View source for Engineering:High-definition television

{{Short description|TV resolution standard}}

'''High-definition television''' ('''HDTV''') describes a [[Engineering:Television|television]] or video system which provides a substantially higher [[Image resolution|image resolution]] than the previous generation of technologies. The term has been used since at least 1933;<ref name=hd1933/> in more recent times, it refers to the generation following [[Engineering:Standard-definition television|standard-definition television]] (SDTV). It is the current de facto standard video format used in most broadcasts: [[Engineering:Terrestrial television|terrestrial broadcast television]], [[Engineering:Cable television|cable television]], [[Engineering:Satellite television|satellite television]].

== Formats ==
HDTV may be transmitted in various formats:
* [[Engineering:720p|720p]] ({{resx|1280×720p}}): 921,600 pixels
* [[Engineering:1080i|1080i]] ({{resx|1920×1080i}}) [[Interlaced video|interlaced]] scan: 1,036,800 pixels (≈1.04{{nbsp}}Mpx).
* [[Engineering:1080p|1080p]] ({{resx|1920×1080p}}) progressive scan: 2,073,600 pixels (≈2.07{{nbsp}}Mpx).
** Some countries also use a non-standard CTA resolution, such as {{resx|1440×1080i}}: 777,600 pixels (≈0.78{{nbsp}}Mpx) per field or 1,555,200 pixels (≈1.56{{nbsp}}Mpx) per frame<!-- Do not delete this, it is used for all free to air HDTV in the UK (and probably elsewhere) and is also used by various home recording equipment. See also the 1080i article. -->

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.<ref>{{cite book|last1=Jones|first1=Graham A.|title=A Broadcast Engineering Tutorial for Non-Engineers|date=2005|publisher=Taylor & Francis|isbn=9781136035210|page=34|url=https://books.google.com/books?id=HfOKIjFODrcC&pg=PT34|access-date=2 August 2017}}</ref> HDTV as is known today first started official broadcasting in 1989 in Japan, under the [[Engineering:Multiple sub-Nyquist sampling encoding|MUSE]]/Hi-Vision analog system.<ref>{{cite web|url=https://www.nhk.or.jp/strl/aboutstrl/evolution-of-tv-en/p19.html|title=The Evolution of TV – A Brief History of TV Technology in Japan|website=www.nhk.or.jp|access-date=2018-05-26|archive-date=2019-08-25|archive-url=https://web.archive.org/web/20190825105008/http://www.nhk.or.jp/strl/aboutstrl/evolution-of-tv-en/p19.html|url-status=dead}}</ref> HDTV was widely adopted worldwide in the late 2000s.<ref>{{cite web|url=https://www.businessinsider.com.au/game-changing-tech-from-the-2000s-2012-8|title=10 Game-Changing Pieces of Tech From The 2000s|first=Kevin|last=Smith|date=3 August 2012|access-date=26 May 2018|archive-date=27 May 2018|archive-url=https://web.archive.org/web/20180527120710/https://www.businessinsider.com.au/game-changing-tech-from-the-2000s-2012-8|url-status=live}}</ref>

== Standards ==
[[Image:Digital broadcast standards.svg|thumb|upright=1.5|Map of [[Engineering:List of digital television deployments by country|digital terrestrial television broadcasting standards by country]]]]
All modern high-definition broadcasts utilize [[Engineering:Digital television|digital television]] standards
The major digital television broadcast standards used for terrestrial, cable, satellite, and mobile devices are:
* [[DVB]], originating in Europe and also used in much of Asia, Africa, and Australia
* ATSC, used in North America
* [[Engineering:Digital Terrestrial Multimedia Broadcast|DTMB]], used in China and some neighboring countries
* [[Company:ISDB|ISDB]], used in two incompatible variations in Japan and South America
* DMB, used by mobile devices in South Korea

These standards use a variety of [[Video codec|video codec]]s, some of which are also used for [[Engineering:Internet video|internet video]].

== History ==
{{Further|Engineering:Analog high-definition television system|Biography:History of television}}

The term ''high definition'' once described a series of television systems first announced in 1933<ref name=hd1933>{{cite journal | date=13 October 1933 | url=https://www.newspapers.com/article/evening-despatch-bbc-television-tests-t/132104380/ | title=BBC Television: Tests Through Ultra Short-Wave Transmitter | journal=Evening Despatch | location=Birmingham | page=9 | via=Newspapers.com}}</ref> and launched starting in August 1936;<ref>{{cite web|title=BBC- History of the BBC- First regular hi-definition television service|url=https://www.bbc.com/historyofthebbc/anniversaries/november/first-regular-television-service/|date=1936-11-02|access-date=2023-04-04|archive-date=2023-04-05|archive-url=https://web.archive.org/web/20230405192741/https://www.bbc.com/historyofthebbc/anniversaries/november/first-regular-television-service/|url-status=live}}</ref> however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30<!-- Baird's 1926 broadcasts consisted of 30 vertical (actually curved) lines. --> 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 early 21st century, this race has continued with [[4K resolution|4K]], [[5K resolution|5K]] and [[8K resolution|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 [[Engineering:405-line television system|405 line]] interlaced systems. The Baird system was discontinued in February 1937.<ref name="since1936">{{cite web |url=http://www.teletronic.co.uk/tvera.htm |title=Teletronic – The Television History Site |publisher=Teletronic.co.uk |access-date=2011-08-30 |archive-date=2011-08-13 |archive-url=https://web.archive.org/web/20110813233820/http://www.teletronic.co.uk/tvera.htm |url-status=live }}</ref> In 1938 France followed with its own [[Engineering:441-line television system|441-line]] system, variants of which were also used by a number of other countries. The US [[Engineering:NTSC|NTSC]] 525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at [[Engineering:819 line|819 line]]s, a system that should have been high definition even by today's{{when|date=October 2023}} 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 [[Interlaced video|interlacing]] and a 4:3 [[Aspect ratio (image)|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&nbsp;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&nbsp;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 [[Engineering:PAL|PAL]] and [[Engineering:SECAM|SECAM]] 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 (1.67:1) aspect ratio and 60&nbsp;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&nbsp;Hz
* NHK color: 5:3 aspect ratio, 1125 lines, 60&nbsp;Hz
* NHK monochrome: 4:3 aspect ratio, 2125 lines, 50&nbsp;Hz
* BBC colour: 8:3 aspect ratio, 1501 lines, 60&nbsp;Hz<ref>{{cite book|last=Cianci|first=Philip J.|title=High Definition Television|year=2012|publisher=McFarland|location=NC, US|isbn=978-0-7864-4975-0|pages=1–25|url=https://mcfarlandbooks.com/product/high-definition-television/|access-date=2018-12-12|archive-date=2018-12-15|archive-url=https://web.archive.org/web/20181215223627/https://mcfarlandbooks.com/product/high-definition-television/|url-status=live}}</ref>

