Author here: I hear you. I had to double check a bunch of time whether you can get HDR with 8-bit displays. It seems like not all TV panels out there are 10-bit and they still claim to support HDR.
That's why I played the Spears and Munsil test pattern video with a 8-bit and 10-bit pattern on the same video. The 10-bit pattern was smooth which convinced me that it was outputting 10-bit signal. I also confirmed the TV and monitor I used has a 10-bit panel (not 8-bit + FRC).
> monitor preferences and look for 10-bit or 422 or 444. If you see 420 or 8-bit
I tried the monitor info but didn't find this information. Neither in the TV info. Also Apple hides this information in their System Report.
If you have other tests in mind, I'm happy to test more and get to the bottom of this :)
If you have an LG OLED TV you can push 11111 over the Channels > Channel Tuner menu (I think? Google this if it doesn’t work) and it will show you a screen of input stats. If you use the arrow keys and OK buttons you can open an HDMI sub-menu which shows you the input signal as 8-bit or 10-bit. Via a Club3D DP1.4 to HDMI 2.1 adapter I was only able to get 8-bit HDR according to the LG TV. Your other monitors might tell you more details maybe? I’m away from my setup but I could post a photo later and more details on the connections and cables. I tried 3 different USB C DisplayPort adapters with the same results on each... I plan to test what the LG TV says for an Nvidia 2060 soon too, to compare...
True HDR needs local dimming, so very few monitors outside of mini leds, oleds, and reference displays have large amounts local dimming, but it is coming to consumer displays.
That's why I played the Spears and Munsil test pattern video with a 8-bit and 10-bit pattern on the same video. The 10-bit pattern was smooth which convinced me that it was outputting 10-bit signal. I also confirmed the TV and monitor I used has a 10-bit panel (not 8-bit + FRC).
> monitor preferences and look for 10-bit or 422 or 444. If you see 420 or 8-bit
I tried the monitor info but didn't find this information. Neither in the TV info. Also Apple hides this information in their System Report.
If you have other tests in mind, I'm happy to test more and get to the bottom of this :)