HOME

TheInfoList



OR:

High-definition television (HD or HDTV) describes a
television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...
system which provides a substantially higher
image resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how cl ...
than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the generation following
standard-definition television Standard-definition television (SDTV, SD, often shortened to standard definition) is a television system which uses a resolution that is not considered to be either high or enhanced definition. "Standard" refers to it being the prevailing s ...
(SDTV), often abbreviated to HDTV or HD-TV. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television,
cable television Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with bro ...
,
satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commo ...
and
Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of stor ...
s.


Formats

HDTV may be transmitted in various formats: *
720p 720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcas ...
(1280 horizontal pixels × 720 lines): 921,600 pixels *
1080i 1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the screen ...
(1920×1080)
interlaced Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. Thi ...
scan: 1,036,800 pixels (~1.04 MP). *
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ver ...
(1920×1080) progressive scan: 2,073,600 pixels (~2.07 MP). ** Some countries also use a non-standard CEA resolution, such as 1440×1080i: 777,600 pixels (~0.78 MP) per field or 1,555,200 pixels (~1.56 MP) per frame When transmitted at two megapixels per frame, HDTV provides about five times as many pixels as SD (standard-definition television). The increased resolution provides for a clearer, more detailed picture. In addition, progressive scan and higher frame rates result in a picture with less flicker and better rendering of fast motion. HDTV as is known today first started official broadcasting in 1989 in Japan, under the
MUSE In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in th ...
/Hi-Vision analog system. HDTV was widely adopted worldwide in the late 2000s.


History

The term ''high definition'' once described a series of television systems originating from August 1936; however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30 lines of resolution. The ongoing competition between companies and nations to create true "HDTV" spanned the entire 20th century, as each new system became higher definition than the last. In the 2010s, this race has continued with 4K, 5K and 8K systems. The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems. The Baird system was discontinued in February 1937. In 1938 France followed with its own 441-line system, variants of which were also used by a number of other countries. The US
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable. All of these systems used interlacing and a 4:3 aspect ratio except the 240-line system which was progressive (actually described at the time by the technically correct term "sequential") and the 405-line system which started as 5:4 and later changed to 4:3. The 405-line system adopted the (at that time) revolutionary idea of interlaced scanning to overcome the flicker problem of the 240-line with its 25 Hz frame rate. The 240-line system could have doubled its frame rate but this would have meant that the transmitted signal would have doubled in bandwidth, an unacceptable option as the video baseband bandwidth was required to be not more than 3 MHz. Color broadcasts started at similar line counts, first with the US NTSC color system in 1953, which was compatible with the earlier monochrome systems and therefore had the same 525 lines per frame. European standards did not follow until the 1960s, when the
PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields ( ...
and
SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...
color systems were added to the monochrome 625-line broadcasts. The NHK (Japan Broadcasting Corporation) began conducting research to "unlock the fundamental mechanism of video and sound interactions with the five human senses" in 1964, after the Tokyo Olympics. NHK set out to create an HDTV system that ended up scoring much higher in subjective tests than NTSC's previously dubbed "HDTV". This new system, NHK Color, created in 1972, included 1125 lines, a 5:3 aspect ratio and 60 Hz refresh rate. The Society of Motion Picture and Television Engineers (SMPTE), headed by Charles Ginsburg, became the testing and study authority for HDTV technology in the international theater. SMPTE would test HDTV systems from different companies from every conceivable perspective, but the problem of combining the different formats plagued the technology for many years. There were four major HDTV systems tested by SMPTE in the late 1970s, and in 1979 an SMPTE study group released ''A Study of High Definition Television Systems'': * EIA monochrome: 4:3 aspect ratio, 1023 lines, 60 Hz * NHK color: 5:3 aspect ratio, 1125 lines, 60 Hz * NHK monochrome: 4:3 aspect ratio, 2125 lines, 50 Hz * BBC colour: 8:3 aspect ratio, 1501 lines, 60 Hz Since the formal adoption of
digital video broadcasting Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...
's (DVB) widescreen HDTV transmission modes in the mid to late 2000s; the 525-line
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
(and
PAL-M PAL-M is the analogue TV system used in Brazil since 19 February 1972. At that time, Brazil was the first South American country to broadcast in colour. Colour TV broadcast began on 19 February 1972, when the TV networks Globo and Bandeirantes t ...
) systems, as well as the European 625-line
PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields ( ...
and
SECAM SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...
systems, are now regarded as ''standard definition'' television systems.