Since the formal adoption of [[DVB|digital video broadcasting]]'s (DVB) widescreen HDTV transmission modes in the mid to late 2000s; the 525-line [[Engineering:NTSC|NTSC]] (and [[PAL-M]]) systems, as well as the European 625-line [[Engineering:PAL|PAL]] and [[Engineering:SECAM|SECAM]] systems, are now regarded as ''standard definition'' television systems.

=== Analog systems ===
{{Main|Engineering:Analog high-definition television system}}

Early HDTV broadcasting used [[Engineering:Analog television|analog]] technology, but today it is transmitted [[Engineering:Digital television|digitally]] and uses [[Data compression#Video|video 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 [[Place:Soviet Union|Soviet Union]] developed ''Тransformator'' ({{lang-ru|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.<ref>{{cite web|author=Валерий Хлебородов|url=http://rus.625-net.ru/625/2007/01/tvch.htm|title=HDTV in the Russian Federation: problems and prospects of implementation (in Russian)|publisher=Rus.625-net.ru|access-date=2013-03-11|url-status=dead|archive-url=https://web.archive.org/web/20130727143639/http://rus.625-net.ru/625/2007/01/tvch.htm|archive-date=2013-07-27}}</ref>

In 1986, the European Community proposed [[Engineering:HD-MAC|HD-MAC]], an analog HDTV system with 1,152 lines. A public demonstration took place for the 1992 Summer Olympics in Barcelona. However HD-MAC was scrapped in 1993 and the [[DVB|Digital Video Broadcasting]] (DVB) project was formed, which would foresee development of a digital HDTV standard.<ref>{{cite book|url=https://books.google.com/books?id=xL_Rq6qUvT0C&q=%22hd-mac%22+dvb&pg=PA4|title=DVB: The Family of International Standards for Digital Video Broadcasting|first=Ulrich|last=Reimers|date=11 August 2018|publisher=Springer Science & Business Media|via=Google Books|isbn=9783540435457}}</ref>

==== Japan ====
In 1979, the Japanese public broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio.<ref>{{cite web|url=http://www.pcworld.com/article/id,132289-c,hdtv/article.html|title=Researchers Craft HDTV's Successor|date=2007-05-28|access-date=2007-05-29|archive-date=2008-04-30|archive-url=https://web.archive.org/web/20080430214045/http://www.pcworld.com/article/id,132289-c,hdtv/article.html|url-status=dead}}</ref> The system, known as Hi-Vision or MUSE after its [[Engineering:Multiple sub-Nyquist sampling encoding|multiple sub-Nyquist sampling encoding]] (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.<ref>{{cite web|url=http://www.tech-notes.tv/Archive/tech_notes_002.htm|title=Digital TV Tech Notes, Issue #2|access-date=2008-01-17|archive-date=2008-01-21|archive-url=https://web.archive.org/web/20080121192353/http://www.tech-notes.tv/Archive/tech_notes_002.htm|url-status=live}}</ref> 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.<ref>James Sudalnik and Victoria Kuhl, "High definition television"</ref> NHK taped the 1984 Summer Olympics with a Hi-Vision camera, weighing 40&nbsp;kg.<ref name="auto">{{cite web|url=https://www.nhk.or.jp/digitalmuseum/nhk50years_en/history/p26/index.html|title=50 Years of NHK Television|first=50 Years of NHK|last=Television|website=www.nhk.or.jp|access-date=2018-05-26|archive-date=2018-09-15|archive-url=https://web.archive.org/web/20180915040059/http://www.nhk.or.jp/digitalmuseum/nhk50years_en/history/p26/index.html|url-status=live}}</ref>

Satellite test broadcasts started June 4, 1989, the first daily high-definition programs in the world,<ref>{{cite news|url=https://www.nytimes.com/1989/06/04/world/japan-begins-broadcasts-of-high-definition-tv.html|title=Japan Begins Broadcasts of High-Definition TV|first=David E. Sanger and Special To the New York|last=Times|newspaper=The New York Times|date=1989-06-04|access-date=2018-05-26|archive-date=2018-05-27|archive-url=https://web.archive.org/web/20180527030921/https://www.nytimes.com/1989/06/04/world/japan-begins-broadcasts-of-high-definition-tv.html|url-status=live}}</ref> with regular testing starting on November 25, 1991, or "Hi-Vision Day"{{snd}}dated exactly to refer to its 1,125-lines resolution.<ref>{{cite news|url=https://www.nytimes.com/1991/11/26/business/few-see-japan-make-tv-history.html|title=Few See Japan Make TV History|first=David E.|last=Sanger|newspaper=The New York Times|date=1991-11-26|access-date=2018-05-26|archive-date=2018-05-27|archive-url=https://web.archive.org/web/20180527023835/https://www.nytimes.com/1991/11/26/business/few-see-japan-make-tv-history.html|url-status=live}}</ref> 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 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.<ref>{{Cite web|last=Pauchon|first=B|title=Analogue HDTV in Europe|url=https://tech.ebu.ch/docs/techreview/trev_253-analogue.pdf}}</ref><ref>{{Cite web|last=Farrell|first=Joseph|title=Standard Setting in High-Definition Television|url=http://faculty.haas.berkeley.edu/shapiro/hdtv.pdf|access-date=2020-09-02|archive-date=2021-04-14|archive-url=https://web.archive.org/web/20210414225240/http://faculty.haas.berkeley.edu/shapiro/hdtv.pdf|url-status=live}}</ref>

