In plain language
A colour space defines which colours a signal can describe. The old standard, Rec.709, covers a modest range. BT.2020 — also written Rec.2020 — covers a much wider one, and is the container for UHD and HDR.
No consumer display reproduces all of BT.2020. In practice content is mastered inside a smaller target, usually DCI-P3, and carried in the BT.2020 container.
Why it matters in your setup
What the display is told about the colour space determines how it interprets every value it receives. Get the container wrong and colours shift — typically over-saturated, with skin tones going red.
This is precisely the LLDV primaries trap: send DCI-P3 to a display expecting BT.2020 and it applies the wrong interpretation to the correct data.
What the DR HDMI 8K does with it
A large part of the DR HDMI 8K's EDID library is explicitly BT.2020: 4K60, 4K50, 4K30, 4K24 and 1080p tables in BT.2020 with and without HDR. In the Dolby Vision section, BT.2020 is one of the selectable primaries, and it is usually the right answer when LLDV colours look over-cooked.
Need the hardware?
Open the DR HDMI 8K product page on HDfury.uk.