Analog systems

Early HDTV broadcasting used analog technology, but today it is transmitted digitally and uses
video compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression ...
. In 1949, France started its transmissions with an 819 lines system (with 737 active lines). The system was monochrome only and was used only on VHF for the first French TV channel. It was discontinued in 1983. In 1958, the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
developed ''Тransformator'' (russian: Трансформатор, meaning ''Transformer''), the first high-resolution (definition) television system capable of producing an image composed of 1,125 lines of resolution aimed at providing teleconferencing for military command. It was a research project and the system was never deployed by either the military or consumer broadcasting. In 1986, the
European Community The European Economic Community (EEC) was a regional organization created by the Treaty of Rome of 1957,Today the largely rewritten treaty continues in force as the ''Treaty on the functioning of the European Union'', as renamed by the Lisbo ...
proposed HD-MAC, an analog HDTV system with 1,152 lines. A public demonstration took place for the
1992 Summer Olympics The 1992 Summer Olympics ( es, Juegos Olímpicos de Verano de 1992, ca, Jocs Olímpics d'estiu de 1992), officially known as the Games of the XXV Olympiad ( es, Juegos de la XXV Olimpiada, ca, Jocs de la XXV Olimpíada) and commonly known as ...
in Barcelona. However HD-MAC was scrapped in 1993 and the
Digital Video Broadcasting Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...
(DVB) project was formed, which would foresee development of a digital HDTV standard.


Japan

In 1979, the Japanese public broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio. The system, known as Hi-Vision or MUSE after its
multiple sub-Nyquist sampling encoding MUSE (Multiple sub-Nyquist Sampling Encoding), commercially known as Hi-Vision (a contraction of HIgh-definition teleVISION) was a Japanese analog HDTV system, with design efforts going back to 1979. It used dot-interlacing and digital video ...
(MUSE) for encoding the signal, required about twice the bandwidth of the existing NTSC system but provided about four times the resolution (1035i/1125 lines). In 1981, the MUSE system was demonstrated for the first time in the United States, using the same 5:3 aspect ratio as the Japanese system. Upon visiting a demonstration of MUSE in Washington, US President Ronald Reagan was impressed and officially declared it "a matter of national interest" to introduce HDTV to the US. NHK taped the
1984 Summer Olympics The 1984 Summer Olympics (officially the Games of the XXIII Olympiad and also known as Los Angeles 1984) were an international multi-sport event held from July 28 to August 12, 1984, in Los Angeles, California, United States. It marked the seco ...
with a Hi-Vision camera, weighing 40 kg. Satellite test broadcasts started June 4, 1989, the first daily high-definition programs in the world, with regular testing starting on November 25, 1991, or "Hi-Vision Day"dated exactly to refer to its 1,125-lines resolution. Regular broadcasting of BS-9ch commenced on November 25, 1994, which featured commercial and NHK programming. Several systems were proposed as the new standard for the US, including the Japanese MUSE system, but all were rejected by the
FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...
because of their higher bandwidth requirements. At this time, the number of television channels was growing rapidly and bandwidth was already a problem. A new standard had to be more efficient, needing less bandwidth for HDTV than the existing NTSC.


Decrease of analog HD systems

The limited standardization of analog HDTV in the 1990s did not lead to global HDTV adoption as technical and economic constraints at the time did not permit HDTV to use bandwidths greater than normal television. Early HDTV commercial experiments, such as NHK's MUSE, required over four times the bandwidth of a standard-definition broadcast. Despite efforts made to reduce analog HDTV to about twice the bandwidth of SDTV, these television formats were still distributable only by satellite. In Europe too, the HD-MAC standard was considered not technically viable. In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV (
Sony HDVS Sony HDVS is a range of high-definition video equipment developed in the 1980s to support an early analog high-definition television system (used in multiple sub-Nyquist sampling encoding (MUSE) broadcasts) thought to be the broadcast television ...
). Japan remained the only country with successful
public broadcasting Public broadcasting involves radio, television and other electronic media outlets whose primary mission is public service. Public broadcasters receive funding from diverse sources including license fees, individual contributions, public financing ...
of analog HDTV, with seven broadcasters sharing a single channel. However, the Hi-Vision/MUSE system also faced commercial issues when it launched on November 25, 1991. Only 2,000 HDTV sets were sold by that day, rather than the enthusiastic 1.32 million estimation. Hi-Vision sets were very expensive, up to US$30,000 each, which contributed to its low consumer adaption. A Hi-Vision VCR from
NEC is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network solu ...
released at Christmas time retailed for US$115,000. In addition, the United States saw Hi-Vision/MUSE as an outdated system and had already made it clear that it would develop an all-digital system. Experts thought the commercial Hi-Vision system in 1992 was already eclipsed by digital technology developed in the U.S. since 1990. This was an American victory against the Japanese in terms of technological dominance. By mid-1993 prices of receivers were still as high as 1.5 million yen (US$15,000). On February 23, 1994, a top broadcasting administrator in Japan admitted failure of its analog-based HDTV system, saying the U.S. digital format would be more likely a worldwide standard. However this announcement drew angry protests from broadcasters and electronic companies who invested heavily into the analog system. As a result, he took back his statement the next day saying that the government will continue to promote Hi-Vision/MUSE. That year NHK started development of
digital television Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advan ...
in an attempt to catch back up to America and Europe. This resulted in the
ISDB Integrated Services Digital Broadcasting (ISDB; Japanese: , ''Tōgō dejitaru hōsō sābisu'') is a Japanese broadcasting standard for digital television (DTV) and digital radio. ISDB supersedes both the NTSC-J analog television system and ...
format. Japan started digital satellite and HDTV broadcasting in December 2000.


