High-definition television

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High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats (NTSC, SÉCAM, PAL) allow. Except for early analog formats in Europe and Japan, HDTV is broadcasted digitally, and therefore its introduction sometimes coincides with the introduction of digital television (DTV).

Historically, the term high-definition television was also used to refer to television standards developed in the 1930s to replace the early experimental systems, although, not so long afterwards, Philo T. Farnsworth, John Logie Baird 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 '20s and '30s. Most patents were expiring by the end of World War II leaving the market wide open and no worldwide standard for television agreed upon. The world used analog PAL, NTSC, SÉCAM and other standards for over half a century.

HDTV is defined as 1080 active lines, 16 x 9 aspect ratio in ITU-R BT.709.

Contents 1 Notation 1.1 Standard resolutions 1.2 Standard frame or field rates 2 Comparison to SDTV 2.1 Close-up view 3 Format considerations 4 Technical details 5 Advantages of HDTV expressed in non-engineering terms 6 Early systems 6.1 French 755i 6.2 MUSE 6.2.1 MUSE in Operation 6.3 HD-MAC 7 Contemporary systems 7.1 Asia 7.1.1 Japan 7.1.2 Republic of Korea 7.2 Australia 7.3 Europe 7.4 North America 7.4.1 Canada 7.4.2 Mexico 7.4.3 United States 7.5 South America 7.5.1 Argentina 7.5.2 Brazil 8 Recording, compression, and prerecorded media 8.1 Future media 8.1.1 Microsoft 8.1.2 Broadcasters 8.1.3 Online HD 8.1.4 VP6 8.1.5 HD DVD and Blu-ray 8.1.6 HD cameras 9 Table of terrestrial HDTV transmission systems 10 References 11 See also 12 External links

Notation

In the context of HDTV, the formats of the broadcasts are referred to using a notation describing:

• The number of lines in the display resolution.
• Progressive frames (p) or interlaced fields (i).
• Number of frames or fields per second.

For example, the format 720p60 is 1280 × 720 pixels, progressive encoding with 60 frames per second (60 hertz known as Hz). The format 1080i50 is 1920 × 1080 pixels, interlaced encoding with 50 fields (25 frames) per second. Often the frame or field rate is left out. It can then usually be assumed to be either 50 or 60, although some displays claim to support 1080p, but only support 1080p/30. Consumer displays are available that allow 1080p/60 input and render it at full temporal and spatial resolution.

A frame or field rate can also be specified without a resolution. For example 24p means 24 progressive frames per second and 50i means 25 interlaced frames per second.

Most HDTV systems support some standard resolutions and frame or field rates. The most common are:

Standard resolutions

Image:Videores.png

Note: this graphic ignores the impact of interlaced artifacts, which would further reduce the vertical resolution

• Normal NTSC (Also known as D1) is 720x486
• NTSC DV is 720x480

Standard frame or field rates

• 24p (cinematic film)
• 25p
• 30p
• 50p
• 60p
• 50i (PAL)
• 60i (NTSC)

Comparison to SDTV

HDTV has at least twice the resolution of SDTV, thus allowing much more detail to be shown compared to analog television or regular DVD. In addition, the technical standards for broadcasting HDTV are also able to handle 16:9 aspect ratio pictures without using letterboxing, thus further increasing the effective resolution for such content.

Close-up view

HDTV at four times the resolution of SDTV.

SDTV resolution.

Format considerations

The optimum format for a broadcast depends on the type of media used for the recording and the characteristics of the content. The field and frame rate should match the source, as should the resolution. On the other hand, a very high resolution source may require more bandwidth than is available in order to be transmitted without loss of fidelity. The lossy compression that is used in all digital HDTV storage/transmission systems will then cause the received picture to appear distorted when compared to the uncompressed source.