In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV ([[Engineering:Sony HDVS|Sony HDVS]]). Japan remained the only country with successful public broadcasting of analog HDTV, with seven broadcasters sharing a single channel.{{Citation needed|date=August 2020}}

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.<ref>{{cite web|url=https://www.newscientist.com/article/mg14119153-000-technology-while-japan-admits-that-analogue-tv-is-a-dead-end/|title=Technology: . . . while Japan admits that analogue TV is a dead end|access-date=2018-05-26|archive-date=2018-05-27|archive-url=https://web.archive.org/web/20180527023510/https://www.newscientist.com/article/mg14119153-000-technology-while-japan-admits-that-analogue-tv-is-a-dead-end/|url-status=live}}</ref> A Hi-Vision [[Engineering:Videocassette recorder|VCR]] from [[Company:NEC|NEC]] 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.<ref>{{cite book|url=https://books.google.com/books?id=0mbsfr38GTgC&q=hi+vision+day+1991&pg=PA108|title=High Definition Television: The Creation, Development and Implementation of HDTV Technology|first=Philip J.|last=Cianci|date=10 January 2013|publisher=McFarland|via=Google Books|isbn=9780786487974}}</ref> 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.<ref>{{cite news|url=https://www.nytimes.com/1992/07/04/business/technology-shift-blurs-future-of-japan-s-new-tv-system.html|title=Technology Shift Blurs Future of Japan's New TV System|first=Andrew|last=Pollack|newspaper=The New York Times|date=1992-07-04|access-date=2018-05-26|archive-date=2018-05-27|archive-url=https://web.archive.org/web/20180527023733/https://www.nytimes.com/1992/07/04/business/technology-shift-blurs-future-of-japan-s-new-tv-system.html|url-status=live}}</ref> By mid-1993 prices of receivers were still as high as 1.5 million [[Finance:Japanese yen|yen]] (US$15,000).<ref>{{cite book|url=https://books.google.com/books?id=R4j_Pmj_l9MC&q=%22hi-vision%22+receivers+japan+%22yen%22&pg=PA198|title=Technology, Television, and Competition: The Politics of Digital TV|first=Jeffrey A.|last=Hart|date=5 February 2004|publisher=Cambridge University Press|via=Google Books|isbn=9781139442244}}</ref>

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.<ref>{{cite web|url=http://articles.latimes.com/1994-02-23/business/fi-26252_1_world-standard|title=Japan Gives Up on Analog-Based HDTV System : Technology: Government says U.S.-backed digital format is likely to become a world standard.|first=JUBE Jr.|last=SHIVER|date=23 February 1994|via=LA Times}}</ref> 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.<ref>{{cite web|url=https://variety.com/1994/tv/news/japanese-revive-hdtv-system-118589/|title=Japanese revive HDTV system|work=Variety|date=24 February 1994|access-date=19 June 2018|archive-date=9 July 2018|archive-url=https://web.archive.org/web/20180709094444/https://variety.com/1994/tv/news/japanese-revive-hdtv-system-118589/|url-status=live}}</ref> That year NHK started development of [[Engineering:Digital television|digital television]] in an attempt to catch back up to America and Europe. This resulted in the [[Company:ISDB|ISDB]] format.<ref>{{cite book|url=https://books.google.com/books?id=8Jl6VPARb9MC&q=japan+digital+hdtv&pg=PA247|title=Digital Television Standardization and Strategies|first=Katharina|last=Grimme|date=11 August 2018|publisher=Artech House|via=Google Books|isbn=9781580532976}}</ref> Japan started digital satellite and HDTV broadcasting in December 2000.<ref name="auto"/>

