To add some more examples:
This is how PC mode on a LG C9 looks like with Video Transfer Rate set to -1 and HDR turned on (= PS5 uses 4:2:2 Chroma Subsampling and therefore falls back to TMDS):
Notice that ugly color banding? Yes. That is what you are getting when you are using HDR with the PC Label
with a device that does not support FRL (e.g. every HDMI 2.0b device like the PS4 PRO or RTX 2080 Ti).
This is how it looks like when you are using 4K Tranfer Rate "Auto". Which means that the PS5 now outputs at 444, thus requiring to use FRL.
Much better, right? Yes. That is how this image should look like. The only thing we changed is the method
the PS5 uses to output the image (FRL instead of TMDS). Before you ask: Yes, below the Astro's Playroom Icon there is still a tiny imperfection. But I guess this is baked into the image. Probably artifacts that were introduced after the compression of the image.
Now let us see how both images compare to the console label:
Much better than the first image. But basically no difference between the image where FRL is used. In real life I cannot see any difference at all. You might see some slight differences on these images. But they are most likely caused by my camera. Which means that the last two images basically look the same.
So what does that tell us?
The first thing to note for LG OLED owners: This issue is present if:
- HDR is turned on (in SDR you should not have any issues whatsoever)
- PC Label is selected
- You are using a source device with HDMI 2.0(a|b) (e.g. PS4 PRO/RTX 2080).
- You are using a source device with HDMI 2.1, but it does not use FRL for some settings and therefore falls back to TMDS.
tl;dr If you are using a device like PS4 PRO/RTX 2080 do not use the PC Label for HDR.
On PC you might want to use it in SDR. But avoid it for HDR content.
If you are using a PS5, RTX 2080 Ti or something similar that will output stuff using FRL
you are fine and can use the PC Label even in HDR.