Photographic film destined for the theater typically has a high resolution and is photographed at 24 frame/s. Depending on the available bandwidth and the amount of detail and movement in the picture, the optimum format for video transfer is thus either 720p24 or 1080p24. When shown on television in countries using PAL, film must be converted to 25 frames per second by speeding it up by 4%. In countries using the NTSC standard, (60 fps) a technique called 3:2 pulldown is used. One film frame is held for three video fields, (1/20 of a second) and then the next is held for two video fields (1/30 of a second) and then the process repeats, thus achieving the correct film rate with two film frames shown in 1/12 of a second. (See also: Telecine)

Older (pre-HDTV) recordings on video tape such as Betacam SP are often either in the form 480i60 or 576i50. These may be upconverted to a higher resolution format (720i), but removing the interlace to match the common 720p format may distort the picture or require filtering which actually reduces the resolution of the final output. (See also: Deinterlacing)

Non-cinematic HDTV video recordings are recorded in either 720p or 1080i format. The format depends on the broadcast company if destined for television broadcast, however in other scenarios the format choice will vary depending on a variety of factors. In general, 720p is more appropriate for fast action as it uses progressive fields, as opposed to 1080i which uses interlaced fields and thus can have a degradation of image quality with fast motion. In addition, 720p is used more often with internet distribution of HD video, as all computer monitors are progressive, and most graphics cards do a sub-optimal job of de-interlacing video in real time. 720p Video also has lower storage and decoding requirements than 1080i or 1080p, and few people possess displays capable of displaying the 1920x1080 resolution without scaling. 720p appears at full resolution on a common 1280x1024 LCD, which can be found for under $250. An LCD capable of native 1080i resolution costs close to a thousand dollars, however models by Dell, HP and Gateway capable of displaying full 1080i and 1080p resolution have had price points lower than $1,000.

In North America, Fox, ABC, and ESPN (ABC and ESPN are both owned by Disney) currently broadcast 720p content. NBC, Universal HD (both owned by General Electric), CBS, HBO-HD, INHD, HDNet and TNT currently broadcast 1080i content.

Technical details

MPEG-2 is most commonly used as the compression codec for digital HDTV broadcasts. Although MPEG-2 supports up to 4:2:2 YUV chroma subsampling and 10-bit quantization, HD broadcasts use 4:2:0 and 8-bit quantization to save bandwidth. Some broadcasters also plan to use MPEG-4. Some German broadcasters already use MPEG-4 together with DVB-S2 (ProSieben, Sat1 and Three Premiere Channels). Recommended receiver is Humax PR-HD 1000, but others are announced as well as PCI cards. It seems likely that all European HDTV may be MPEG-4 and Ireland, which has not yet started ANY Digital Television, is considering MPEG4 for SD Digital as well as HDTV on Terrestrial broadcasts.

HDTV is capable of "theater-quality" audio because it uses the Dolby Digital (AC-3) format to support "5.1" surround sound.

The pixel aspect ratio of native HD signals is 1.0, or 1 pixel length = 1 pixel width. New HD compression and recording formats such as HDV use rectangular pixels for more efficient compression and to open HDTV acquisition for the consumer market.

For more technical details see the articles on HDV, ATSC, DVB, and ISDB, respectively.

Within television studios and other production and distribution facilities, the SMPTE 292M interconnect standard (a nominally 1.5 Gb/s, 75-ohm serial digital interface) is used to route uncompressed HDTV signals. The native bitrate of HDTV formats is highly excessive for over-the-air broadcast and consumer distribution media, hence the widespread use of compression in consumer applications. SMPTE 292M interconnects are generally unavailable in consumer equipment, partially due to the expense involved in supporting this format, and partially because consumer electronics manufacturers are required (typically by licensing agreements) to not provide unencrypted digital outputs on consumer video equipment, for fear that this would aggravate the issue of video piracy.