=== Rise of digital compression ===
High-definition digital television was not possible with [[Uncompressed video|uncompressed video]], which requires a [[Bandwidth (computing)|bandwidth]] exceeding 1{{nbsp}}[[Data-rate units#Gigabit per second|Gbit/s]] for studio-quality HD [[Engineering:Digital video|digital video]].<ref name="Barbero">{{cite journal |last1=Barbero |first1=M. |last2=Hofmann |first2=H. |last3=Wells |first3=N. D. |title=DCT source coding and current implementations for HDTV |journal=EBU Technical Review |date=14 November 1991 |issue=251 |pages=22–33 |publisher=European Broadcasting Union |url=https://tech.ebu.ch/publications/trev_251-barbero |access-date=4 November 2019 |archive-date=4 November 2019 |archive-url=https://web.archive.org/web/20191104171502/https://tech.ebu.ch/publications/trev_251-barbero |url-status=live }}</ref><ref>{{cite book |last1=Lee |first1=Jack |title=Scalable Continuous Media Streaming Systems: Architecture, Design, Analysis and Implementation |date=2005 |publisher={{wipe|John Wiley & Sons}} |isbn=9780470857649 |page=25 |url=https://books.google.com/books?id=7fuvu52cyNEC&pg=PA25}}</ref> Digital HDTV was made possible by the development of [[Discrete cosine transform|discrete cosine transform]] (DCT) [[Data compression#Video|video compression]].<ref name="Shishikui">{{cite book |last1=Shishikui |first1=Yoshiaki |last2=Nakanishi |first2=Hiroshi |last3=Imaizumi |first3=Hiroyuki |title=Signal Processing of HDTV |chapter=An HDTV Coding Scheme using Adaptive-Dimension DCT |date=October 26–28, 1993 |pages=611–618 |doi=10.1016/B978-0-444-81844-7.50072-3 |chapter-url=https://books.google.com/books?id=j9XSBQAAQBAJ&pg=PA611 |publisher=[[Company:Elsevier|Elsevier]] |isbn=9781483298511}}</ref><ref name="Barbero"/> DCT coding is a [[Lossy compression|lossy]] image compression technique that was first proposed by [[Biography:Nasir Ahmed (engineer)|Nasir Ahmed]] in 1972,<ref name="Ahmed">{{cite journal |last=Ahmed |first=Nasir |title=How I Came Up With the Discrete Cosine Transform |journal=Digital Signal Processing |date=January 1991 |volume=1 |issue=1 |pages=4–5 |doi=10.1016/1051-2004(91)90086-Z |url=https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |access-date=2019-10-13 |archive-date=2016-06-10 |archive-url=https://web.archive.org/web/20160610013109/https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |url-status=live }}</ref> and was later adapted into a [[Motion compensation|motion-compensated]] DCT algorithm for [[Video coding format#Video coding standards|video coding standards]] such as the H.26x formats from 1988 onwards and the [[Moving Picture Experts Group|MPEG]] formats from 1993 onwards.<ref name="Ghanbari">{{cite book |last1=Ghanbari |first1=Mohammed |title=Standard Codecs: Image Compression to Advanced Video Coding |date=2003 |publisher=[[Organization:Institution of Engineering and Technology|Institution of Engineering and Technology]] |isbn=9780852967102 |pages=1–2 |url=https://books.google.com/books?id=7XuU8T3ooOAC&pg=PA1}}</ref><ref name="Li">{{cite book |last1=Li |first1=Jian Ping |title=Proceedings of the International Computer Conference 2006 on Wavelet Active Media Technology and Information Processing: Chongqing, China, 29-31 August 2006 |date=2006 |publisher=[[Company:World Scientific|World Scientific]] |isbn=9789812709998 |page=847 |url=https://books.google.com/books?id=FZiK3zXdK7sC&pg=PA847}}</ref> Motion-compensated DCT compression significantly reduces the amount of bandwidth required for a digital TV signal.<ref name="Barbero"/><ref name="Lea">{{cite book |last1=Lea |first1=William |title=Video on demand: Research Paper 94/68 |date=1994 |publisher=House of Commons Library |url=https://researchbriefings.parliament.uk/ResearchBriefing/Summary/RP94-68 |access-date=20 September 2019 |archive-url=https://web.archive.org/web/20190920082623/https://researchbriefings.parliament.uk/ResearchBriefing/Summary/RP94-68 |archive-date=20 September 2019 |url-status=dead }}</ref> By 1991, it had achieved [[Data compression ratio|data compression ratio]]s from 8:1 to 14:1 for near-studio-quality HDTV transmission, down to 70{{ndash}}140&nbsp;[[Data-rate units#Megabit per second|Mbit/s]].<ref name="Barbero"/> Between 1988 and 1991, DCT video compression was widely adopted as the [[Video coding format|video coding standard]] for HDTV implementations, enabling the development of practical digital HDTV.<ref name="Barbero"/><ref name="Shishikui"/><ref name="Cianci">{{cite book |last1=Cianci |first1=Philip J. |title=High Definition Television: The Creation, Development and Implementation of HDTV Technology |date=2014 |publisher=McFarland |isbn=9780786487974 |page=63 |url=https://books.google.com/books?id=0mbsfr38GTgC&pg=PA63}}</ref> Dynamic [[Random-access memory|random-access memory]] ([[Dynamic random-access memory|DRAM]]) was also adopted as [[Framebuffer|framebuffer]] semiconductor memory, with the DRAM [[Engineering:Semiconductor industry|semiconductor industry]]'s increased manufacturing and reducing prices important to the commercialization of HDTV.<ref name="Cianci"/>

Since 1972, [[Organization:International Telecommunication Union|International Telecommunication Union]]'s radio telecommunications sector ([[Organization:ITU-R|ITU-R]]) 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]] in 1993 led to the acceptance of recommendations [[Rec. 709|ITU-R BT.709]].<ref>{{cite web|author=brweb |url=http://www.itu.int/ITU-R/index.asp?category=information&link=hdtv-25&lang=en |title=High definition television comes of age thanks to ITU |publisher=Itu.int |date=2010-06-17 |access-date=2013-03-11}}</ref> 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.<ref>{{cite web |author=Webfactory www.webfactory.ie |url=http://www.dvb.org/about_dvb/history/ |title=History of the DVB Project |publisher=Dvb.org |access-date=2013-03-11 |archive-date=2009-12-18 |archive-url=https://web.archive.org/web/20091218004029/http://www.dvb.org/about_dvb/history/ |url-status=live }}</ref>

DVB created first the standard for [[Astronomy:DVB-S|DVB-S]] digital satellite TV, [[Engineering:DVB-C|DVB-C]] digital cable TV and [[DVB-T]] digital terrestrial TV. These broadcasting systems can be used for both SDTV and HDTV. In the US the [[Engineering:Grand Alliance (HDTV)|Grand Alliance]] proposed [[ATSC standards|ATSC]] as the new standard for SDTV and HDTV. Both ATSC and DVB were based on the [[MPEG-2]] standard, although DVB systems may also be used to transmit video using the newer and more efficient [[Advanced Video Coding|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.{{Citation needed|date=August 2020}}

