HDTV ,DVD and BD are mastered to bt709 /100 NITS and an average movie theater is ~ 45 UNITS hence the need for dark/black walls to keep light reflections from walls off the screen .
Full HDR TV is ~ 800 -1200 NIT brightness highlights and most PC screens are 300 NIT or less . HDTV t can range from ~200 NIT to 400 NIT ,Consumer HDR TV and media content is mastered (up to ) 1000 NITS .
ATSC ,( other regional HDTV broadcasts in general and 4K SDR ) ,Blue Ray ,modern DVD and other HDTV formats and many content websites use bt709 8 bit color and 4:2:0 chroma video levels at 100 NIT content mastering and 65D white color temp .
The 4:2:0 SD/HDTV/SDR 4K consumer content is mastered accordingly to bt709 and TV sets and PC displays (outside of wide color gamut ) ideally should be calibrated to bt709 or RGB .016--~238 video levels . bt709 is an 8 bit color ITU standard as is ATSC .bt.709 white is D65 or 6500 K
https://en.wikipedia.org/wiki/RGB_color_space
OTOH there is often creative licence within the bt709 or wider color spaces hence blue or sepia tinted movies or warm or cool video for 4 examples ..
Digital theater packages for theaters , HDR content and mastering & UHD Blue Ray ,HDR10 and DV and downloads are mastered to DCI P-3 10 bit color for wide color gamut HDR TV's and movie theaters . The old scan line NTSC SDTV was a narrower color gamut
There are no films left in mainstream movie /TV production / distribution and theaters although some movies may be filmed and digitally re mastered to a 2K intermediate or something below a 4K intermediate ~ 3.5 K for 35mm . Some 4K consumer content is only upscaled from a 2K intermediate also........ it's caveat emptor when buying 4K content which can be (up to ) 4K at HDR _10 / HDR DV or both like a UHD HDR WCG BD from the production digital intermediate to the media ☺
OTOH my 4K Sony Triluminous wide color gamut XBR HDR TV can competently upscale & remaster 8 bit bt709 HDTV to a convincing nearly DCI-P3 10 bit wide color gamut for the wide color gamut 10 bit panel.and it looks real good.
Regular 8 bit color gamut and some 10 bit conventional
LED /LCD panels for PC and HDTV and SDR 4K can't make good colors or primaries due to the
conventional LED light spectrum a wide color gamut LED panel gets around that . We can see 14 bit color so TV and PC's have a long way to go .☺