Advantages of HDTV expressed in non-engineering terms

1. All commercial HD is digital, so the signal will either deliver an excellent picture, a picture with noticeable pixelation, a series of still pictures, or no picture at all. You would never get a snowy or washed out image from a weak signal, effects from signal interference, such as herringbone patterns, or vertical rolling.
2. Most HD programming and films will be presented in the 16x9 proportioned, semi-widescreen format (though some films created in even wider ratios will still display "letterbox" bars on the top and bottom of even 16:9 sets.) Older films and programming that retain their 4:3 ratio display will be presented in a version of letterbox commonly called "pillar box", displaying bars on the right and left of 16:9 sets (rendering the term "fullscreen" a misnomer). Or, one can usually choose to enlarge the image to fill the screen, however this option will display a distorted, stretched-out picture.
3. The colors will generally look more realistic, due to the cleaner signal.
4. The visual information is about 2-5 times more detailed overall. The gaps between scanning lines are smaller or invisible. Legacy TV content that was shot and preserved on 35mm film can now be viewed at nearly the same resolution as that at which it was originally photographed.
5. Two new pre-recorded disc formats will be available in spring 2006. One is called HD DVD, the other is Blu-ray. Both systems will usually play current DVDs, and attempt to extract a near-HDTV-quality image from them, but they are not compatible with each other.
6. The increased clarity and detail make larger screen sizes more comfortable and pleasing to watch.
7. Dolby Digital 5.1 sound is broadcast along with standard HDTV video signals allowing full surround sound capabilities. (standard television signals broadcast basic stereo audio signals)

Early systems

French 755i

When Europe resumed TV transmissions after WWII, i.e. in the late-1940s and early-1950s, different countries used different resolutions. The UK used 405 lines, most other countries 625 lines (both numbers include the vertical gap, the actual resolutions were lower), but France decided in 1948 to go for 819 lines. The French TV system thus became the world's first HDTV system, and, by today's standards, the French system could be called 755i (not all lines could be used for the actual image — some lines were lost during the vertical retrace). The French 819-line (or 755i) HDTV system was introduced in the 1950s. When, in the late-1960s, a second TV channel and color TV were introduced in Europe, the UK dropped its 405-line TV system (completely in 1985) and France dropped its 819-line system (again, with final transmissions from Paris in 1985), making all European countries agree to use 625 lines (576i) for their TV transmissions.

The French "755i" 819-line HDTV system was used in only France, Belgium and Monaco, and in France only for the first French TV channel. It was discontinued in 1986. It was used only for black-and-white TV; color TV in 819-line SECAM never went beyond the experimental stage. It was transmitted only on VHF channels, and a French 819-line TV channel occupied 14 MHz of bandwidth. The system was therefore not PAL, SECAM or CCIR601-derived.

MUSE

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Japan has the earliest working HDTV system still in use, with design efforts going back to 1979. Japan began broadcasting analog HDTV signals in the early 1990s using an interlaced resolution of 1035 lines (1035i). The Japanese MUSE system, developed by NHK Science and Technical Research Laboratories (STRL) in the 1980s, employed filtering tricks to reduce the original source signal to decrease bandwidth utilization.

MUSE in Operation

• In the typical setup, three picture elements on a line were actually derived from three separate scans. Moving images were thus blurred in a manner similar to using 16mm movie film for HDTV projection.
• Stationary images were transmitted at full resolution.
• Whole-camera pans would result in a loss of 50% of horizontal resolution.
• Considering the technological limitations of the time, MUSE was a very cleverly-designed analog system.
• MUSE had a bit-reduced stereo audio transmission system that was notable in its design as it was not psychoacoustical like Musicam.

Though Japan has since switched to a digital HDTV system based on ISDB, the original MUSE-based BS Satellite channel 9 (NHK BS Hi-vision) is still being broadcast. It broadcasts the same programs as BS-digital channel 103, but will end sometime in 2007.

HD-MAC

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The European Commission established a European standard for uncompressed digital HDTV in a 1986 directive (MAC). However, it never became popular among broadcasters. It was required that all high-powered satellite broadcasters use MAC from that year. Owing to the advance of technology and the launch of middle-powered satellites by SES Astra, broadcasters could avoid MAC, and lower transmission costs. HD-MAC (the high-definition variant of MAC) was left for transcontinental satellite links, however.

Another reason for HD-MAC's failure is that it was not realistic to use 36 MHz for a high-definition signal in terrestrial broadcasting (SDTV uses 6-, 7- (VHF), or 8-MHz (UHF)). HD-MAC could be used only by cable and satellite providers, where there is a wider bandwidth available. Thus, analog HDTV could not replace conventional SDTV (terrestrial) PAL/SECAM, making HD-MAC sets unattractive to potential consumers.

