According to AbbreviationFinder.org, HDTV stands for High Definition Television. It is one of the formats that, added to digital television (DTV), is characterized by broadcasting television signals in a digital quality superior to existing systems (PAL, NTSC and SECAM).
HDTV technical details
The HDTV screen uses a 16: 9 aspect ratio. The high resolution of the images (1920 pixels × 1080 lines or 1280 pixels × 720 lines) allows to show much more detail compared to analog or Standard Definition television (720 pixels x 576 lines according to the PAL standard).
The codec used for compression can be MPEG-2, H.264 or wmvhd (Windows Media Video High Definition), although MPEG-2 is currently falling out of date due to its low compression efficiency compared to other codecs. HDTV images are up to 5 times sharper than normal definition television, comparing PAL with higher HDTV resolution.
The 1920×1080 resolution is usually in interlaced mode, to reduce bandwidth demands. The lines are scanned alternately 60 times per second, similarly entangled at 60 Hz in NTSC. This format is called 1080i, or 1080i60.
In areas where the PAL standard at 50 Hz is traditionally used, 1080i50 is used.
Progressive tracking formats with a speed of 60 frames per second are also used. The 1280×720 format in practice is always progressive (refreshing the entire frame each time) and is thus called 720p. Several American television stations currently broadcast in 720p / 60.
Japan had the first working HDTV system, its designs date back to 1979. Japan began broadcasting analog HDTV signals in the early 1990s, using a resolution of 1035 interlaced lines (1035i). The Japanese MUSE system, developed by NHK’s science and technical research laboratories in the 1980s, employing filtering systems to reduce the original source signal and thus decrease the necessary bandwidth. For example, three successive frame elements on a line were actually derived from three separate sweeps. A full camera panorama would lose 50% of the horizontal resolution. Since then, Japan has switched to an ISDB-based digital HDTV system.
The European Commission established a European standard for uncompressed digital HDTV by directive in 1986 (MAC). However, it was never popular with broadcasting stations. It required all high-power satellite broadcasters to use MAC from that year on. Due to technological advancement and the launch of medium power satellites by SES SA, the stations could work without MAC to thus lower transmission costs. HD-MAC (the high definition variant of MAC) was left for intercontinental satellite links. Another cause of the failure of HD-MAC was that it was unrealistic to use 36 Mhz for a high definition signal in terrestrial broadcasts (SDTV uses 6, 7 (VHF) or 8 Mhz (UDF). HD-MAC could only be used by companies of cable and satellite, where there is a greater bandwidth available. Thus, the analog HDTV could not replace the traditional SDTV(terrestrial) PAL / SECAM, making the HD-MAC equipment unattractive to potential consumers. The Barcelona’92 OlympicsThey were recorded in this analog format (4: 3 format, with a definition of 1250 vertical lines). To store them, giant tape tapes the size of a suitcase each were used. Said tapes incorporated handles in their casing to make their transport and handling easier. The HD-MAC standard was abandoned in 1993, and since then all the efforts of the EU and EBU have focused on the DVB (Digital Video Broadcasting) system, which supports both SDTV and HDTV.
For now, many of the countries show limited interest in HDTV. The most common is EDTV using DVB. Although HDTV is still possible with DVB-T, most countries prefer “more channels in a single multiplex”, instead of “a single channel in HDTV”, more common in the USA, Canada, Japan and Australia. As a single HDTV channel would occupy up to four SDTV channels, HDTV is not suitable for terrestrial broadcasting needs in Europe.
Also, some governments want to go digital rather than reallocate VHF frequencies for other uses. A new version of DVB-S (DVB-S2), combined with the H.264 / AVC codec (MPEG-4 Part 10) may be the key to the future of HDTV success in Europe.
In January 2005, EICTA announced plans for an “HD ready” label for equipment that meets certain requirements, including support for 720p and 1080i at 50 and 60Hz. Displays must include YUV and DVI or HDMI interfaces and have a native vertical resolution of 720 lines or more.
The European Commission analyzed the status of 16: 9 broadcasts as well as HDTV in the document The contribution of wide-screen and high definition to the global roll-out of digital television. definition to the global expansion of digital television).
This document states that the previous objectives for the European introduction of HDTV in 1999 (or HD-MAC in 1992) were not achieved because the market focused on digital technologies and services that are easier to implement. Therefore, European consumers never had the opportunity to try HDTV.