Rise of digital compression

High-definition digital television was not possible with
uncompressed video Uncompressed video is digital video that either has never been compressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video monitors, video recording devices (including general-pur ...
, which requires a
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
exceeding 1
Gbit/s In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mul ...
for studio-quality HD
digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...
. Digital HDTV was made possible by the development of discrete cosine transform (DCT)
video compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression ...
. DCT coding is a
lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...
image compression Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior r ...
technique that was first proposed by Nasir Ahmed in 1972, and was later adapted into a motion-compensated DCT algorithm for video coding standards such as the
H.26x The Video Coding Experts Group or Visual Coding Experts Group (VCEG, also known as Question 6) is a working group of the ITU Telecommunication Standardization Sector (ITU-T) concerned with standards for compression coding of video, images, audio, ...
formats from 1988 onwards and the
MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and ...
formats from 1993 onwards. Motion-compensated DCT compression significantly reduces the amount of bandwidth required for a digital TV signal. By 1991, it had achieved
data compression ratio Data compression ratio, also known as compression power, is a measurement of the relative reduction in size of data representation produced by a data compression algorithm. It is typically expressed as the division of uncompressed size by compresse ...
s from 8:1 to 14:1 for near-studio-quality HDTV transmission, down to 70140 
Mbit/s In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mult ...
. Between 1988 and 1991, DCT video compression was widely adopted as the
video coding standard A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream). It typically uses a standardized video compression algo ...
for HDTV implementations, enabling the development of practical digital HDTV. Dynamic
random-access memory Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost th ...
(
DRAM Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxi ...
) was also adopted as
framebuffer A framebuffer (frame buffer, or sometimes framestore) is a portion of random-access memory (RAM) containing a bitmap that drives a video display. It is a memory buffer containing data representing all the pixels in a complete video frame. Modern ...
semiconductor memory Semiconductor memory is a digital electronic semiconductor device used for digital data storage, such as computer memory. It typically refers to devices in which data is stored within metal–oxide–semiconductor (MOS) memory cells on a sil ...
, with the DRAM
semiconductor industry The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. It formed around 1960, once the fabrication of semicondu ...
's increased manufacturing and reducing prices important to the commercialization of HDTV. Since 1972,
International Telecommunication Union The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union ...
's radio telecommunications sector (
ITU-R The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency s ...
) had been working on creating a global recommendation for Analog HDTV. These recommendations, however, did not fit in the broadcasting bands which could reach home users. The standardization of
MPEG-1 MPEG-1 is a standard for lossy compression of video and audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively) without excessive quality loss, making ...
in 1993 led to the acceptance of recommendations ITU-R BT.709. In anticipation of these standards, the Digital Video Broadcasting (DVB) organisation was formed. It was alliance of broadcasters, consumer electronics manufacturers and regulatory bodies. The DVB develops and agrees upon specifications which are formally standardised by
ETSI The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization in the field of information and communications. ETSI supports the development and testing of global technical standard ...
. DVB created first the standard for
DVB-S Digital Video Broadcasting – Satellite (DVB-S) is the original DVB standard for Satellite Television and dates from 1995, in its first release, while development lasted from 1993 to 1997. The first commercial applications was by Star TV in Asi ...
digital satellite TV,
DVB-C Digital Video Broadcasting - Cable (DVB-C) is the DVB European consortium standard for the broadcast transmission of digital television over cable. This system transmits an MPEG-2 or MPEG-4 family digital audio/digital video stream, using a QA ...
digital cable TV and
DVB-T DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Feb ...
digital terrestrial TV. These broadcasting systems can be used for both SDTV and HDTV. In the US the Grand Alliance proposed
ATSC Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that ...
as the new standard for SDTV and HDTV. Both ATSC and DVB were based on the
MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression metho ...
standard, although DVB systems may also be used to transmit video using the newer and more efficient H.264/MPEG-4 AVC compression standards. Common for all DVB standards is the use of highly efficient modulation techniques for further reducing bandwidth, and foremost for reducing receiver-hardware and antenna requirements. In 1983, the International Telecommunication Union's radio telecommunications sector (ITU-R) set up a working party (IWP11/6) with the aim of setting a single international HDTV standard. One of the thornier issues concerned a suitable frame/field refresh rate, the world already having split into two camps, 25/50 Hz and 30/60 Hz, largely due to the differences in mains frequency. The IWP11/6 working party considered many views and throughout the 1980s served to encourage development in a number of video digital processing areas, not least conversion between the two main frame/field rates using motion vectors, which led to further developments in other areas. While a comprehensive HDTV standard was not in the end established, agreement on the aspect ratio was achieved. Initially the existing 5:3 aspect ratio had been the main candidate but, due to the influence of widescreen cinema, the aspect ratio 16:9 (1.78) eventually emerged as being a reasonable compromise between 5:3 (1.67) and the common 1.85 widescreen cinema format. An aspect ratio of 16:9 was duly agreed upon at the first meeting of the IWP11/6 working party at the BBC's Research and Development establishment in Kingswood Warren. The resulting ITU-R Recommendation ITU-R BT.709-2 (" Rec. 709") includes the 16:9 aspect ratio, a specified
colorimetry Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...
, and the scan modes
1080i 1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the screen ...
(1,080 actively
interlaced Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. Thi ...
lines of resolution) and
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ver ...
(1,080 progressively scanned lines). The British
Freeview HD Freeview is the United Kingdom's sole digital terrestrial television platform. It is operated by Digital UK Ltd and DTV Services Ltd, a joint venture between the BBC, ITV, Channel 4, Channel 5 and Sky. It was launched on 30 October 2002, t ...
trials used MBAFF, which contains both progressive and interlaced content in the same encoding. It also includes the alternative 1440×1152 HDMAC scan format. (According to some reports, a mooted 750-line (720p) format (720 progressively scanned lines) was viewed by some at the ITU as an enhanced television format rather than a true HDTV format, and so was not included, although 1920×1080i and 1280×720p systems for a range of frame and field rates were defined by several US
SMPTE The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and executives working in the m ...
standards.)