The HD-MAC standard was abandoned in 1993, and since then all EU and EBU efforts have focused on the DVB system (Digital Video Broadcasting), which allows both SDTV and HDTV.

See also: COUNCIL DIRECTIVE 92/38/EEC of 11 May 1992.

Contemporary systems

Asia

Japan

Japan had pioneered HDTV for decades with an analog implementation. The old system is not compatible with the new digital standards. Japan terrestrial broadcast of HD via ISDB-T started in December 2003. It is reported that two million HD receivers have been sold in Japan already.

Republic of Korea

After a long controversy between the government and broadcasters, ATSC was chosen over DVB-T. From 2005, digital services are available in all the country.

It is required that at least 10 hours of HD content to be broadcast on a weekly basis during the first year of commercial digital service.

Australia

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Australia started HD broadcasting in January 2001, but only in August 2003 was HD content mandated. Most cities in Australia that have a population of 40,000 or greater have at least one terrestrial DTV channel available (for example, Albany, Western Australia, has had DTV available for almost a year as of May, 2005). However, most Australian DTV broadcasters are still experimenting with HDTV transmission and DTV delivery.

(Edit:) As of April 2006 Australian Capital Cities are well and truly past the experimental stage. All have HD and standard definition (SD) Digital channels on commercial channels 7, 9 and 10. the ABC (Government Broadcaster) has two Digital channels, one of which is HD. The specialty 'ethnic' broadcaster SBS has one digital and one HD channel. Considerable HD content is now broadcast, including most news and current affairs, movies and some imports such as US sitcoms and cop shows, the UK police show "the Bill", and many 'nature' shows of the David Attenborough variety.

Most purchasers of large screen LCD and Plasma HD sets usually purchase a HD set top 'box' which currently costs around $ A 250 (around $200 US).

Europe

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Commercial HDTV services began in 2004 with Euro1080, a Belgian MPEG2/DVB-S pay channel. As for 2006, there has been a slow but steady increase in the number of HD channels available to European viewers in many countries. Although most of these channels are pay TV, there are some free to air HD stations available(Pro 7 & SAT.1), as well as technical transmissions by satellite. Image:Hd-ready.jpg The UK's first HDTV service began on 2 December 2005 when Telewest, a cable TV company now part of NTL, distributed HDTV programs to 400 customers in the south London area. On 10 March 2006 NTL confirmed that HDTV was available nationally in the former Telewest areas. Sky High-Definition has been confirmed to be available to the general public from 1 May 2006.

Throughout 2006, the British Broadcasting Corporation (BBC) has been running HDTV broadcast tests across digital platforms. Tested broadcasts include the BBC drama series Bleak House, Planet Earth, the Germany 2006 tournament and selected Wimbledon 2006 matches. More information is available from the BBC Press Office

A label "HD-ready" has been created to inform consumers of the benefits of High Definition. The purpose of the label is create a single norm to simplify the purchase of a HDTV in Europe.

North America

Canada

In Canada, on November 22 2003, CBC had their first broadcast in HD, in the form of the Heritage Classic outdoor NHL game between the Edmonton Oilers and the Montreal Canadiens. Bell ExpressVu, a Canadian satellite company, Rogers Cable and Videotron provide somewhat more than 21 HDTV channels to their subscribers including TSN HD, SportsNet HD, Discovery HD (Canadian Edition), The Movie Network HD, and several U.S. stations plus some PBS feeds and a couple of pay-TV movie channels. CTV Toronto broadcast in HD along with its western counterpart, BC CTV. They were also the first to broadcast a terrestrial HD digital ATSC signal in Canada. Global joined the crowd in late-2004. Other networks are continuing to announce availability of HD signals. CHUM Limited's Citytv in Toronto was the first HDTV broadcaster in Canada, however very few shows are shown in HDTV beyond the well-known ones such as CSI, ER, etc. as of early-2005. CBC officially launched HDTV programming on March 5 2005. StarChoice, another Canadian satellite provider, currently offers its subscribers 14 HDTV channels at no extra cost.

Mexico

Mexican television company Televisa made experimental HDTV broadcasts in the early-1990s, in collaboration with Japan's NHK. Some events now broadcast in high definition.