Some causes of poor HDTV representation in the EU
- The dominators of the European market thought that HDTV would fail in Europe.
- Broadcasters preferred to focus on cheaper multi-channel SDTV.
- An SDTV screen resolution is better cost effective than an equivalent HDTV.
Commissioners later suggested that some coordination in the EU was required for HDTV services to make it available to all member states.
M6 and TF1 have expressed their intention to broadcast some programs in HD in the near future, however these are not available on the digital terrestrial television service that began in 2005.
TPS, a competitor of Canal Satellite Numérique, also intends to start broadcasting HD in 2005. Terrestrial pay-per-view channels will use H.264 / MPEG-4 AVC from September 2005, to allow premium HDTV content.
The Premiere pay platform will start broadcasting three HD channels in November 2005. These channels will present different content (movies, sports and documentaries). Unlike HD1 and HDe, they will use MPEG6 instead of MPEG2.
Cubans can access the country’s four unique HD channels from the box. The Caribbean Channel, an informative channel par excellence and the experimental HD channel that transmits movies and content in High Definition, as well as Cubavision +, Tele Rebelde (HD3) and Russia Today (HD4)
The BBC already produces some programs (mainly documentaries) in HD for foreign markets, such as the US and Japan. The Corporation intends to produce all of its programs in HD by 2010. The BBC is expected to approve 720p for its progressive scan technology.
There are no plans for HDTV versions of Freeview and Top Up TV for digital terrestrial television services, due to the fact that there is no free bandwidth available. This should change after analog television signals are disconnected, but the date for this disconnection is still being debated.
The payment platform Sky plans to launch its HD satellite services in 2006. It will be limited to some channels and special events. Sky has confirmed that both 720p and 1080i will be available.
Recent reports suggest that Sky will make top-of-the-line sporting events, such as soccer games, available for pubs before the launch of the domestic HD service.
You can almost guarantee that cable TV providers will upgrade to HD as soon as the channels are available.
Japan has pioneered HDTV for decades with an analog implementation. Your old system is not compatible with the new digital standards. In Japan, terrestrial HD broadcasting by ISDB-T started in December 2003. To date, two million HD receivers have already been sold in Japan.
After a long controversy between the government and the broadcasters, the ATSC format was chosen over DVB-T. In 2005, digital services will be available nationwide. They will need to broadcast at least 10 hours each week of HD content during the first year of commercial digital service.
Australia started broadcasting in HD in January 2002 but HD content was not mandatory until August 2003. Most cities in Australia with more than 40,000 inhabitants have at least one DTT channel (for example, in Albany, Western Australia, DTT has been available for almost a year as of May 2005). However, most Australian DTT broadcasters are still experimenting with HDTV broadcasts.
Brazilian universities and government and research institutions are debating the best policies to implement a DTV system in Brazil. Testing is expected in 2005.
The Mexican television company Televisa began making experimental broadcasts on HDTV in the early 1990s in collaboration with the Japanese company NHK. Today there are already some programs on HDTV, but their use is really limited.
During the first half of 2005, at least one cable provider in Mexico City (Cablevision) began offering five HDTV channels to subscribers who purchase a digital video recorder (DVR).
HDTV can be recorded on D-VHS (Data-VHS), W-VHS, or on a digital video recorder that supports HDTV such as the TiVo offered by DirecTV or the DVR 921 and DVR 942 offered by DISH Network. Currently, the only recording option in the United States is D-VHS. D-VHS records in digital form at a speed of 28.2 Mb on any VHS tape, requiring a FireWire (IEEE 1394) digital transport to couple the compressed MPEG-2 frame from the modulator device to the recorder.
Unfortunately, the enormous data storage capacity required to store uncompressed data makes it unlikely that an uncompressed storage option will appear on the market for years to come. MPEG-2 real – time compression of an uncompressed HDTV signal is also extremely expensive, making it prohibitive for the market, although its cost is predicted to drop in a few years (although this is actually more in the interest of consumers. HD video cameras than HDTV recorders). In addition, analog tape recorders with sufficient bandwidth for storing analog HD signals such as W-VHS recorders are now discontinued in the consumer market and are expensive and hard to come by in the aftermarket.