Inaugural HDTV broadcast in the United States

HDTV technology was introduced in the United States in the early 1990s and made official in 1993 by the Digital HDTV Grand Alliance, a group of television, electronic equipment, communications companies consisting of
AT&T Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...
,
General Instrument General Instrument (GI) was an American electronics Manufacturing, manufacturer based in Horsham, Pennsylvania, specializing in semiconductors and cable television equipment. They formed in New York City in 1923 as an electronics manufacturer. Dur ...
,
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
, Sarnoff, Thomson,
Zenith The zenith (, ) is an imaginary point directly "above" a particular location, on the celestial sphere. "Above" means in the vertical direction ( plumb line) opposite to the gravity direction at that location (nadir). The zenith is the "highes ...
and the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private Land-grant university, land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern t ...
. Field testing of HDTV at 199 sites in the United States was completed August 14, 1994. The first public HDTV broadcast in the United States occurred on July 23, 1996, when the
Raleigh, North Carolina Raleigh (; ) is the capital city of the state of North Carolina and the seat of Wake County in the United States. It is the second-most populous city in North Carolina, after Charlotte. Raleigh is the tenth-most populous city in the South ...
television station WRAL-HD began broadcasting from the existing tower of
WRAL-TV WRAL-TV (channel 5) is a television station licensed to Raleigh, North Carolina, United States, serving as the NBC affiliate for the Research Triangle area. It is the flagship station of the locally based Capitol Broadcasting Company, which h ...
southeast of Raleigh, winning a race to be first with the HD Model Station in Washington, D.C., which began broadcasting July 31, 1996 with the callsign WHD-TV, based out of the facilities of
NBC The National Broadcasting Company (NBC) is an American English-language commercial broadcast television and radio network. The flagship property of the NBC Entertainment division of NBCUniversal, a division of Comcast, its headquarters are ...
owned and operated station
WRC-TV WRC-TV (channel 4) is a television station in Washington, D.C., airing programming from the NBC network. It is owned and operated by the network's NBC Owned Television Stations division alongside Class A Telemundo outlet WZDC-CD (channel 44). ...
. The American
Advanced Television Systems Committee The Advanced Television Systems Committee (ATSC) is an international nonprofit organization developing technical standards for digital terrestrial television and data broadcasting. ATSC's 120-plus member organizations represent the broadcast, b ...
(ATSC) HDTV system had its public launch on October 29, 1998, during the live coverage of astronaut
John Glenn John Herschel Glenn Jr. (July 18, 1921 – December 8, 2016) was an American Marine Corps aviator, engineer, astronaut, businessman, and politician. He was the third American in space, and the first American to orbit the Earth, circlin ...
's return mission to space on board the
Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. I ...
''
Discovery Discovery may refer to: * Discovery (observation), observing or finding something unknown * Discovery (fiction), a character's learning something unknown * Discovery (law), a process in courts of law relating to evidence Discovery, The Discovery ...
''. The signal was transmitted coast-to-coast, and was seen by the public in science centers, and other public theaters specially equipped to receive and display the broadcast.