During the first half of 2005, at least one cable provider in Mexico City (Cablevision) has begun to offer 5 HDTV channels to subscribers purchasing a digital video recorder (DVR).

In 2005, TV Azteca signed a deal with Harris Corporation's broadcast communications division for digital TV transmitters and HDTV encoding equipment to bring high-definition TV to nine Mexican cities.

The launch will be carried out in two phases. By the third quarter of 2006, HDTV transmissions will be available in Mexico's largest markets: Mexico City, Guadalajara and Monterrey. Phase Two of the national rollout will bring HDTV services to six cities along the Mexico-U.S. border (Matamoros, Reynosa, Nuevo Laredo, Ciudad Juarez, Mexicali and Tijuana) through the first half of 2006. This rollout takes advantage of HDTV receivers already in place thanks to an earlier HDTV rollout by stations on the American side of the border.

Also, TV Azteca has planned to broadcast the Mexican football tournament in HDTV. And almost all retailers have started shipping televisions with HDTV tuners.

XETV in Tijuana, Baja California - across the border from San Diego, California - is on the air in HDTV using 720p format. This affiliate of the American Fox TV Network is on UHF channel 23 broadcasting from Mt. San Antonio in Tijuana, Mexico with 403,000 watts, directed primarily northward at San Diego. In January 2006, Televisa's XEFB-TV and Multimedios' XHAW-TV in Monterrey, Nuevo Leon began HDTV transmissions on UHF channels 48 and 50, respectively. In February 2006, Televisa's XHUAA in Tijuana began its HDTV transmissions on channel 20. Unfortunately they have no HDTV programs. Channel 20 broadcasts an upconverted version of the programs of XHUAA's analog signal on channel 57. In Guadalajara, Televisa channels 2 (XHGA HD),4 (XHG HD) and 9 (XEWO HD) are available in 1080i format, TV Azteca channels 31 and 33 broadcast in 480i format.

United States

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In the United States, HDTV specifications are defined by the ATSC. An HDTV-compatible TV usually uses a 16:9 aspect ratio display with an integrated ATSC tuner. Lower-resolution sources like regular DVDs may be upscaled to the native resolution of the TV.

South America

Argentina

While HDTV-ready TVs sales are increasing in this country, no single HD feed is available right now. The government is deciding which format will be used, but chances are American's ATSC will be chosen. Directv and local cable company "Cablevision" will also offer HDTV channels pack later this year.

Brazil

Since 2001 native 480p TVs are commercialized in Brazil mainly for DVD video support. In 2003 the first 1080i models were introduced (being capable to rescaling 720p) and native 720p LCD monitors in 2004 reached in the market.

The country is still deciding on which HDTV Standard is going to be implemented. The options are either a joint format consisted of the Japanese ISDB format, a H.264 compression scheme developed by Brazil's USP university [1] and Flex-TV or the European DVB standard, using H.264 compression derived from the French standard. ATSC may also be considered if Brazil Mercosur's ally Argentina choose this format.

Brazilian government is still pondering on which standard to choose based on something not so transmission related - The construction of a Semiconductor factory on the country financed by ST Electronics (if DVB is chosen) or by Nec, Sony, Panasonic and Toshiba (if ISDB is chosen). Neither side said they would certainly build the factory, but that's been a deciding factor the last few days.[2]

Broadcasting Companies, lead by Rede Globo, prefer the ISDB standard and believe that the promise of a Semiconductor Factory is the wrong detail to base the choice on. [3]

An official date for the decision has yet to be announced.

Recording, compression, and prerecorded media

HDTV can be recorded to D-VHS (Digital-VHS), W-VHS, to an HDTV-capable digital video recorder such as DirecTV's high-definition TiVo or Dish Network's DVR 921, 942 or VIP622, or to a computer equipped with an HDTV capture card. In the U.S., the only current archival option is D-VHS. D-VHS digitally records a 28.2-Mbit stream onto a classic VHS tape, using a FireWire (IEEE 1394) digital transport to carry a compressed MPEG-2 Transport Stream from the tuning device to the recorder.