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&nbsp;Hz and 30/60&nbsp;Hz, largely due to the differences in [[Physics:Mains electricity|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 [[Physics:Motion estimation|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.{{Citation needed|date=August 2020}}

Initially the existing 5:3 aspect ratio had been the main candidate but, due to the influence of widescreen cinema, the aspect ratio [[Engineering:16:9 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 [[Physics:Colorimetry|colorimetry]], and the scan modes [[Engineering:1080i|1080i]] (1,080 actively [[Interlaced video|interlaced]] lines of resolution) and [[Engineering:1080p|1080p]] (1,080 [[Engineering:Progressive scan|progressively scanned]] lines). The British Freeview HD trials used MBAFF, which contains both progressive and interlaced content in the same encoding.{{Citation needed|date=August 2020}}

It also includes the alternative 1440×1152 [[Engineering:HD-MAC|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,<ref>{{cite web |author=Jim Mendrala |url=http://www.tech-notes.tv/Archive/tech_notes_041.htm |title=Digital TV Tech Notes, Issue #41 |publisher=Tech-notes.tv |date=1999-09-27 |access-date=2013-03-11 |archive-date=2013-07-27 |archive-url=https://web.archive.org/web/20130727180634/http://www.tech-notes.tv/Archive/tech_notes_041.htm |url-status=live }}</ref> 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 standards.){{Citation needed|date=August 2020}}

==== Inaugural HDTV broadcast in the United States of America ====
HDTV technology was introduced in the United States in the early 1990s and made official in 1993 by the [[Engineering:Grand Alliance (HDTV)|Digital HDTV Grand Alliance]], a group of television, electronic equipment, communications companies consisting of AT&T Bell Labs, [[Company:General Instrument|General Instrument]], [[Company:Philips|Philips]], [[Company:Sarnoff Corporation|Sarnoff]], [[Company:Vantiva|Thomson]], Zenith and the [[Organization:Massachusetts Institute of Technology|Massachusetts Institute of Technology]]. Field testing of HDTV at 199 sites in the United States was completed August 14, 1994.<ref>{{cite web |url=http://www.allbusiness.com/electronics/consumer-household-electronics-high/7686036-1.html |title=HDTV field testing wraps up |publisher=Allbusiness.com |access-date=2010-10-02 |archive-date=2009-05-21 |archive-url=https://web.archive.org/web/20090521102947/http://www.allbusiness.com/electronics/consumer-household-electronics-high/7686036-1.html |url-status=live }}</ref> The first public HDTV broadcast in the United States occurred on July 23, 1996, when the Raleigh, North Carolina television station WRAL-HD began broadcasting from the existing tower of WRAL-TV southeast of Raleigh, winning a race to be first with the HD Model Station in [[Place:Washington, D.C.|Washington, D.C.]], which began broadcasting July 31, 1996 with the callsign WHD-TV, based out of the facilities of NBC owned and operated station WRC-TV.<ref>{{cite web|url=http://www.wral.com/wral-tv/story/1069461/ |title=History of WRAL Digital |publisher=Wral.com |date=2006-11-22 |access-date=2010-10-02}}</ref><ref>{{cite web|url=http://www.allbusiness.com/electronics/consumer-household-electronics-high/7691754-1.html |title=WRAL-HD begins broadcasting HDTV |publisher=Allbusiness.com |access-date=2010-10-02}}</ref><ref>{{cite web|url=http://www.allbusiness.com/electronics/computer-electronics-manufacturing/7691367-1.html |title=Comark transmitter first in at Model Station |publisher=Allbusiness.com |access-date=2010-10-02}}</ref> The American Advanced Television Systems Committee (ATSC) HDTV system had its public launch on October 29, 1998, during the live coverage of astronaut [[Biography:John Glenn|John Glenn]]'s return mission to space on board the [[Engineering:Space Shuttle|Space Shuttle]] ''[[Engineering:Space Shuttle Discovery|Discovery]]''.<ref name = "bnet1">{{cite news
 | last = Albiniak
 | first = Paige
 | title = HDTV: Launched and Counting.
 | work = Broadcasting and cable
 | publisher = BNET
 | date = 1998-11-02
 | url = http://www.highbeam.com/doc/1G1-53190401.html
 | archive-url = https://web.archive.org/web/20140924040947/http://www.highbeam.com/doc/1G1-53190401.html
 | url-status = dead
 | archive-date = 2014-09-24
 | access-date = 2008-10-24}}
</ref> 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.<ref name = "bnet1"/><ref>{{cite web
 | title = Space Shuttle Discovery: John Glenn Launch
 | website = Internet Movie Database
 | year = 1998
 | url = https://www.imdb.com/title/tt0384554/
 | access-date = 2008-10-25}}</ref>