European HDTV broadcasts

Between 1988 and 1991, several European organizations were working on discrete cosine transform (DCT) based digital video coding standards for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster
RAI RAI – Radiotelevisione italiana (; commercially styled as Rai since 2000; known until 1954 as Radio Audizioni Italiane) is the national public broadcasting company of Italy, owned by the Ministry of Economy and Finance. RAI operates many terr ...
, developed a DCT
video codec A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, ''codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an '' ...
that broadcast near-studio-quality HDTV transmission at about 70140 
Mbit/s In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mult ...
. The first HDTV transmissions in Europe, albeit not direct-to-home, began in 1990, when RAI broadcast the
1990 FIFA World Cup The 1990 FIFA World Cup was the 14th FIFA World Cup, a quadrennial football tournament for men's senior national teams. It was held from 8 June to 8 July 1990 in Italy, the second country to host the event for a second time (the first being Me ...
using several experimental HDTV technologies, including the digital DCT-based EU 256 codec, the mixed analog-digital HD-MAC technology, and the analog
MUSE In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in th ...
technology. The matches were shown in 8 cinemas in Italy, where the tournament was played, and 2 in Spain. The connection with Spain was made via the Olympus satellite link from
Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus ( legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...
to
Barcelona Barcelona ( , , ) is a city on the coast of northeastern Spain. It is the capital and largest city of the autonomous community of Catalonia, as well as the second most populous municipality of Spain. With a population of 1.6 million within c ...
and then with a
fiber optic An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a mean ...
connection from Barcelona to
Madrid Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...
. After some HDTV transmissions in Europe, the standard was abandoned in 1993, to be replaced by a digital format from DVB. The first regular broadcasts started on January 1, 2004, when the Belgian company Euro1080 launched the HD1 channel with the traditional
Vienna New Year's Concert The Vienna New Year's Concert () is an annual concert of classical music performed by the Vienna Philharmonic on the morning of New Year's Day in Vienna, Austria. The concert occurs at the Musikverein at 11:15. The orchestra performs the same c ...
. Test transmissions had been active since the IBC exhibition in September 2003, but the New Year's Day broadcast marked the official launch of the HD1 channel, and the official start of direct-to-home HDTV in Europe. Euro1080, a division of the former and now bankrupt Belgian TV services company Alfacam, broadcast HDTV channels to break the pan-European stalemate of "no HD broadcasts mean no HD TVs bought means no HD broadcasts ..." and kick-start HDTV interest in Europe. The HD1 channel was initially
free-to-air Free-to-air (FTA) services are television (TV) and radio services broadcast in unencrypted form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscript ...
and mainly comprised sporting, dramatic, musical and other cultural events broadcast with a multi-lingual soundtrack on a rolling schedule of 4 or 5 hours per day. These first European HDTV broadcasts used the 1080i format with MPEG-2 compression on a DVB-S signal from SES's Astra 1H satellite. Euro1080 transmissions later changed to MPEG-4/AVC compression on a DVB-S2 signal in line with subsequent broadcast channels in Europe. Despite delays in some countries, the number of European HD channels and viewers has risen steadily since the first HDTV broadcasts, with SES's annual ''Satellite Monitor'' market survey for 2010 reporting more than 200 commercial channels broadcasting in HD from Astra satellites, 185 million HD capable TVs sold in Europe (£60 million in 2010 alone), and 20 million households (27% of all European digital satellite TV homes) watching HD satellite broadcasts (16 million via Astra satellites). In December 2009, the United Kingdom became the first European country to deploy high-definition content using the new
DVB-T2 DVB-T2 is an abbreviation for "Digital Video Broadcasting – Second Generation Terrestrial"; it is the extension of the television standard DVB-T, issued by the consortium DVB, devised for the broadcast transmission of digital terrestrial tele ...
transmission standard, as specified in the Digital TV Group (DTG)
D-book The D-Book is the UK technical specification for digital terrestrial television (DTT). The Digital TV Group (DTG) has published and maintained the D-Book for over a decade and the specification is updated annually to keep up with the pace of de ...
, on digital terrestrial television. The
Freeview HD Freeview is the United Kingdom's sole digital terrestrial television platform. It is operated by Digital UK Ltd and DTV Services Ltd, a joint venture between the BBC, ITV, Channel 4, Channel 5 and Sky. It was launched on 30 October 2002, t ...
service currently contains 13 HD channels () and was rolled out region by region across the UK in accordance with the digital switchover process, finally being completed in October 2012. However, Freeview HD is not the first HDTV service over digital terrestrial television in Europe; Italy's Rai HD channel started broadcasting in 1080i on April 24, 2008, using the
DVB-T DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Feb ...
transmission standard. In October 2008, France deployed five high definition channels using DVB-T transmission standard on digital terrestrial distribution.


