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Actually the whole screen is HDR, but the non-HDR parts are dimmed to match their normal brightness. They can do this because they calibrate their displays and

by Joeri 3y ago

Actually the whole screen is HDR, but the non-HDR parts are dimmed to match their normal brightness. They can do this because they calibrate their displays and know exactly how bright they are. By the way, if brightness is not maxed this works even on the 400 nits macbook air m1, which they call EDR. They ramp up to max brightness and dim the non-HDR parts.

mrtksn 3y ago
It works even if the brightness is maxed out(M1 Air), they must be leaving some brightness margin to allow for this to work on any brightness level - maybe except for outdoor lighting conditions? I had to blast the ambient light sensor with my phone's flash to get the screen bright enough so that the HDR content disappears. When the auto-brightness is turned off, you can still see the HDR content up until the top settings, just one bar down is enough to display it. The switch from SDR to HDR is also interesting, when an HDR content is to be displayed it slowly fades into HDR. It must be tamping up the backlight of the LCD when tinting the SDR content simultaneously to create the gradual brightness increase effect in the HDR areas. The fact that the SDR area doesn't flicker when this happens, gives me the impression that the Apple do amazing screen calibration.
- crazygringo 3y ago
  > It works even if the brightness is maxed out(M1 Air) No it doesn't, I'm trying it out right now on my M1 Air. If my screen brightness is max, the video isn't extra-bright in Chrome or in Safari. If I turn down the screen brightness, it does stand out. I don't know what you're talking about having to "blast the ambient light sensor" to get your screen to max brightness, that's not how my M1 Air works and it's not how any Mac laptop is supposed to work. That's used for "Automatically adjust brightness" (which I have on) but that's overridden at any moment just by using the brightness buttons on your keyboard to turn it up to the max. So I'm not sure how you think you've got your brightness "maxed out" but it seems you don't. You might have some other setting preventing it, like automatic screen dimming in battery mode.
  - mrtksn 3y ago
    Check this out: https://dropovercl.s3.amazonaws.com/3957bc45-20b7-47b5-8910-b97714592a6a/2a238380-2b06-4b46-824a-edf789b18202/7552ba33-e481-4f2d-a042-b57e3ce235fe.jpeg https://dropovercl.s3.amazonaws.com/3957bc45-20b7-47b5-8910-... Also, try not to get worked up for such stuff on the internet. Yas it appears that when plugged to the wall, it does lose the HDR-white on max brightness. Still, even on max - 1, HDR is displayed properly. On iPhone 14 Pro, which has the ability to display full HDR content, also can't display the HDR-White when the brightness is cranked up to the max. In my book, M1 Air and iPhone 14 Pro are both capable of displaying HDR-white. Just don't go to absolute peak brightness, which only happens under direct sunlight anyway("blast the ambient light sensor" part, simulating extremely bright environment).
    - deleted 3y ago
      [deleted]
    - crazygringo 3y ago
      > Also, try not to get worked up for such stuff on the internet. Yas it appears that when plugged to the wall, it does lose the HDR-white on max brightness. Still, even on max - 1, HDR is displayed properly. Correcting misinformation isn't "getting worked up", please don't insinuate anything like that. HDR is still fairly new so it's important that misinformation doesn't spread. And as your comment suggests, it's only because your Mac is temporarily reducing its brightness in battery mode (also sometimes due to heavy CPU usage, that the battery can't fully drive the display and chips). But your assertion that "absolute peak brightness... only happens under direct sunlight" is false. As you yourself are seeing, you achieve the same when merely plugged in, no ambient light required.
      - deleted 3y ago
        [deleted]
jimnotgym 3y ago
Hang on, Apple don't calibrate each display individualy. They profile a characteristic display, and then apply that characteristic profile to all of their displays. If you want a calibrated display you will need to buy some calibration hardware! Displays change over time too...so frequent calibration is needed. Edit: If you want to prove this to yourself grab the display profile off another mac and compare it. It will be the same.
- Joeri 3y ago
  TIL Anyway, the profile is accurate enough that the dimming of non-HDR parts while ramping up brightness is not noticeable to me if I block off the HDR part.