==== European HDTV broadcasts ====
Between 1988 and 1991, several European organizations were working on [[Discrete cosine transform|discrete cosine transform]] (DCT) based digital [[Video coding format|video coding standards]] for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster RAI, developed a DCT [[Video codec|video codec]] that broadcast near-studio-quality HDTV transmission at about 70{{ndash}}140&nbsp;Mbit/s.<ref name="Barbero"/><ref>{{cite journal |last1=Barbero |first1=M. |last2=Stroppiana |first2=M. |title=Data compression for HDTV transmission and distribution |journal=IEE Colloquium on Applications of Video Compression in Broadcasting |date=October 1992 |pages=10/1–10/5 |url=https://ieeexplore.ieee.org/document/193745}}</ref> The first HDTV transmissions in Europe, albeit not direct-to-home, began in 1990, when RAI broadcast the 1990 FIFA World Cup using several experimental HDTV technologies, including the digital DCT-based EU 256 codec,<ref name="Barbero"/> the mixed analog-digital [[Engineering:HD-MAC|HD-MAC]] technology, and the analog [[Engineering:Multiple sub-Nyquist sampling encoding|MUSE]] 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 [[Place:Rome|Rome]] to [[Place:Barcelona|Barcelona]] and then with a [[Engineering:Optical fiber|fiber optic]] connection from Barcelona to [[Place:Madrid|Madrid]].<ref>{{Cite web|url=http://www.crit.rai.it/eletel/LeMiniSerie/MS3a.pdf|title=ItaLia '90{{snd}} il primo passo della HDTV digitale{{snd}} I parte|trans-title=Le Mini Serie{{snd}} Italia '90{{snd}} The First Step of Digital HDTV{{snd}} part I|archive-url=https://web.archive.org/web/20120619125440/http://www.crit.rai.it/eletel/LeMiniSerie/MS3a.pdf|archive-date=2012-06-19|url-status=dead}}</ref><ref>{{Cite web|url=http://www.crit.rai.it/eletel/LeMiniSerie/MS3b.pdf|title=ItaLia '90{{snd}} il primo passo della HDTV digitale{{snd}} II parte|trans-title=Le Mini Serie{{snd}} Italia '90{{snd}} The First Step of Digital HDTV{{snd}} part II|archive-url=https://web.archive.org/web/20120619125248/http://www.crit.rai.it/eletel/LeMiniSerie/MS3b.pdf|archive-date=2012-06-19|url-status=dead}}</ref> After some HDTV transmissions in Europe, the standard was abandoned in 1993, to be replaced by a digital format from [[Digital Video Broadcasting|DVB]].<ref>{{Cite book|last=Cianci|first=Philip J.|url=https://books.google.com/books?id=0mbsfr38GTgC&q=After+some+HDTV+transmissions+in+Europe,+the+standard+was+abandoned+in+1993,+to+be+replaced+by+a+digital+format+from+DVB&pg=PA142|title=High Definition Television: The Creation, Development and Implementation of HDTV Technology|date=2014-01-10|publisher=McFarland|isbn=978-0-7864-8797-4|language=en}}</ref>

The first regular broadcasts started on January 1, 2004, when the Belgian company [[Engineering:Euro1080|Euro1080]] launched the HD1 channel with the traditional Vienna New Year's Concert. 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.<ref>{{cite press release |publisher=SES ASTRA |date=October 23, 2003 |url=http://www.ses.com/4233325/news/2003/4438389|title=SES ASTRA and Euro1080 to pioneer HDTV in Europe |access-date = January 26, 2012}}</ref>

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.<ref>Bains, Geoff. "Take The High Road" ''What Video & Widescreen TV'' (April, 2004) 22–24</ref> The HD1 channel was initially [[Engineering:Free-to-air|free-to-air]] 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.{{Citation needed|date=August 2020}}

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.{{Citation needed|date=August 2020}}

Despite delays in some countries,<ref>{{cite web|url=http://www.diw.de/documents/publikationen/73/diw_01.c.360950.de/diw_wr_2010-28.pdf |title=Weekly Report No.28/2010, Volume 6 |publisher=German Institute for Economic Research |date=2010-09-08 |access-date=2017-05-19 |url-status=live |archive-url=https://web.archive.org/web/20110408202146/http://www.diw.de/documents/publikationen/73/diw_01.c.360950.de/diw_wr_2010-28.pdf |archive-date=2011-04-08 }}</ref> 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).<ref>{{cite web |url=http://www.ses-astra.com/business/en/support/market-research/index.php |title=Satellite Monitor research |access-date=2011-04-28 |url-status=dead |archive-url=https://web.archive.org/web/20110809042534/http://www.ses-astra.com/business/en/support/market-research/index.php |archive-date=2011-08-09 }}</ref>

In December 2009, the United Kingdom became the first European country to deploy high-definition content using the new [[Engineering:DVB-T2|DVB-T2]] transmission standard, as specified in the Digital TV Group (DTG) [[Engineering:D-book|D-book]], on digital terrestrial television.{{Citation needed|date=August 2020}}

The Freeview HD service currently contains 13 HD channels ({{As of|2016|April|lc=1}}) and was rolled out region by region across the UK in accordance with the [[Engineering:Digital television transition|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 started broadcasting in 1080i on April 24, 2008, using the [[DVB-T]] transmission standard.{{Citation needed|date=August 2020}}

In October 2008, France deployed five high definition channels using DVB-T transmission standard on digital terrestrial distribution.{{Citation needed|date=August 2020}}

== 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&nbsp;×&nbsp;720'' or ''1920&nbsp;×&nbsp;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 [[Engineering:Progressive scan|progressive scan]]ning or '''''i''''' for [[Interlaced video|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: ''[frame size][scanning system][frame or field rate]'' or ''[frame size]/[frame or field rate][scanning system]''.<ref>{{cite web|title=How to Buy a TV|url=https://socialbilitty.com/2016/05/how-to-buy-a-tv/|date=May 11, 2016|publisher=Socialbilitty|access-date=June 22, 2017}}</ref> 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.{{Citation needed|date=August 2020}}

For example, ''1920×1080p25'' identifies progressive scanning format with 25 frames per second, each frame being 1,920 [[Pixel|pixel]]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.{{Citation needed|date=August 2020}}

Systems using 50&nbsp;Hz support three scanning rates: 50i, 25p and 50p, while 60&nbsp;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.{{Citation needed|date=August 2020}}

