Ultra-high-definition television today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed by NHK Science & Technology Research Laboratories and later defined and approved by the International Telecommunication Union (ITU). It is a digital television (DTV) standard, and the successor to high-definition television (HDTV), which in turn was the successor to standard-definition television (SDTV).
