Bug 509664

Created attachment 185068 [details]
Clouds look overexposed when SDR brightness is set to 200, while looking good at 400

SUMMARY

After upgrading to 6.5 Beta 1, HDR contents in Chrome Beta seem to be broken as their max brightness is capped to the SDR brightness.

I have a monitor with peak brightness at 430 nits, and for video https://www.youtube.com/watch?v=VLdj9ZwpKfo&t=706s, the most noticeable thing is that clouds in the background are almost overexposed when SDR brightness is set to 200.

STEPS TO REPRODUCE
1. Install Chrome Beta and enable HDR in System Settings
2. Go to the video https://www.youtube.com/watch?v=VLdj9ZwpKfo&t=706s
3. Change the SDR brightness for the HDR monitor

OBSERVED RESULT

Clouds in the background look overexposed when SDR brightness is set to 200

EXPECTED RESULT

Clouds shouldn't look overexposed 

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.4.90
KDE Frameworks Version: 6.18.0
Qt Version: 6.10.0
Kernel Version: 6.16.7-2-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 20 × 12th Gen Intel® Core™ i7-12700H
Memory: 32 GiB of RAM (31.0 GiB usable)
Graphics Processor 1: NVIDIA GeForce RTX 3060 Laptop GPU
Graphics Processor 2: Intel® Iris® Xe Graphics

ADDITIONAL INFORMATION

Other affected HDR contents:
- https://www.testufo.com/hdr
- https://www.wide-gamut.com/test/image-hdr