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.<ref>{{cite web |url=http://www.arridigital.com/creative/camerabasics/7 |title=Scanning Methods (p, i, PsF) |publisher=ARRI Digital |access-date=2011-08-30}}</ref>

There is no single standard for HDTV color support. Colors are typically broadcast using a (10-bits per channel) [[Y′UV|YUV]] color space but, depending on the underlying image generating technologies of the receiver, are then subsequently converted to a [[RGB color model|RGB]] 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]]) 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.{{Citation needed|date=August 2020}}

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.{{Citation needed|date=August 2020}}

=== Display resolutions ===
{| class="wikitable" style="width: 100%;"
|- align=left
! style="width:5%;" rowspan=2| Video format supported [image resolution]
! style="width:10%;" rowspan=2| Native resolution [inherent resolution] (W×H)
! style="width:10%;" colspan=2| Pixels
! colspan=2 | Aspect ratio (W:H)
! rowspan=2 | Description
|-
! Actual
! Advertised (Megapixels)
! [[Aspect ratio (image)|Image]]
! [[Pixel aspect ratio|Pixel]]
|-
| rowspan=3 | 720p<br />(HD ready)<br />1280×720
| {{resx|1024×768}}<br />[[Graphics display resolution#Extended Graphics Array|XGA]]
| 786,432
| 0.8
| 4:3 (1.33:1)
| 1:1 (1.00:1)
| Typically a PC resolution ([[Graphics display resolution#Extended Graphics Array|XGA]]); also a native resolution on many entry-level plasma displays with non-square pixels.
|-
| {{resx|1280×720}}<br />
| 921,600
| 0.9
| 16:9 (1.78:1)
| 1:1
| Standard HDTV resolution and a typical PC resolution ([[Graphics display resolution#WXGA 1366 x 768 and similar (WXGA)|WXGA]]), frequently used by high-end [[Engineering:Video projector|video projectors]]; also used for 750-line video, as defined in SMPTE 296M, ATSC A/53, ITU-R BT.1543.
|-
| {{resx|1366×768}}<br />[[Graphics display resolution#WXGA 1366 x 768 and similar (WXGA)|WXGA]]
| 1,049,088
| 1.0
| 683:384<br />(approx. 16:9)
| 1:1
| A typical PC resolution ([[Graphics display resolution#WXGA 1366 x 768 and similar (WXGA)|WXGA]]); also used by many [[Engineering:HD ready|HD ready]] TV displays based on [[Engineering:Liquid-crystal display|LCD]] technology.
|-
| 1080p/1080i<br />(Full HD)<br />1920×1080
| {{resx|1920×1080}}<br />
| 2,073,600
| 2.1
| 16:9
| 1:1
| Standard HDTV resolution, used by [[Engineering:1080p|full HD]] and [[Engineering:HD ready|HD ready]] 1080p TV displays such as high-end LCD, plasma and [[Engineering:Rear-projection television|rear projection]] TVs, and a typical PC resolution (lower than [[Graphics display resolution#WUXGA (1920×1200)|WUXGA]]); also used for 1125-line video, as defined in SMPTE 274M, ATSC A/53, ITU-R BT.709;
|}

{| class="wikitable" style="width: 100%;"
|- align=left
! style="width:5%;" rowspan=2| Video format supported
! style="width:10%;" rowspan=2| Screen resolution (W×H)
! style="width:10%;" colspan=2| Pixels
! colspan=2| Aspect ratio (W:H)
! rowspan=2| Description
|-
! Actual
! Advertised (Megapixels)
! Image
! Pixel
|-
| 720p<br />(HD Ready)<br />1280×720
| {{resx|1248×702}}<br />Clean Aperture
| 876,096
| 0.9
| 16:9
| 1:1
| Used for 750-line video with faster artifact/overscan compensation, as defined in SMPTE 296M.
|-
| 1080i<br />(Full HD)<br />1920×1080
| {{resx|1440×1080}}<br />[[Engineering:HDCAM|HDCAM]]/[[Engineering:HDV|HDV]]
| 1,555,200
| 1.6
| 16:9
| 4:3
| Used for anamorphic 1125-line video in the HDCAM and HDV formats introduced by [[Company:Sony|Sony]] and defined (also as a luminance subsampling matrix) in [[Engineering:HDCAM|SMPTE D11]].
|-
| 1080p<br />(Full HD)<br />1920×1080
| {{resx|1888×1062}}<br />Clean aperture
| 2,005,056
| 2.0
| 16:9
| 1:1
| Used for 1124-line video with faster artifact/overscan compensation, as defined in SMPTE 274M.
|}

At a minimum, HDTV has twice the linear resolution of [[Engineering:Standard-definition television|standard-definition television]] (SDTV), thus showing greater detail than either analog television or regular [[Engineering:DVD|DVD]]. The technical standards for broadcasting HDTV also handle the 16:9 [[Aspect ratio (image)|aspect ratio]] images without using [[Engineering:Letterboxing (filming)|letterboxing]] or [[Engineering:Anamorphic format|anamorphic]] 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|lossy compression]] 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 standards|ATSC]] and DVB define the following frame rates for use with the various broadcast standards:<ref>{{Citation |url=http://www.microsoft.com/windows/windowsmedia/howto/articles/understandinghdformats.aspx |title=Understanding HD Formats |author=Ben Waggoner |publisher=[[Company:Microsoft|Microsoft]] |year=2007 |access-date=2011-12-09}}</ref><ref name="DVBFramerates">{{cite web|url=http://www.etsi.org/deliver/etsi_ts/101100_101199/101154/01.11.01_60/ts_101154v011101p.pdf#page=19 |title=Digital Video Broadcasting (DVB); Specification for the use of Video and Audio Coding in Broadcasting Applications based on the MPEG-2 Transport Stream |publisher=ETSI |date=2012 |access-date=2017-05-19}}</ref>