by Joeri 3y ago

mrtksn 3y ago

It works even if the brightness is maxed out(M1 Air), they must be leaving some brightness margin to allow for this to work on any brightness level - maybe except for outdoor lighting conditions? I had to blast the ambient light sensor with my phone's flash to get the screen bright enough so that the HDR content disappears. When the auto-brightness is turned off, you can still see the HDR content up until the top settings, just one bar down is enough to display it. The switch from SDR to HDR is also interesting, when an HDR content is to be displayed it slowly fades into HDR. It must be tamping up the backlight of the LCD when tinting the SDR content simultaneously to create the gradual brightness increase effect in the HDR areas. The fact that the SDR area doesn't flicker when this happens, gives me the impression that the Apple do amazing screen calibration.

crazygringo 3y ago
> It works even if the brightness is maxed out(M1 Air) No it doesn't, I'm trying it out right now on my M1 Air. If my screen brightness is max, the video isn't extra-bright in Chrome or in Safari. If I turn down the screen brightness, it does stand out. I don't know what you're talking about having to "blast the ambient light sensor" to get your screen to max brightness, that's not how my M1 Air works and it's not how any Mac laptop is supposed to work. That's used for "Automatically adjust brightness" (which I have on) but that's overridden at any moment just by using the brightness buttons on your keyboard to turn it up to the max. So I'm not sure how you think you've got your brightness "maxed out" but it seems you don't. You might have some other setting preventing it, like automatic screen dimming in battery mode.
- mrtksn 3y ago
  Check this out: https://dropovercl.s3.amazonaws.com/3957bc45-20b7-47b5-8910-b97714592a6a/2a238380-2b06-4b46-824a-edf789b18202/7552ba33-e481-4f2d-a042-b57e3ce235fe.jpeg https://dropovercl.s3.amazonaws.com/3957bc45-20b7-47b5-8910-... Also, try not to get worked up for such stuff on the internet. Yas it appears that when plugged to the wall, it does lose the HDR-white on max brightness. Still, even on max - 1, HDR is displayed properly. On iPhone 14 Pro, which has the ability to display full HDR content, also can't display the HDR-White when the brightness is cranked up to the max. In my book, M1 Air and iPhone 14 Pro are both capable of displaying HDR-white. Just don't go to absolute peak brightness, which only happens under direct sunlight anyway("blast the ambient light sensor" part, simulating extremely bright environment).
  - deleted 3y ago
    [deleted]
  - crazygringo 3y ago
    > Also, try not to get worked up for such stuff on the internet. Yas it appears that when plugged to the wall, it does lose the HDR-white on max brightness. Still, even on max - 1, HDR is displayed properly. Correcting misinformation isn't "getting worked up", please don't insinuate anything like that. HDR is still fairly new so it's important that misinformation doesn't spread. And as your comment suggests, it's only because your Mac is temporarily reducing its brightness in battery mode (also sometimes due to heavy CPU usage, that the battery can't fully drive the display and chips). But your assertion that "absolute peak brightness... only happens under direct sunlight" is false. As you yourself are seeing, you achieve the same when merely plugged in, no ambient light required.
    - deleted 3y ago
      [deleted]

jimnotgym 3y ago

Hang on, Apple don't calibrate each display individualy. They profile a characteristic display, and then apply that characteristic profile to all of their displays. If you want a calibrated display you will need to buy some calibration hardware! Displays change over time too...so frequent calibration is needed. Edit: If you want to prove this to yourself grab the display profile off another mac and compare it. It will be the same.

Joeri 3y ago
TIL Anyway, the profile is accurate enough that the dimming of non-HDR parts while ramping up brightness is not noticeable to me if I block off the HDR part.