High-definition television

High-definition television (HDTV) is a television system providing an image resolution that is of substantially higher resolution than that of standard-definition television. This can be either analog or digital. HDTV is the current standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television, Blu-rays, and streaming video.

HDTV may be transmitted in various formats:

  • 720p 1280×720p: 923,600 pixels (~0.92 MP) per frame
  • 1080i 1920×1080i: 1,036,800 pixels (~1.04 MP) per field or 2,073,600 pixels (~2.07 MP) per frame
  • 1080p 1920×1080p: not a broadcast standard for ATSC 1.0
    • 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

The letter "p" here stands for progressive scan, while "i" indicates interlaced.

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.[1] HDTV as is known today first started official broadcasting in 1989 in Japan, under the MUSE/Hi-Vision analog system.[2] HDTV was widely adopted worldwide in the late 2000s.[3]


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 more HD 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.[4] In 1938 France followed with their own 441-line system, variants of which were also used by a number of other countries. The US NTSC 555-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 similarly higher resolutions, first with the US NTSC color system in 1953, which was compatible with the earlier monochrome systems and therefore had the same 525 lines of resolution. European standards did not follow until the 1960s, when the PAL and SECAM color systems were added to the monochrome 625 line broadcasts.

The Nippon Hōsō Kyōkai (NHK, the 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[5]

Since the formal adoption of digital video broadcasting's (DVB) widescreen HDTV transmission modes in the mid to late 2000s; the 525-line NTSC (and PAL-M) systems, as well as the European 625-line PAL and SECAM 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 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 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.[6]

In 1986, the European Community proposed 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 Digital Video Broadcasting (DVB) project was formed, which would foresee development of a digital HDTV standard.[7]


In 1979, the Japanese public broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio.[8] The system, known as Hi-Vision or MUSE after its 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.[9] 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.[10] NHK taped the 1984 Summer Olympics with a Hi-Vision camera, weighing 40 kg.[11]

Satellite test broadcasts started June 4, 1989, the first daily high-definition programs in the world,[12] with regular testing starting on November 25, 1991 or "Hi-Vision Day" – dated exactly to refer to its 1,125-lines resolution.[13] 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.

Demise 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). Japan remained the only country with successful public broadcasting 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.[14] A Hi-Vision VCR from 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.[15] 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.[16] By mid-1993 prices of receivers were still as high as 1.5 million yen (US$15,000).[17]

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.[18] 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.[19] That year NHK started development of digital television in an attempt to catch back up to America and Europe. This resulted in the ISDB format.[20] Japan started digital satellite and HDTV broadcasting in December 2000.[11]

Rise of digital compression

Since 1972, International Telecommunication Union's radio telecommunications sector (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 also led to the acceptance of recommendations ITU-R BT.709.[21] In anticipation of these standards the Digital Video Broadcasting (DVB) organisation was formed, an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies. The DVB develops and agrees upon specifications which are formally standardised by ETSI.[22]

DVB created first the standard for DVB-S digital satellite TV, 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 Grand Alliance proposed 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 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, and the scan modes 1080i (1,080 actively interlaced lines of resolution) and 1080p (1,080 progressively scanned lines). The British Freeview HD 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,[23] 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.)

Inaugural HDTV broadcast in the United States

HDTV technology was introduced in the United States in the late 1980s 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, General Instrument, Philips, Sarnoff, Thomson, Zenith and the Massachusetts Institute of Technology. Field testing of HDTV at 199 sites in the United States was completed August 14, 1994.[24] 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 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.[25][26][27] The American Advanced Television Systems Committee (ATSC) HDTV system had its public launch on October 29, 1998, during the live coverage of astronaut John Glenn's return mission to space on board the Space Shuttle Discovery.[28] 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.[28][29] The first HDTV logo was created by Washington, DC-based advertising firm Don Schaaf & Friends, Inc.

European HDTV broadcasts

The first HDTV transmissions in Europe, albeit not direct-to-home, began in 1990, when the Italian broadcaster RAI used both HD-MAC and MUSE HDTV technologies to broadcast the 1990 FIFA World Cup. 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 to Barcelona and then with a fiber optic connection from Barcelona to Madrid.[30][31] 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. 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.[32]

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.[33] The HD1 channel was initially 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.

