that through the color table (which should be mapped to the peak SDR value, that is 1.0), using the color table values as multipliers.

This might be in one sense a good thing, as right now with this macOS bug (feature?) with auto brightness enabled you can use software color table upscaling without a hard HDR clipping (but luminance levels that are tone mapped to be at or above around 1000 nits get crushed, that's the upscaling-level dependent clipping you see). However I am no sure whether this is intentional or a bug (I think the latter, as the same behavior does not happen with auto brightness disabled + with auto brightness sometimes the color table remains somehow misaligned even when upscaling is turned off and the display returns into non-EDR mode, causing gamma/contrast issues). Logically this is not a good as the gamma table should match the SDR range of the color profile (although XDR displays don't really use color profiles) - filtering the entire HDR gamma through the color table this way is not a valid step and is inconsistent with non-HDR displays (or even the XDR display with auto brightness off). I think for a predictable result it's best to simply disable auto-brightness and expect clipping. Also, Apple did not update any documentation to the related functions to indicate that the color table transfer functions should now work differently in Tahoe (but only with auto brightness enabled).

The app could of course accommodate (or exploit) this behavior and apply an upscaling curve with the idea of the color table array is being used as a multiplier transformation for entire HDR gamma - this would create a software upscaling that could show proper HDR content. But I am not sure if it is a good idea to rely on this as Apple can fix this bug (if it is a bug) any time.

Okay I see, but right now the problem is that we can’t use better display software upscaling even on SDR content with auto brightness turned off, and that’s a problem sometimes because as you know, in certain situations when the ambient brightness fluctuates enough (on a semi-cloudy day for example) this combined with the software upscaling results in sudden brightness drops, so in those situations turning the auto brightness off would make user experience better but with this problem, turning the auto brightness off isn’r an option.
Ahh I miss the native XDR upscaling…

Well, you can cover the ambient light sensor with a tape (to prevent brightness fluctuations and the related usual slowdowns the triggered didChangeScreenParametersNotification cause system-wide), then enable auto brightness and crank up the brightness all the way to 1600 nits using upscaling + enjoy the above-described bug's side effect of not having a clipped HDR range. :)

(alternatively you can turn off auto-brightness and use Metal fro upscaling, that does not do the clipping thing, but has other issues).

This is an experimental option that should be available in the next internal pre-release. It would be nice to gather some feedback how well this works on various MacBook models:

The discussion should continue here:

#5242

Hi, just to confirm, is this new experimental feature from #5242 only for MBP displays? (I skimmed through that issue but was a little unclear to me, so sorry if I missed it!) Just wanted to double check as I don't see it on my SDXDR after the update (and also tried updating to the latest internal 4.4.0 too). SD XDR + SD (non-XDR) + Mac Mini M4 Pro + macOS 26.5.
Thanks! :)

Yes, it is. The standard brightness upscaling works very well on the SDXDR though (I am using it as well).