High Definition Television, or HDTV, is one of the formats used in digital television (DTV) broadcasting.

The HDTV screen uses a 16:9 aspect ratio (the 4:3 aspect ratio is sometimes used). The high resolution images (1920 pixels × 1080 lines or 1280 pixels × 720 lines) allow much more detail to be shown. The images are expected to be at least 6 times as sharp as standard definition television or NTSC or PAL standard analog television. Like NTSC and PAL, most 1920x1080 broadcasts are to use interlacing to reduce bandwidth demands (giving the format the alternate name 1080i), a progressive-scan format is available, but reduces the number of frames per second to 24 (1080p24), in the future, MPEG-2 Or MPEG-? could create a 1080p with 30 to 60 frames per second (1080p30) to (1080p60); 1280x720 will be broadcast in progressive-scan (with the entire frame refreshed each time) and is thus termed 720p. The refresh rate can be any of 24, 30 or 60 pictures per second.

It has been technically possible to create higher-resolution televisions for many years—for instance, computer monitors have been able to display high-resolution images with superior color and refresh rates since the 1980s. Japan began broadcasting analogue HDTV signals in the early 1990s using an interlaced resolution of 1035 lines (1035i)(more details anyone).

Broadcasts of HDTV elsewhere as of January 2004

  • Japan terrestrial broadcast of HD via ISDB-T started December of 2003. It is reported that one million HD receivers have been sold in Japan already.
  • Australia started HD broadcasting January of 2002 but only in August of 2003 was HD content mandated. Since August sales of DTV receivers in Australia have picked up.

Many countries show limited interest (most of Europe has instead gone to widescreen
Standard definition television)though satellite delivery of HD started in Europe January 1st 2004.

Interestingly, Australia seems to be the only true believer in HDTV. It is the only country that has mandated HD and the amount of content that broadcasters are obligated to broadcast.

Because HDTV requires more broadcast spectrum, it has been the topic of great political controversy in the United States. According to FCC rules, all television broadcasting in the United States by current full power broadcasters on channels 2-51 will by 2006 be digital, thereby rendering reception by all current analog receivers via antenna over the air reception obsolete. Current analog TV sets would still work with cable or satellite service or with a converter box that would convert digital OTA signals to analog. The FCC ruled in August 2002 that all TV sets with screens of at least 36 inches must have digital tuners by July 2004, while the requirement for smaller sets would be phased in over the following three years.

The FCC requirement is that manufactureres include a digital 8-VSB tuner in any TV set that already has an analog receiver in it. The consumer can still buy a monitor or TV without any tuner. Consumers thereby can avoid the cost of a digital over the air receiver if they only want to hook up to cable or satellite or if they want to buy a better over the air stand alone receiver than that which a TV manufacturer might put in a "TV" set.

Since tuners may get better and things change in the receiver and modulation area faster in our rapidly changing tech world it may be prudent to not buy an integrated "TV" set. That is just buy a monitor or display device and connect it to a stand alone receiver, cable or satellite STB.

Many have expressed doubts as to whether this will actually occur. TV monitors capable of showing HDTV pictures have started to appear on the marketplace, but they are quite expensive (upwards of 2000 USD as of 2002), and are only available in large screen sizes, where the extra resolution of HDTV makes the greatest difference. For more compact televisions, the benefits are considerably more marginal.

Satellite television companies in the USA, such as Dish Network, started to carry HD programming in 2002. Some cable television companies, such as Comcast, started to do the same in 2003. As of July 2003, HD programming is carried by all major television networks (except Fox which plans to go HD in mid 2004) including ABC, CBS, NBC, PBS and The WB as well as other cable/satellite channels including Discovery HD Theater, HBO, HDNet, DirecTV HD PPV, Showtime HDTV and INHD. HD TV programming is very time consuming. According to PBS, it took 1000 hours to produce a three hour program. PBS only produces about 10 hours of HD programming per month as of July 2003. As of July 2003, ABC provides the most hours of HD programming per day among other non-cable networks. In Canada, on November 22, 2003, CBC had their first broadcast in HD, Bell ExpressVu, a Canadian satellite company has TSN HD and Discovery HD(Canadian Edition). The Canadian Discovery HD Channel has commercials and is sponsored By Franklin Templeton Investments.

In an attempt to provide a bitrate-compatible high-definition format for high-definition DVDs, Microsoft introduced into their Windows Media 9 Series codec the ability to compress a high-definition bitstream into the same space as a conventional NTSC bitstream (approximately 5 to 9 megabits per second). 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 requires a significant amount of processing power to encode and decode. The only commercially available movie that uses this codec is the Terminator 2: Extreme Edition DVD.

Other similar codecs are in contention such as VP6 from ON2 and AVC. VP6 has been chosen by China for both digital TV and DVD production. This is as a result of China wanting to avoid royalties on WM9 or AVC, VP6 has offered a one time $2 per device and no royalties on usage. With China starting to dominate manufacturing of TV and DVD units their choice of standards becomes more central for everyone. VP6 is also considered by many to be a superior codec.

One of the reasons for the FCC's push for digital transmission is the desire to auction off Part of the UHF spectrum, channels #52 through #69, for other two way and one way fixed and mobile services. This could include digital mobile TV broadcasting.

Samsung launched the world's first HD-DVD player (it will only play MPEG-2, not Windows Media 9). A direct digital up-converting chip allows a fully digital HD signal to be transfered through the DVI standard.

Consumers' reaction to the current (2003) offering of HDTV is mixed. Some early adoptors of the technology are very excited about the video and audio quality. Some other consumers are disppointed at the limited availablity of HD programming. In addition, the picture quality of HDTV can only be as good as the recorded source of the programs. Most of the movies broadcast on HD channels such as HBO HD and Showtime HD are similar to DVD quality probably because the channels use DVD as their movie source. Only when the programs were produced in HD, such as in live football games and PBS documentaries and other newly produced primetime shows, the true quality of HDTV shines through. As of 2003, only a small portion of the daily HDTV programmings maximize their full potential. Consumers who don't understand the limitations are often disappointed and regret buying into HDTV too soon.