Please tell us some basic information before asking for help:
Model Name: -Returned-
Firmware Version: -latest Indian firmware-
Rooted or not: NOT
Frequency of Occurrence: FREQUENT
APP Name & APP Version (If your issue relates to the app): Color Calibrator
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
If you are reading this (after a 100 other threads about this), you are probably extremely frustrated with the heavy black crush issue of this phone in Youtube/Netflix videos which still hasn't been completely fixed by ASUS. Although ASUS should permanently fix this but here is a temporary fix that seems to work well and should not bother after a while (although no excuse for ASUS to not fix this!!).
Download the "Color Calibrator" app from Google Play Store and fix the settings for the gamma overlay as below (seems just about right after testing this 100+ times at different brightness level with different 4K and 4K HDR videos).
Pros: Black crush is no more visible (atleast 99.5% of the time it is not!).
Cons: Display colors (may) seem washed out for a while (just like when you would tweak colors from the Splendid app, you just need some time for your eyes to adjust). You'll surely get adjusted to this in no time since it fixes the problem for good!
PS: Kindly don't accuse/blame me for anything. If it doesn't work for you/if you don't like it, simply don't use it and uninstall. I don't have this phone with me anymore (returned due to other display issues) but sharing this with the community hoping it serves good for someone out there. 🙂
Please do respond if it worked for you or not. You may still have to tweak the gamma slider a bit here-n-there to suit your needs.