However, the massive amount of data storage required to archive uncompressed streams make it unlikely that an uncompressed storage option will appear in the consumer market soon. Realtime MPEG-2 compression of an uncompressed digital HDTV signal is also prohibitively expensive for the consumer market at this time, but should become inexpensive within several years (although this is more relevant for consumer HD camcorders than recording HDTV). 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.

As part of the FCC's "plug and play" agreement, cable companies are required to provide customers that rent HD set-top boxes with a set-top box with "functional" Firewire (IEEE 1394) upon request. None of the DBS providers have offered this feature on any of their supported boxes. As of July 2004, boxes are not included in the FCC mandate. This content is protected by encryption known as 5C. This encryption can prevent someone from recording content at all or simply limit the number of copies.

Aside from scarce Japanese analog MUSE-encoded laser discs that are no longer produced, as of 2005 the only current available prerecorded HD media is D-Theater. Comprising less than 100 titles and utilizing a 28-Mbit/s MPEG2 stream at 720p or 1080i with either Dolby Digital 5.1 or DTS encoding, D-Theater is an encrypted D-VHS format, and only D-Theater capable D-VHS players can play back these tapes. This format is superior to broadcast HDTV due to its higher bandwidth and, of course, the ability to do non-realtime optimization of the encoding, which is not possible with broadcast HDTV. D-Theater is currently a small niche market even within the niche HDTV community, and it appears as if the final D-Theater title was published in 2004.

Future media

HD programming may be recorded on optical disc using Blu-ray Disc or HD DVD. Blu-ray technology is currently available only in Japan with a Japanese satellite/terrestrial tuner, but is expected to be released in other world markets on May 23, 2006. Blu-ray uses a blue-laser optical disc with an MPEG-2 or MPEG-4 codec. Sony will include a Blu-ray player in its forthcoming gaming console, the PlayStation 3, which was announced to be released during early November 2006. It is expected to have a big impact on the HDTV market. Similarly, Microsoft's Xbox 360 doesn't ship with an HD DVD-compatible player as standard at present (as opposed to Blu-Ray), but the company plans on releasing an external HD-DVD drive in the near future.

Many are regarding this difference in support for the two HD formats (provided Microsoft ship their HD-DVD drive in time) as the precursor to the next full-blown format war, and the indicator as to which format will win out in the end. Discussion is mainly centering around which of the consoles will reach sufficient numbers in terms of the at-home installation base to guarantee one HD format's success over the other (combined with the race to see which manufacturer can produce standalone players at reasonable price points, these two things - that, and movie studio support for the two formats - will be the main contributors to bringing the ownership of compatible devices to critical mass, and resolving the inevitable format war).

Microsoft

In an attempt to provide a bitrate-compatible high-definition format for high-definition video on standard DVD-ROMs, Microsoft introduced their Windows Media 9 Series codec with the ability to compress a high-definition bitstream into the same space as a conventional NTSC bitstream (approximately 5 to 9 megabits per second for 720p and higher). Microsoft is marketing its high-definition Windows Media 9 Series codec as WMV HD. It remains to be seen if the codec will be adopted for widespread use, if only as a Wi-Fi industry standard. As of November 2003, this format required a significant amount of processing power to encode and decode and the only commercially-available movie that used the codec was the Terminator 2: Extreme Edition DVD (see 1). Since then, more titles have become available in this format, such as the acclaimed surf documentary Step Into Liquid. In addition, mariposaHD, the world's first original HDTV show made for the Internet, is now distributing free 1080i and 720p videos in WMV HD format. As of the start of 2005, Microsoft recommends a 3.0 GHz processor with 512 MB of RAM and a 128-MB video card for 1080p playback on Windows XP, though there are now commercially available DVD players, like the KiSS DP-600, that will play back WMV HD DVD ROMs in high-definition on HDTV sets. The codec has been submitted to SMPTE and is in SMPTE's standardization process with an intent for it to become an official SMPTE standard known as VC-1 in the near-future.

Broadcasters

Other codecs are in contention such as H.264/AVC (MPEG-4 Part 10) and the VP6/VP7 codecs from On2 Technologies.