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,[34] 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).[35]

In December 2009, the United Kingdom became the first European country to deploy high definition content using the new DVB-T2 transmission standard, as specified in the Digital TV Group (DTG) D-book, on digital terrestrial television.

The Freeview HD service currently contains 13 HD channels (as of April 2016) 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 transmission standard.

In October 2008 France deployed five high definition channels using DVB-T transmission standard on digital terrestrial distribution.


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 scanning 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: [frame size][scanning system][frame or field rate] or [frame size]/[frame or field rate][scanning system].[36] 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 pixels 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.

50 Hz systems support three scanning rates: 50i, 25p and 50p. 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. 60 Hz 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.[37]

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 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) 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

Video format supported [image resolution] Native resolution [inherent resolution] (W×H) Pixels Aspect ratio (W:H) Description
Actual Advertised (Megapixels) Image Pixel
(HD ready)
786,432 0.8 4:3 1:1 Typically a PC resolution (XGA); also a native resolution on many entry-level plasma displays with non-square pixels.
921,600 0.9 16:9 1:1 Standard HDTV resolution and a typical PC resolution (WXGA), frequently used by high-end video projectors; also used for 750-line video, as defined in SMPTE 296M, ATSC A/53, ITU-R BT.1543.
1,049,088 1.0 683:384
(approx. 16:9)
1:1 A typical PC resolution (WXGA); also used by many HD ready TV displays based on LCD technology.
(full HD)
2,073,600 2.1 16:9 1:1 Standard HDTV resolution, used by full HD and HD ready 1080p TV displays such as high-end LCD, plasma and rear projection TVs, and a typical PC resolution (lower than WUXGA); also used for 1125-line video, as defined in SMPTE 274M, ATSC A/53, ITU-R BT.709;
Video format supported Screen resolution (W×H) Pixels Aspect ratio (W:H) Description
Actual Advertised (Megapixels) Image Pixel
(HD Ready)
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.
(Full HD)
1,555,200 1.6 16:9 4:3 Used for anamorphic 1125-line video in the HDCAM and HDV formats introduced by Sony and defined (also as a luminance subsampling matrix) in SMPTE D11.
(Full HD)
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 standard-definition television (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 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 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 and DVB define the following frame rates for use with the various broadcast standards:[38][39]

  • 23.976 Hz (film-looking frame rate compatible with NTSC 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 roll out 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.[40]

Types of media

Standard 35mm photographic film used for cinema projection has a much higher image resolution than HDTV systems, and is exposed and projected at a rate of 24 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 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.

Modern systems

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 (most sets sold since 2009 have this). This is achieved with a TV aerial, just as it has been since the 1940s except now the major network signals are broadcast in high definition (ABC, Fox, and Ion Television broadcast at 720p resolution; CBS, My Network TV, NBC, PBS at 1080i; and The CW at either resolution depending on the local affiliate). As their digital signals more efficiently use the broadcast channel, many broadcasters are adding multiple channels to their signals. Laws about antennas were updated before the change to digital terrestrial broadcasts. These new laws prohibit home owners' associations and city government from banning the installation of antennas.

Additionally, cable-ready TV sets can display HD content without using an external box. They have a QAM tuner built-in and/or a card slot for inserting a CableCARD.[41]

High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable, IPTV (including GoogleTV, Roku boxes and AppleTV or built into "Smart Televisions"), Blu-ray video disc (BD), and internet downloads.

Sony's PlayStation 3 has extensive HD compatibility because of its built in Blu-ray disc-based player, so does Microsoft's Xbox 360 with the addition of Netflix and Windows Media Center HTPC streaming capabilities. On November 18, 2012, Nintendo released a next generation high definition gaming platform, The Wii U, which includes TV remote control features in addition to IPTV streaming features like Netflix. The HD capabilities of the consoles has influenced some developers to port games from past consoles onto the PS3, Xbox 360 and Wii U, often with remastered or upscaled graphics.

