A television system that provides a substantially higher image resolution than the previous generation of technologies, known as High Definition Television (HDTV). The term has been used since 1936; more recently, it refers to the generation following standard-definition (SD) television. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television, and Blu-ray Discs.
History and Evolution
The term HDTV has been used since at least 1936. In more recent times, it refers to the generation following standard-definition television (SDTV). High-definition digital television was impossible with uncompressed video, which requires a bandwidth exceeding 1 Gbit/s for studio-quality HD digital video. Digital HDTV was made possible by developing discrete cosine transform (DCT) video compression.
- DCT coding: A lossy image compression technique first proposed by Nasir Ahmed in 1972. It was later adapted into a motion-compensated DCT algorithm for video coding standards such as the H. 26x formats from 1988 onwards and the MPEG formats from 1993 onwards.
Types of HDTV
There are two main types of HDTV: 720p and 1080p.
- 720p: Has a resolution of 1280 x 720 pixels. Often referred to as standard HD.
- 1080p: Has a resolution of 1920 x 1080 pixels. Often referred to as full HD.
Transmission and Playback
HDTV can be transmitted over various media, including cable, satellite, terrestrial broadcast, and Internet. It can also be played back on various devices, including Blu-ray players, set-top boxes, and computers.