H.264 as a standard has already been selected and adopted by the biggest broadcasters in the U.S. (DirecTV, DISH Network) and Europe (BSkyB, Premiere, Canal+, TPS, ...). H.264 was chosen for several reasons: The standard was validated as an open standard at least a year before VC-1 was seriously considered as a potential open standard, and, then, there is a lot of uncertainty on the levies Microsoft may want to impose once the algorithm is adopted. So far, only a handful of very minor broadcasters are seriously considering VC-1. It has been thought for a while that VC-1 was better adapted for the IPTV world than H.264, but press announcements have also already been made by some of the largest STB manufacturers like Amino, Pace, Kreatel demonstrating solutions based on H.264 standards.

The main areas of dominance of VC-1 seem to currently be in the Blu-ray Disc (HD DVD has also announced support for VC-1) and, for obvious reason, the home PCs.

In fact, there is some concern in the community that Microsoft may have appropriated itself the H.264 standard, modified and improved upon it and are trying to resell the solution as VC-1, without providing dues to the MPEG-LA. However, this is currently a rumor and has not yet been challenged.

Example of broadcasters concerns.

Online HD

H.264 has made significant progress towards becoming a widespread video format on the internet thanks to Apple Computer's QuickTime software supporting the format as of version 7. Since many movie trailers are released in QuickTime format, when movie distributors started releasing HD trailers on the web the format they chose was H.264. H.264 is also used by some for encoding video podcasts.

VP6

VP6 was reported by On2 to have been chosen by China for use in the Enhanced Versatile Disc (EVD) format initiative. As reported, this was a result of China's desire to avoid royalties on WM9 or AVC. As an advantage, VP6 would not require royalties on recorded media (although royalties would be charged for player devices at a similar cost as for other codecs). As China starts to dominate manufacturing of TV and DVD units, the country's choice of standards becomes more important for everyone. A low cost for the codec itself is not a significant advantage over DVD, however, as the standalone hardware players will be incompatible with standard DVD-Video unless the manufacturer pays the royalties for the technologies necessary to make the player DVD-compatible. Very few titles were made available in any market for this format, although it is presumed that many would be needed to drive purchase of incompatible players. It is unlikely any major U.S. studio will commit to movies in this format without some form of copy-protection, which is not yet specified. Soon after the announcement that VP6 would be used on EVD, negotiations between On2 and E-World (the consortium pushing EVD to become a standard) broke down. On2 filed multiple breach of contract claims for arbitration, but in March of 2005 the arbitrator ruled that E-World had not broken the contract and owed nothing to On2. It was unclear to On2 and the arbitrator whether the Chinese government ever approved the EVD proposal as a standard.

HD DVD and Blu-ray

Since the DVD Forum and the Blu-ray Disc Association failed to agree on standards for high-definition 12-cm discs, a format war is now under way between the DVD Forum's HD DVD (formerly "Advanced Optical Disc") standard and the Blu-ray Disc Association's Blu-ray Disc standard. Both sides of the HD disc camps are already leveraging studio partners against each other through exclusive arrangements. As a result, this will likely lead to certain films becoming available only on one format. A probable outcome of a messy format war would be the emergence of combo players, as the physical disc sizes are identical. Another possibility is that the PlayStation 3 console (manufactured by Sony, the main advocate of Blu-ray Discs) will gain a major lead in sales for Blu-ray players when it launches in 2006. Universal Studios has announced exclusivity to HD DVD, while 20th Century Fox and Sony Pictures Entertainment are exclusive to Blu-ray. The remaining five major movie studios are supporting both.

Although they disagree about physical format technology, both the HD DVD and Blu-ray factions have selected the same three video codecs to be mandatory in their designs: specifically, MPEG-2 Part 2, VC-1, and H.264/AVC.

There are now some DVD players that will output enhanced or high-definition signals from standard-definition DVDs. These players, however, are not considered to be true HD DVD players since they only include an integrated scaler to upconvert the standard-definition DVD video to high-definition video. This upconversion process can improve the perceived picture quality of standard-definition video. Some DVD manufacturers such as Philips are licensing the DivX codec in order to play 720p/1080i content recorded on standard consumer DVD-R discs.