Recording and compression

HDTV can be recorded to D-VHS (Digital-VHS or Data-VHS), W-VHS (analog only), to an HDTV-capable digital video recorder (for example DirecTV's high-definition Digital video recorder, Sky HD's set-top box, Dish Network's VIP 622 or VIP 722 high-definition Digital video recorder receivers, or TiVo'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 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) on request. None of the direct broadcast satellite providers have offered this feature on any of their supported boxes, but some cable TV companies have. As of July 2004, boxes are not included in the FCC mandate. This content is protected by encryption known as 5C.[42] This encryption can prevent duplication of content or simply limit the number of copies permitted, thus effectively denying most if not all fair use of the content.

See also


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Further reading

External links

European adoption
5.1 surround sound

5.1 surround sound ("five-point one") is the common name for six channel surround sound audio systems. 5.1 is the most commonly used layout in home theatre. It uses five full bandwidth channels and one low-frequency effects channel (the "point one"). Dolby Digital, Dolby Pro Logic II, DTS, SDDS, and THX are all common 5.1 systems. 5.1 is also the standard surround sound audio component of digital broadcast and music.All 5.1 systems use the same speaker channels and configuration, having a front left and right, a center channel, two surround channels and the low-frequency effects channel designed for a subwoofer.

Advanced Television Systems Committee

The Advanced Television Systems Committee (ATSC) is the group, established in 1982, that developed the eponymous ATSC standards for digital television in the United States. These standards have also been adopted by Canada, Mexico, South Korea and recently Honduras, and are being considered by other countries.

Airtel digital TV

Bharti Telemedia Limited d/b/a Airtel digital TV is an Indian direct-broadcast satellite service provider owned and operated by Bharti Airtel. Its satellite service, launched in October 2008, transmits digital satellite television and audio to households in India. It has a total subscriber base of 10.07 million as of 30 March 2015.

Analog high-definition television system

Analog high-definition television was an analog video broadcast television system developed in the 1930s to replace early experimental systems with as few as 12-lines. On 2 November 1936 the BBC began transmitting the world's first public regular analog high-definition television service from the Victorian Alexandra Palace in north London. It therefore claims to be the birthplace of television broadcasting as we know it today. John Logie Baird, Philo T. Farnsworth, and Vladimir Zworykin had each developed competing TV systems, but resolution was not the issue that separated their substantially different technologies, it was patent interference lawsuits and deployment issues given the tumultuous financial climate of the late 1920s and 1930s.

Most patents were expiring by the end of World War II leaving no worldwide standard for television. The standards introduced in the early 1950s stayed for over half a century.

(NOTE: Although UK's 405-line system was advertised as "high definition", due to it being higher than low-lined televisions, the picture quality isn't even close to standard definition and there were already higher resolutions available at the time)


BBC HD was a high-definition television channel provided by the BBC. The service was initially run as a trial from 15 May 2006 until becoming a full service on 1 December 2007 before closing on 26 March 2013. It broadcast only during the afternoon and evening and only broadcast material shot in High Definition, either in a simulcast with another channel or by inserting a repeat of a HD programme.

The channel featured a mix of programming including new episodes of Top Gear, Doctor Who and Hustle, repeats of HD programmes including Planet Earth, Bleak House and Torchwood as well as live coverage of large events such as The Proms, Wimbledon, the Eurovision Song Contest and the FIFA World Cup.

The channel was replaced by a HD simulcast of BBC Two, partly as a result of budget cuts affecting the entire corporation.


Cignal (pronounced as signal) is a subscription-based Direct-To-Home (DTH) satellite television service and Internet Protocol television provider in the Philippines. Cignal is owned by Cignal TV Inc., a wholly owned subsidiary of the MediaQuest Holdings Inc. under the PLDT Beneficial Trust Fund.For subscribers to receive Cignal broadcasts, they may either have it through satellite broadcast or through the internet. Its IPTV service is availed through PLDT in which the digital set-top box is connected with the optical network terminal through a ethernet cable. Cignal’s prepaid electronic loading system, is powered by the prepaid loading platform of Smart Communications, Inc. Cignal uses VideoGuard encryption system to protect its content from signal piracy. Cignal TV is using the SES-7 satellite to provide optimal coverage directly to the target markets.Cignal offers both Prepaid and Postpaid plans as low as ₱100 and high as ₱1990 per month.