Notation

HDTV broadcast systems are identified with three major parameters: * Frame size in pixels is defined as ''number of horizontal pixels × number of vertical pixels'', for example ''1280 × 720'' or ''1920 × 1080''. Often the number of horizontal pixels is implied from context and is omitted, as in the case of ''720p'' and ''1080p''. * Scanning system is identified with the letter ''p'' for
progressive scan Progressive scanning (alternatively referred to as noninterlaced scanning) is a format of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to interlaced video used ...
ning or ''i'' for interlaced scanning. * Frame rate is identified as number of video frames per second. For interlaced systems, the number of frames per second should be specified, but it is not uncommon to see the field rate incorrectly used instead. If all three parameters are used, they are specified in the following form: '' rame sizescanning system] rame or field rate' or '' rame size rame or field ratescanning system]''. Often, frame size or frame rate can be dropped if its value is implied from context. In this case, the remaining numeric parameter is specified first, followed by the scanning system. For example, ''1920×1080p25'' identifies progressive scanning format with 25 frames per second, each frame being 1,920
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the sm ...
s wide and 1,080 pixels high. The ''1080i25'' or ''1080i50'' notation identifies interlaced scanning format with 25 frames (50 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The ''1080i30'' or ''1080i60'' notation identifies interlaced scanning format with 30 frames (60 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The ''720p60'' notation identifies progressive scanning format with 60 frames per second, each frame being 720 pixels high; 1,280 pixels horizontally are implied. Systems using 50 Hz support three scanning rates: 50i, 25p and 50p, while 60 Hz systems support a much wider set of frame rates: 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p and 60p. In the days of standard-definition television, the fractional rates were often rounded up to whole numbers, e.g. 23.976p was often called 24p, or 59.94i was often called 60i. Sixty Hertz high definition television supports both fractional and slightly different integer rates, therefore strict usage of notation is required to avoid ambiguity. Nevertheless, 29.97p/59.94i is almost universally called 60i, likewise 23.976p is called 24p. For the commercial naming of a product, the frame rate is often dropped and is implied from context (e.g., a ''1080i television set''). A frame rate can also be specified without a resolution. For example, 24p means 24 progressive scan frames per second, and 50i means 25 interlaced frames per second. There is no single standard for HDTV color support. Colors are typically broadcast using a (10-bits per channel) YUV color space but, depending on the underlying image generating technologies of the receiver, are then subsequently converted to a
RGB The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additi ...
color space using standardized algorithms. When transmitted directly through the Internet, the colors are typically pre-converted to 8-bit RGB channels for additional storage savings with the assumption that it will only be viewed only on a (
sRGB sRGB is a standard RGB (red, green, blue) color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the World Wide Web. It was subsequently standardized by the International Electrotechnical Commission ( ...
) computer screen. As an added benefit to the original broadcasters, the losses of the pre-conversion essentially make these files unsuitable for professional TV re-broadcasting. Most HDTV systems support resolutions and frame rates defined either in the ATSC table 3, or in EBU specification. The most common are noted below.


