Content Adaptive Brightness Control In Windows

[Danny Hosford]

Ihave a Lenovo Yoga C940-15IRH (81TE) laptop running Windows 10 that automatically adjusts the brightness of the display based on the content being displayed; however, when the screen displays white content [Wikipedia page], the brightness increases, and when the screen displays black content [website in dark mode], the brightness decreases.

I have a Yoga C940-15IRH and managed with these steps to turn off the behaviour you describe. But I don't think this solution is limited to that PC model. Rather, OEM display drivers sometimes have strange options turned on, and with the described steps you can reset such behaviours.

Monitors various sensors in order to expose data and adapt to system and user state. If this service is stopped or disabled, the display brightness will not adapt to lighting conditions. Stopping this service may affect other system functionality and features as well.

For my laptop (also a Lenovo) after trying all of the cmd commands and messing with adaptive brightness the only thing that helped was turning of "Use HDR" in Windows display settings. Hope that's the case for you too.

Open this command center, click on system, then click the Power tab. Check every toggle switch 'on', then turn them all off again starting with the bottom (enhanced power saving). I don't know why this worked for me, but it did.

I bought Inspiron 5510 last week (windows 11) and it has content adaptive brightness turned on (or auto brightness). I tried many things but nothing seems to work. I don't have any option to change it in settings, control panel, intel graphics command center. My laptop is updated, graphics driver is updated and I don't know what to do next?

I tried asking it on Microsoft forum but it went in vain. I tried contacting dell technical support explained everything to 3 representatives but everyone kept confirming my details, kept me waiting for minutes and then nothing, my call dropped in between and they didn't even call back after confirming my mobile phone. I'm literally tired of all this, I'm just cursing myself why I bought the laptop? I tried googling the stuff but they are making changes in registry directory which I think might create issues in future and is not suggested.

This in a Intel graphic thing. So go in the "Intel Graphics Command Center", left menu: "System", last tab "power" and you should find an energy economy setting toggle button (the one with an associated slider). I've just disabled this "feature" and now brightness is stable.

Note for Dell: since I have my laptop, I had many issues. Defective trackpad, replaced but then broken hardware (screen pivot axis, backplate internal plastic stuff) by those who replaced the trackpad on both machines I struggled to find that awful adaptive brightness stuff. But the worst part of that poor Inspiron experience, every time I ended up on that forum, I see the frustration of people trying to just use their machine, and you ignore us. The machine can't go to sleep mode while charging? No answer. Broken trackpad? No answer. Display issues? No answer. Why should we buy your machines if you totally let down peoples after that? the client 'support' is a nice waste of time.That would be a joke but it not even funny.

I had this problem with my 7506 which is just over a year old now. There were no settings that could turn off the Adaptive Brightness feature -- even though settings, BIOS, adapter properties might make you think so.

Man you saved me. It's their problem not noticing this annoying brightness change. Now I just closed the display power savings and leave adaptive brightness and panel self refresh on. Works fine so far.

Adaptive brightness is the screen brightness set automatically by the system in response to the ambient light sensor reading. Adaptive brightness provides users a more responsive display experience where brightness adapts automatically to the user's environment.

The implementation for auto-brightness has been radically simplified for OEMs wishing to integrate light sensors into Windows 11 using a new paradigm, a bucketized ambient light response (ALR) curve. For more information, see Ambient light response curve changes for Windows 11.

Windows detects the type of brightness interface exposed by the display driver and selects the most appropriate one. If a display driver only exposes the DXGK_BRIGHTNESS_INTERFACE_2 interface, the system will control brightness using percentage values. If a display driver exposes the DXGK_BRIGHTNESS_INTERFACE_3 interface, Windows 10, version 1809 and later controls brightness using nits values. The DXGK_BRIGHTNESS_INTERFACE_3 interface is ignored on down-level Windows versions. If both DXGK_BRIGHTNESS_INTERFACE_2 and DXGK_BRIGHTNESS_INTERFACE_3 interfaces are exposed by the display driver, Windows 10, version 1809 and later will control brightness using nits values. Down-level Windows versions will control brightness using percentage values.