They transmit 89 SD channels, 32 HD channels, and 12 audio channels. They offer Pay-per-view services as well as streaming services.Cignal uses the DVB-S2 digital television broadcast standard to accommodate both Standard Definition (SD) and High Definition (HD) TV broadcasts.

As of June 2018, Cignal reached the 2,000,000 subscribers mark.

Cignal operates a premium movie channel named Cignal 24/7 Pinoy Pay-Per-View.

Prepaid and Postpaid subscribers can watch movies at ₱30 on channel 196.


d2h is an Indian pay TV brand, part of Dish TV India Ltd providing direct broadcast satellite service—including satellite television, audio programming, and interactive television services to commercial and residential customers in India. As of December 31, 2017, d2h has a market share of 19% among the pay DTH operators. Dish TV India and d2h merger has been concluded, which has created the largest DTH service provider in the country with a subscriber base of about 29 million.

Dish México

Dish México, S. de R. L. de C.V. (In Mexico: Alcanzca) is a Mexican-owned company that operates a subscription satellite television service in México nationwide. S. de R. L. de C.V., stands for Sociedad de Responsabilidad Limitada de Capital Variable, a form of limited company. It is owned by MVS Comunicaciones 51% and Dish Network Corporation 49%.

Dolby AC-4

Dolby AC-4 is an audio compression technology developed by Dolby Laboratories. Dolby AC-4 bitstreams can contain audio channels and/or audio objects. Dolby AC-4 has been adopted by the DVB project and standardized by the ETSI.

High-definition television in the United Kingdom

High-definition television in the United Kingdom is available via cable, IPTV, satellite and terrestrial television. The first high-definition broadcasts began in 2006 and since then the number of channels available to view has grown to a maximum of 87 that can be viewed on pay-TV service, Sky.The majority of channels in the United Kingdom remain broadcast, and largely viewed, in standard-definition but most major broadcasters have begun or are soon beginning their initial forays into high-definition television. Similarly, the vast majority of viewing still takes place in standard-definition though penetration of high-definition displays and receivers is increasing.

High-definition broadcasts are available on satellite services: Freesat, Freesat from Sky and Sky; cable services Smallworld Cable and Virgin TV and terrestrial Freeview HD.

High-definition television in the United States

High-definition television (HDTV) in the United States was introduced in 1998 and has since become increasingly popular and dominant in the television market. Hundreds of HD channels are available in millions of homes and businesses both terrestrially and via subscription services such as satellite, cable and IPTV. HDTV has quickly become the standard, with about 85% of all TVs used being HD as of 2018. In the US, the 720p and 1080i formats are used for linear channels, while 1080p is available on a limited basis, mainly for pay-per-view and video on demand content.

Real VU

RealVU (stylized as Real VU) is the first Direct-To-Home (DTH) satellite service provider of Bangladesh. Incorporated in 2013,Beximco Communications Limited is a joint venture between Beximco Holdings Limited and General Satellite Group AG. In 2016, it has launched Bangladesh's first Direct-to-Home (DTH) satellite TV service under the "RealVU" brand name. RealVU offers a variety of digital International and Bangla channels ranging from entertainment, sports, movies and music to news and documentaries. The service is provide over 114 channels including 13 HD to the subscribers currently and more channels will be added latter on. The service is intercepted via ABS2 satellite.

Spaceway F2

Spaceway F2 is part of DirecTV’s constellation of direct broadcast satellites. The satellite was launched via an Arianespace Ariane 5 ECA rocket from Kourou, French Guiana on November 16, 2005. Its operational position is in geosynchronous orbit 35,800 kilometres (22,200 mi) above the equator at 99.2 degrees west longitude. SPACEWAY-2 is a Boeing 702-model satellite with a 12-year life expectancy. It is expected to support high definition television to DirecTV customers with its Ka-band communications payload. Although SPACEWAY-2 was originally built by Boeing to be used for broadband Internet access via HughesNet, it has been retrofitted to deliver HD local channels (NBC, ABC, CBS, & Fox) to numerous markets nationwide.