* 23.976&nbsp;Hz (film-looking frame rate compatible with [[Engineering:NTSC|NTSC]] clock speed standards)
* 24&nbsp;Hz (international film and ATSC high-definition material)
* 25&nbsp;Hz (PAL film, DVB standard-definition and high-definition material)
* 29.97&nbsp;Hz (NTSC film and standard-definition material)
* 30&nbsp;Hz (NTSC film, ATSC high-definition material)
* 50&nbsp;Hz (DVB high-definition material)
* 59.94&nbsp;Hz (ATSC high-definition material)
* 60&nbsp;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&nbsp;Hz, while HDTV in former NTSC countries operates at 30/60&nbsp;Hz.<ref>{{Citation |title=Why NTSC and PAL Still Matter With HDTV |url=http://hometheater.about.com/od/televisionbasics/qt/ntscpalframes.htm |author=Robert Silva |publisher=About.com |access-date=2011-12-09 }}{{Dead link|date=June 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

=== Types of media ===
High-definition image sources include [[Engineering:Terrestrial television|terrestrial broadcast]], direct broadcast satellite, digital cable, [[Engineering:Internet Protocol television|IPTV]], [[Engineering:Blu-ray|Blu-ray]] 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 [[Engineering:ATSC tuner|ATSC tuner]] via a [[Engineering:Television antenna|TV aerial]]. Laws prohibit homeowners' associations and city government from banning the installation of antennas.{{Citation needed|date=September 2019}}

Standard 35mm [[Engineering:Photographic film|photographic film]] used for cinema projection has a much higher [[Image resolution|image resolution]] than HDTV systems, and is exposed and projected at a rate of 24 [[Frame rate|frames per second]] (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 [[Engineering:Telecine#2:3 pulldown|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 ==
{{Main|Engineering:High-definition pre-recorded media and compression}}

HDTV can be recorded to [[Engineering:D-VHS|D-VHS]] (Digital-VHS or Data-VHS), W-VHS (analog only), to an HDTV-capable [[Engineering:Digital video recorder|digital video recorder]] (for example [[Company:DirecTV|DirecTV]]'s high-definition digital video recorder, [[Engineering:Sky+ HD|Sky HD]]'s [[Engineering:Set-top box|set-top box]], [[Company:Dish Network|Dish Network]]'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 [[Engineering:TiVo|TiVo]]'s Series 3 or HD recorders), or an HDTV-ready [[Home theater PC|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.{{Citation needed|date=August 2020}}

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 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.{{Citation needed|date=August 2020}}

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.{{Citation needed|date=August 2020}}

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"<!--quoted from agreement?--> [[Engineering:IEEE 1394|FireWire]] (IEEE 1394) on request. None of the [[Engineering:Satellite television|direct broadcast satellite]] providers have offered this feature on any of their supported boxes, but some [[Engineering:Cable television|cable TV]] companies have. {{As of|2004|alt=As of July 2004}}, boxes are not included in the FCC mandate. This content is protected by encryption known as 5C.<ref>{{cite web|url=http://www.dtcp.com/data/wp_spec.pdf|title=5C Digital Transmission Content Protection White Paper|access-date=2006-06-20|date=1998-07-14 |archive-url = https://web.archive.org/web/20060616075812/http://dtcp.com/data/wp_spec.pdf <!-- Bot retrieved archive --> |archive-date = 2006-06-16}}</ref> This encryption can prevent duplication of content or simply limit the number of copies permitted, thus effectively denying most if not all [[Social:Fair use|fair use]] of the content.{{Citation needed|date=August 2020}}

== See also ==
* [[Engineering:Display motion blur|Display motion blur]]
* Glossary of video terms
* [[High Efficiency Video Coding]]
* [[Engineering:List of digital television deployments by country|List of digital television deployments by country]]
* [[Engineering:Optimum HDTV viewing distance|Optimum HDTV viewing distance]]
* [[Engineering:Ultra-high-definition television|Ultra-high-definition television]] (UHD or UHDTV)

== References ==
{{reflist}}

== Further reading ==
* Joel Brinkley (1997), ''Defining Vision: The Battle for the Future of Television'', New York: Harcourt Brace.
* [https://www.amazon.com/High-Definition-Television-Development-Implementation/dp/0786449756 High Definition Television: The Creation, Development and Implementation of HDTV Technology] by Philip J. Cianci (McFarland & Company, 2012)
* [https://archive.today/20130112230757/http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=0521826241 Technology, Television, and Competition] (New York: Cambridge University Press, 2004)

== External links ==
;History
* [http://www.crit.rai.it/eletel/2005-3/53-4.htm L'Alta Definizione a Torino 1986–2006]{{snd}} the Italian HDTV experience from 1980s to 2006{{snd}} in Italian{{snd}} C.R.I.T./RAI
* [https://web.archive.org/web/20130603183845/http://hdtvarchiveproject.com/ The HDTV Archive Project]

;European adoption
* [http://tech.ebu.ch/docs/techreview/trev_299-ive.pdf Images formats for HDTV], article from the EBU, Technical Review
* [http://tech.ebu.ch/docs/techreview/trev_300-wood.pdf High Definition for Europe{{snd}} a progressive approach], article from the EBU, Technical Review
* [http://tech.ebu.ch/docs/tech/tech3299.pdf High Definition (HD) Image Formats for Television Production], technical report from the EBU

{{TV resolution}}
{{High-definition}}
{{Video formats}}

[[Category:High-definition television]]
[[Category:Consumer electronics]]
[[Category:Digital television]]
[[Category:Television technology]]
[[Category:Television terminology]]

{{Sourceattribution|High-definition television}}