If the system supports setting brightness in nits by having the display drive expose the DXGK_BRIGHTNESS_INTERFACE_3 interface, the display should be properly calibrated. Calibration should be performed at various intensities by measuring nits values with a high-quality nits meter at different locations of the display while displaying a white background. Tools to measure display brightness are called luminance meters or brightness meters, and are available for purchase from electronic equipment vendors and online retailers.

Starting with Windows 10, version 1809, the system will control brightness using nits on devices which display driver exposes the DXGK_BRIGHTNESS_INTERFACE_3 interface. The nit (candela per square meter) is an International System of Units (SI) unit of luminance. When a device bears a properly calibrated display and properly calibrated sensor, brightness control should work out of the box. There is no need for any ALR curve on these devices.

For these systems, it is critical that light sensors and display are accurately calibrated. Windows 10, version 1809 tolerates small inaccuracies that may occur during the manufacturing process of these systems. Placement of the components, glass transparency, and similar factors can greatly influence the lux and nits. Therefore, calibration on nits-based brightness systems should be done at least once with the final form factor design as opposed to doing calibration on development form factors and applying the result to the final form factor.

Systems that don't support nits brightness control must support percentage values. On percentage systems, a mapping between the backlight percentages and luminance values is necessary. The mapping of backlight percentages to luminance values should follow an exponential pattern. On nits-based brightness systems, since the each nit level is expected to be calibrated, an inbox percentage to nits mapping is provided. This inbox percentage to nits mapping uses human vision and color science research to provide a perceptually linear brightness slider. As long as the nit levels are calibrated correctly as described in DXGK_BRIGHTNESS_INTERFACE_3, the perceptual luminance difference between zero percent and 1% will be automatically equivalent to the perceptual luminance difference between 1% and 2%, and so forth.

Human vision is more sensitive to small changes in screen brightness output at low light levels, thus more backlight levels should be allocated to the lower brightness range to accommodate smoother transitions. The difference between 1% and 2% in nits should be smaller than the difference from 10% and 11%, for example. This means that 50% of the screen's maximum luminance will not be mapped to the 50% backlight level.

For an acceptable user experience, the lowest level of brightness (0%) must result in a low, but readable display. Users can get into inextricable situations when setting brightness to 0% on devices that map that value to 0 nits, as the controls to brighten the screen are not visible anymore. The screen must be bright enough at 0% for the user to interact with the UI on the display. On devices supporting the DXGK_BRIGHTNESS_INTERFACE_3 interface, 0% is automatically restricted to a minimum of 5 nits by Windows.

The following image compares changes to the default ALR curve from Windows 10 to Windows 11. An example of a default curve is on the left, and a bucketized default curve for Windows 11 is on the right. The curves illustrated below are only examples of curves that could be set as defaults. The actual default curve for a device depends on a number of factors and can vary depending on the device manufacturer.

Systems upgrading from Windows 10 to Windows 11: No changes to hardware or firmware outside of existing Windows 10 adaptive brightness requirements, these are internal changes to Windows 11. Existing Windows 10 adaptive brightness capable systems will experience the new bucketized curve when updated to Windows 11.

To reduce frequent display brightness fluctuations in response to fluctuating readings from the ALS, we introduced bucketed auto brightness. A range of lux values are mapped to a single target brightness percentage value. The display brightness is then transitioned to the target percentage value. On DXGK_BRIGHTNESS_INTERFACE_2 interface-based devices, the target percentage is used as it is. On DXGK_BRIGHTNESS_INTERFACE_3 interface-based devices, the target percentage is converted into the corresponding nits value and used. Based on our experiments under various lighting conditions, the lux ranges are partitioned into seven different overlapping buckets and assigned a corresponding display brightness target. A reading from the ALS is mapped to a target brightness using this look up table. The buckets introduce the necessary hysteresis effect that prevents fluctuations in the display brightness for non-significant changes in ALS readings. Overlapping buckets help with smooth transitions between the buckets when the ALS reading changes widely.

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