What is YCbCr?

In plain language

Y is luma, the brightness. Cb and Cr carry the colour difference. Because human vision is much more sensitive to brightness than to colour detail, the colour channels can be sent at lower resolution — which is exactly what 4:2:2 and 4:2:0 do.

YUV is the older name and is still used interchangeably; YUV422 on a specification sheet means YCbCr 4:2:2.

Why it matters in your setup

Essentially all video content is YCbCr, so a display or receiver expecting it and getting RGB (or the reverse) can produce shifted colours or wrong black levels. Sources usually negotiate this correctly; when they do not, forcing the format on the source is the fix.

It also matters for Dolby Vision: YUV422 12-bit support is a specific capability flag, separate from everything else.

What the DR HDMI 8K does with it

The DR HDMI 8K's Dolby Vision data block builder has an explicit YUV422 12-bit switch, and its EDID tables specify the chroma format for every entry. The OLED reports the colour space the link actually settled on, so you can confirm rather than assume.