Display resolutions

At a minimum, HDTV has twice the linear resolution of
standard-definition television Standard-definition television (SDTV, SD, often shortened to standard definition) is a television system which uses a resolution that is not considered to be either high or enhanced definition. "Standard" refers to it being the prevailing s ...
(SDTV), thus showing greater detail than either analog television or regular DVD. The technical standards for broadcasting HDTV also handle the 16:9 aspect ratio images without using letterboxing or
anamorphic Anamorphic format is the cinematography technique of shooting a widescreen picture on standard 35 mm film or other visual recording media with a non-widescreen native aspect ratio. It also refers to the projection format in which a distorted ...
stretching, thus increasing the effective image resolution. A very high-resolution source may require more bandwidth than available in order to be transmitted without loss of fidelity. The
lossy compression In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...
that is used in all digital HDTV storage and transmission systems will distort the received picture when compared to the uncompressed source.


Standard frame or field rates

ATSC Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that ...
and DVB define the following frame rates for use with the various broadcast standards: * 23.976 Hz (film-looking frame rate compatible with
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
clock speed standards) * 24 Hz (international film and ATSC high-definition material) * 25 Hz (PAL film, DVB standard-definition and high-definition material) * 29.97 Hz (NTSC film and standard-definition material) * 30 Hz (NTSC film, ATSC high-definition material) * 50 Hz (DVB high-definition material) * 59.94 Hz (ATSC high-definition material) * 60 Hz (ATSC high-definition material) The optimum format for a broadcast depends upon the type of videographic recording medium used and the image's characteristics. For best fidelity to the source, the transmitted field ratio, lines, and frame rate should match those of the source. PAL, SECAM and NTSC frame rates technically apply only to analogue standard-definition television, not to digital or high definition broadcasts. However, with the rollout of digital broadcasting, and later HDTV broadcasting, countries retained their heritage systems. HDTV in former PAL and SECAM countries operates at a frame rate of 25/50 Hz, while HDTV in former NTSC countries operates at 30/60 Hz.


Types of media

High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable,
IPTV Internet Protocol television (IPTV) is the delivery of television content over Internet Protocol (IP) networks. This is in contrast to delivery through traditional terrestrial, satellite, and cable television formats. Unlike downloaded medi ...
,
Blu-ray The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of sto ...
video disc (BD), and internet downloads. In the US, residents in the line of sight of television station broadcast antennas can receive free, over-the-air programming with a television set with an
ATSC tuner An ATSC (Advanced Television Systems Committee) tuner, often called an ATSC receiver or HDTV tuner, is a type of television tuner that allows reception of digital television (DTV) television channels that use ATSC standards, as transmitted by ...
via a TV aerial. Laws prohibit homeowners' associations and city government from banning the installation of antennas. Standard 35mm
photographic film Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine t ...
used for cinema projection has a much higher
image resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how cl ...
than HDTV systems, and is exposed and projected at a rate of 24
frames per second A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...
(frame/s). To be shown on standard television, in PAL-system countries, cinema film is scanned at the TV rate of 25 frame/s, causing a speedup of 4.1 percent, which is generally considered acceptable. In NTSC-system countries, the TV scan rate of 30 frame/s would cause a perceptible speedup if the same were attempted, and the necessary correction is performed by a technique called 3:2 pulldown: Over each successive pair of film frames, one is held for three video fields (1/20 of a second) and the next is held for two video fields (1/30 of a second), giving a total time for the two frames of 1/12 of a second and thus achieving the correct average film frame rate. Non-cinematic HDTV video recordings intended for broadcast are typically recorded either in 720p or 1080i format as determined by the broadcaster. 720p is commonly used for Internet distribution of high-definition video, because most computer monitors operate in progressive-scan mode. 720p also imposes less strenuous storage and decoding requirements compared to both 1080i and 1080p. 1080p/24, 1080i/30, 1080i/25, and 720p/30 is most often used on Blu-ray Disc.


