4K resolution
As noted above, DCI 4K is 40962160, while 4K UHD is 38402160, producing a slight difference in aspect ratio rather than a significant difference in resolution. Traditional displays, such as LCD or OLED, are 3840 pixels across the screen, with each pixel being 1/3840th of the screen width. They do not overlap—if they did, they would suffer reduced detail. The diameter of each pixel is basically 1/3840th of the screen width or 1/2160th of the screen height - either gives the same size pixel. That 38402160 works out to 8.3 megapixels, the official resolution of 4K UHD (and therefore Blu-ray UHD discs).
SES S.A.
In May 2018 SES broadcast an 8K television signal via its satellite system for the first time, as part of its Industry Days conference at the Luxembourg HQ. The 8K demonstration content, with a resolution of 7680x4320 pixels, a frame rate of 60 frames per second and 10-bit colour depth, was encoded in HEVC and transmitted at a rate of 80 Mbit/s via the Astra 3B satellite.