HD cameras

The standard for consumer/prosumer HDTV acquisition is High-Definition Video (HDV). It records MPEG-2 TS compressed HDTV video on standard DV media (regular DV or MiniDV cassette tape) and transfers it using FireWire. At this time all consumer/prosumer HD camcorders only record at a maximum resolution of 1440x1080. The image is then stretched from a 4:3 aspect ratio to a 16:9 aspect ratio. This means that even consumer or prosumer camcorders that claim 1080i resolution do not include the full horizontal resolution of 1,920 pixels per line. All major prosumer and consumer camcorder vendors provide cameras in this segment.

Broadcast-level HD camcorders and other cameras often record to hard drives via a raw input/output or to tape or flash cards in formats that support higher bitrates than standard DV cassettes such a DVCPro HD. Recording at 100 Mbits/s, it uses a better color compression method to give better color representation than a standard MiniDV or other DV25 cassette and less compression artifacts.

Table of terrestrial HDTV transmission systems

Main characteristics of three DTTV systems

Systems	ATSC	DVB-T	ISDB-T
Source coding
Video	Main Profile syntax of ISO/IEC 13818-2 (MPEG-2 – Video)
Audio	ATSC Standard A/52 (Dolby AC-3)	ISO/IEC 13818-2 (MPEG-2 – Layer II Audio) and Dolby AC-3	ISO/IEC 13818-7 (MPEG-2 – AAC Audio)
Transmission system
Channel coding
Outer coding	R-S (207, 187, t = 10)	R-S (204, 188, t = 8)
Outer interleaver	52 R-S block	12 R-S block
Inner coding	rate 2/3 trellis code	PCC: rate 1/2, 2/3, 3/4, 5/6, 7/8; constraint length = 7, Polynomials (octal) = 171, 133
Inner interleaver	12 to 1 trellis code	bit-wise, frequency	bit-wise, frequency, selectable time
Data randomization	16-bit PRBS
Modulation	8-VSB and 16-VSB	COFDM QPSK, 16QAM and 64QAM Hierarchical modulation: multi-resolution constellation (16QAM and 64QAM) Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol Two modes: 2k and 8k FFT	BST-COFDM with 13 frequency segments DQPSK, QPSK, 16QAM and 64QAM Hierarchical modulation: choice of three different modulations on each segment Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol Three modes: 2k, 4k and 8k FFT

References

• United States Federal Standard 1037C
• DTV channel protection ratios
• DVB HDTV standard
• Images formats for HDTV, article from the EBU Technical Review .
• High Definition for Europe - a progressive approach, article from the EBU Technical Review .
• High Definition (HD) Image Formats for Television Production, technical report from the EBU
• Digital Terrestrial HDTV Broadcasting in Europe , technical report from the EBU
• TV Azteca Plans HDTV Mexican Rollout

See also

• Advanced Television Systems Committee (ATSC)
• ATSC tuner
• Integrated Services Digital Broadcasting
• DVB (Digital Video Broadcasting)
• Digital television
• HDTV input and colorspace (YPbPr/YCbCr).
• HD ready
• Ultra-High Definition Video (UHDV)

External links

Template:Wikiquote Template:Wiktionarypar

• ATSC
• CDTV Canadian Digital Television official website
• HDTV Info Information on HDTV
• Sky HD Sky HDTV - official site
• MadCityHD.com South-Central Wisconsin's HDTV Resource (Madison, WI)
• HDTV Magazine HDTV Resource
• HD Beat High definition consumer information, listings and reviews.
• Home Theater Network What to look for in HDTVs.
• HDTV Forum Your High Definition Forum
• Hi Definition Hardware Useful information on Hi Definition compatible hardware.
• HDTV Consumer Info Information for people unfamiliar with HDTV technology.
• UKHDTV.net UK Resource For HDTV News & Information.
• High Tech Home Magazine Information on Smart-Home related technology including HDTV.
• mariposaHD The world's first original HDTV show made for the Internet. Free 1080i and 720p videos, in WMV HD format, distributed with BitTorrent.
• hdtvtechno

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