Ultra High Definition Television has two picture sizes, correctly referred to as UHD-1 (4K) and UHD-2 (8K), though more commonly known as 4K UHD and 8K UHD respectively. Both are standardized in ITU-R.BT. 2020.
The 4K UHD image is four times the area of 1920 HD at 3840 x 2160. There is now a choice of equipment for 4K UHD production and a number of programs have been produced in the format. 4K UHD TV screens are widely available; transmission trials have proved the delivery system using HEVC video compression via DVB.
What is now known as 8K UHD started life as Super-Hi vision in the laboratory at NHK in about 2001. The picture size is 7680 x 4320 – 16 times the area of 1920 HD. There are plans for transmission in Japan.
ITU-R BT.2020 describes framerates from 23.98 to 120 Hz with only progressive scans and a wider color gamut which can reproduce richer colors than HD. The 4K format has already been used for a number of broadcasts. For sport the 50 or 60 Hz framerate is popular. Even at lower rates the format produces very large quantities of data that require faster video links and more storage than HD. This requirement is four times larger with 8K.