On April 19, 2006 the satellite was delivered to DirecTV's control after successful on-orbit testing. SPACEWAY-2 immediately started broadcasting HD locals to DirecTV customers in eight more markets: Minneapolis, Minnesota; Sacramento and San Diego, California; Pittsburgh, Pennsylvania; Nashville, Tennessee; Kansas City, Missouri.; Columbus, Ohio; and Birmingham, Alabama. Satellites named DirecTV-10 (launched 2007) and DirecTV-11 (launched 2008), constructed by Boeing, also for use in high definition television, are bent-pipe Ka-band satellites instead of regenerative satellites, and are being used to continue the expansion of DirecTV's HD services.

SPACEWAY-2 was originally envisioned as a global Ka-band communications system.

Boeing retrofitted the SPACEWAY-2 satellite for bent-pipe Ka-band communications for use in high definition television and disabled the regenerative on-board processing of the original system that was to be used for the SPACEWAY broadband satellite communications.

DirecTV-11 is co-located with SPACEWAY-2 satellites in order to use the 500 MHz of unused spectrum for HDTV broadcasting. This spectrum was originally intended for the broadband internet capabilities of the two SPACEWAY satellites which were disabled by Hughes at the request of DirecTV.

Sun Direct

Sun Direct is an Indian direct broadcast satellite service provider. Its satellite service, launched in December 2017, transmits digital satellite television and audio to households in India. Sun Direct uses MPEG-4 digital compression, transmitting HD Channels on GSAT-15 Sun Direct at 93.5°E. and SD Channels on MEASAT-3 at 91.5°E.

Tata Sky

Tata Sky is an Indian direct broadcast satellite television provider in India, using MPEG-4 digital compression technology, transmitting using INSAT-4A and GSAT-10 satellite. Incorporated in 2004, Tata Sky is a joint venture between the Tata Group, and The Walt Disney Company with Temasek Holdings as a minor partner. It was started as a joint venture between Tata Group and 21st Century Fox.

It currently offers total 601 channels, 495 SD channels and 99 HD channels and services, along with other many active services.

Tata Sky entered into an agreement with French firm Technicolor to supply 4K set top boxes from early 2015.

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 NHK Science & Technology Research Laboratories and later defined and approved by the International Telecommunication Union (ITU).The Consumer Electronics Association announced on October 17, 2012, that "Ultra High Definition", or "Ultra HD", would be used for displays that have an aspect ratio of 16:9 or wider and at least one digital input capable of carrying and presenting native video at a minimum resolution of 3840×2160 pixels. In 2015, the Ultra HD Forum was created to bring together the end-to-end video production ecosystem to ensure interoperability and produce industry guidelines so that adoption of ultra-high-definition television could accelerate. From just 30 in Q3 2015, the forum published a list up to 55 commercial services available around the world offering 4K resolution.The "UHD Alliance", an industry consortium of content creators, distributors, and hardware manufacturers, announced during a Consumer Electronics Show (CES) 2016 press conference its "Ultra HD Premium" specification, which defines resolution, bit depth, color gamut, high-dynamic-range imaging (HDRI) and rendering (HDRR) required for Ultra HD (UHDTV) content and displays to carry their Ultra HD Premium logo.

Ultra HD Blu-ray

Ultra HD Blu-ray is a digital optical disc data storage format that supersedes Blu-ray. Ultra HD Blu-ray discs are incompatible with existing Blu-ray players. Ultra HD Blu-ray supports 4K UHD (3840 × 2160 resolution) video at frame rates up to 60 frames per second, encoded using High Efficiency Video Coding. The discs support both high dynamic range by increasing the color depth to 10-bit per color and a greater color gamut than supported by conventional Blu-ray video by using the Rec. 2020 color space.

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 purpose computers), and in video processors that perform functions such as image resizing, image rotation, deinterlacing, and text and graphics overlay. It is conveyed over various types of baseband digital video interfaces, such as HDMI, DVI, DisplayPort and SDI. Standards also exist for carriage of uncompressed video over computer networks.

Some HD video cameras output uncompressed video, whereas others compress the video using a lossy compression method such as MPEG or H.264. In any lossy compression process, some of the video information is removed, which creates compression artifacts and reduces the quality of the resulting decompressed video. When editing video, it is preferred to work with video that has never been compressed (or was losslessly compressed) as this maintains the best possible quality, with compression performed after completion of editing.

High-definition (HD)
Analog broadcast
(All defunct)
Digital broadcast
Filming and storage
HD media and

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