Recording and compression

HDTV can be recorded to
D-VHS D-VHS is a digital video recording format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. The "D" in D-VHS originally stood for "Data", but JVC renamed the format as "Digital VHS". Released in 1998, it uses the same p ...
(Digital-VHS or Data-VHS),
W-VHS W-VHS (Wide-VHS) is a HDTV-capable analog recording videocassette format created by JVC. The format was originally introduced in 1994 for use with Japan's Hi-Vision, an early analog high-definition television system. Naming JVC gives four r ...
(analog only), to an HDTV-capable
digital video recorder A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct ...
(for example
DirecTV DirecTV (trademarked as DIRECTV) is an American multichannel video programming distributor based in El Segundo, California. Originally launched on June 17, 1994, its primary service is a digital satellite service serving the United States. ...
's high-definition digital video recorder,
Sky HD Sky HD may refer to: * Sky+ HD, a high-definition television service provided by British Sky Broadcasting Group in the United Kingdom and Ireland *Sky HD (Italy) Sky Italia S.r.l. is an Italian satellite television platform owned by the Americ ...
's
set-top box A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of sign ...
,
Dish Network DISH Network Corporation (DISH, an acronym for DIgital Sky Highway) is an American television provider and the owner of the direct-broadcast satellite provider Dish, commonly known as Dish Network, and the over-the-top IPTV service, Sling TV ...
's VIP 622 or VIP 722 high-definition digital video recorder receivers (these set-top boxes allow for HD on the Primary TV and SD on the secondary TV (TV2) without a secondary box on TV2), or
TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose ...
's Series 3 or HD recorders), or an HDTV-ready HTPC. Some cable boxes are capable of receiving or recording two or more broadcasts at a time in HDTV format, and HDTV programming, some included in the monthly cable service subscription price, some for an additional fee, can be played back with the cable company's on-demand feature. The massive amount of data storage required to archive uncompressed streams meant that inexpensive uncompressed storage options were not available to the consumer. In 2008, the Hauppauge 1212 Personal Video Recorder was introduced. This device accepts HD content through component video inputs and stores the content in MPEG-2 format in a .ts file or in a Blu-ray-compatible format
.m2ts .m2ts is a filename extension used for the Blu-ray disc Audio-Video (BDAV) MPEG-2 Transport Stream (M2TS) container file format. It is used for multiplexing audio, video and other streams. It is based on the MPEG-2 transport stream container.Blu ...
file on the hard drive or DVD burner of a computer connected to the PVR through a USB 2.0 interface. More recent systems are able to record a broadcast high definition program in its 'as broadcast' format or transcode to a format more compatible with Blu-ray. Analog tape recorders with bandwidth capable of recording analog HD signals, such as W-VHS recorders, are no longer produced for the consumer market and are both expensive and scarce in the secondary market. In the United States, as part of the FCC's ''plug and play'' agreement, cable companies are required to provide customers who rent HD set-top boxes with a set-top box with "functional"
FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony ...
(IEEE 1394) on request. None of the
direct broadcast satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna comm ...
providers have offered this feature on any of their supported boxes, but some
cable TV Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadc ...
companies have. , boxes are not included in the FCC mandate. This content is protected by encryption known as 5C. This encryption can prevent duplication of content or simply limit the number of copies permitted, thus effectively denying most if not all
fair use Fair use is a doctrine in United States law that permits limited use of copyrighted material without having to first acquire permission from the copyright holder. Fair use is one of the limitations to copyright intended to balance the interests ...
of the content.


See also

*
Display motion blur Display motion blur, also called ''HDTV blur'' and ''LCD motion blur'', refers to several visual artifacts (anomalies or unintended effects affecting still or moving images) that are frequently found on modern consumer high-definition television se ...
*
Glossary of video terms This glossary defines terms that are used in the documen"Defining Video Quality Requirements: A Guide for Public Safety" developed by thVideo Quality in Public Safety (VQIPS) Working Group It contains terminology and explanations of concepts relev ...
*
High Efficiency Video Coding High Efficiency Video Coding (HEVC), also known as H.265 and MPEG-H Part 2, is a video compression standard designed as part of the MPEG-H project as a successor to the widely used Advanced Video Coding (AVC, H.264, or MPEG-4 Part 10). In compa ...
*
List of digital television deployments by country This is a list of digital television deployments by country, which summarises the process and progress of transition from analogue to digital broadcasting. The transition to digital television is a process that is happening at different paces ...
* Optimum HDTV viewing distance *
Ultra-high-definition television Ultra-high-definition television (also known as Ultra HD television, Ultra HD, UHDTV, UHD and Super Hi-Vision) 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 ...
(UHD or UHDTV)


References


Further reading

* Joel Brinkley (1997), ''Defining Vision: The Battle for the Future of Television'', New York: Harcourt Brace.
High Definition Television: The Creation, Development and Implementation of HDTV Technology
by Philip J. Cianci (McFarland & Company, 2012)
Technology, Television, and Competition
(New York: Cambridge University Press, 2004)


External links

;History

the Italian HDTV experience from 1980s to 2006 in Italian C.R.I.T./RAI
The HDTV Archive Project
;European adoption
Images formats for HDTV
article from the EBU, Technical Review
High Definition for Europe a progressive approach
article from the EBU, Technical Review
High Definition (HD) Image Formats for Television Production
technical report from the EBU {{DEFAULTSORT:High-Definition Television Telecommunications-related introductions in 1936 Telecommunications-related introductions in 1990 ATSC Consumer electronics Digital television Film and video technology History of television Television terminology