What is HDTV (High Definition Television)?

HDTV (High Definition Television) is one of the formats added to digital television (DTV), characterized by broadcasting television signals in a digital quality superior to existing systems (PAL, NTSC, and SECAM).

What is HDTV (High Definition Television)?

HDTV Features and Usage in Some Countries

The HDTV screen uses a 16:9 aspect ratio and the high resolution of the images allows much more detail to be shown than analog or standard-definition television.

The codec used for compression, MPEG-2, H.264, or WMV-HD (Windows Media Video High Definition) can be used, but MPEG-2 offers lower compression efficiency compared to other codecs.

Television images are up to 5 times sharper than normal television, comparing its higher resolution with PAL, and the 1920×1080 resolution is typically in interlaced mode to reduce bandwidth.

Lines are scanned 60 times per second alternately, as in NTSC, and this format is called 1080i or 1080i60.

Conventionally, 1080i50 is used in areas where the PAL standard is used at 50 Hz, and progressive monitoring formats at 60 frames per second are also used.

In practice, the 1280×720 format is always good and hence it is called 720p. Several American television stations are currently broadcasting in 720p/60.

Old Systems

   MUSE

Japan had the first HD TV system, whose designs date back to 1979. In the early 1990s, it began broadcasting analog signals using a 1035 interlaced line (1035i) resolution.

Developed in the 1980s by NHK’s science and technical research laboratories, the Japanese MUSE system used filtering systems to reduce the original source signal and thus reduce the required bandwidth.

For example, three successive frame elements on a line are actually created with three separate hatches.

Japan switched to an ISDB-based digital HD TV system as a full camera panorama lost 50% of the horizontal resolution.

   HD-MAC

The European Commission created a European standard for uncompressed digital HD TV with the MAC directive in 1986.

However, it was never popular with broadcast stations, but from then on all high power satellite broadcasters had to use MAC.

With the technological advancement and the launch of medium power satellites by SES Astra, the stations operated without MAC, reducing transmission costs. Later, HD-MAC was used for intercontinental satellite connections.

The reason for the failure of HD-MAC was that it did not use the 36 Mhz frequency for a high definition signal in terrestrial broadcasts.

HD-MAC can also be used by cable and satellite companies where higher bandwidth is available.

Therefore, analog HD television cannot replace traditional PAL/SECAM SDTV, making HD-MAC preferable.

The HD-MAC standard was discontinued in 1993, and since then all EU and EBU developments have been on DVB (Digital Video Broadcasting) technology, which supports both SDTV and HDTV.

New Systems

   Europe

It is the most widely used EDTV with DVB features in Europe.

While HD televisions are still used with DVB-T, countries such as the US, Canada, Japan, and Australia prefer more channels in a single multiplex rather than a single channel in HDTV.

HD TV is not suitable for terrestrial broadcasting needs in Europe as a single HDTV channel will replace four SDTV channels.

Some governments wanted to switch to digital rather than reallocating VHF frequencies for other purposes.

A new version of DVB-S (DVB-S2) combined with the H.264/AVC codec has greatly increased the use of HDTV in Europe.

EICTA announced HD Ready technology for equipment that meets certain requirements, including support for 720p and 1080i at 50 and 60 Hz.

Therefore, screens must include YUV, DVI, or HDMI interfaces and have a native vertical resolution of 720 lines or more.

   European Union

The European Union studied the global use of digital broadcasts in 16: 9 broadcast status as well as HD document for widescreen and high definition.

European consumers did not have the opportunity to try HDTV, as this document stated that the previous targets for the introduction of HDTV in Europe in 1999, the market did not focus on easier-to-implement digital technologies and services.

The main reasons for this failure are that the dominants of the European market think HDTV will fail in Europe, broadcasters prefer the cheaper multi-channel SDTV, and SDTV is more cost-effective.

   Other Countries

In France, M6 and TF1 had announced plans to broadcast some programs in HD, but did not use it in digital terrestrial television services but planned to use H.264/MPEG-4 AVC to enable Premium content.

Germany started streaming three HD channels in November 2005 with the Premiere payment platform. Initially, this channel content included movies, sports events, and various documentaries.

Cubans had the right to access the country’s two unique HD channels out of the box.

In the UK, the BBC has already broadcast some programs in HD, such as documentaries, for foreign markets such as the USA and Japan. The BBC company then started broadcasting all of its programs in HD.

Because there is no free bandwidth available, paid platforms such as Freeview are available for digital terrestrial broadcasts.

Later, Sky, the payment platform, launched HD satellite services.

Japan pioneered HDTV for years with an analog application, but its old systems were not compatible with newer systems. In addition, ISDB-T’s terrestrial HD broadcast began in December 2003, and two million HD receivers were sold.

In South Korea, after discussions between the government and broadcasters, the ATSC format began to be used instead of DVB-T.

Australia started broadcasting in HD in January 2002, and most cities with a population of over 40,000 had at least one DTT channel.

Mexican television company Televisa, together with the Japanese company NHK, began conducting experimental broadcasts on HDTV in the early 1990s.

DVR (Digital Video Recorder)

Its broadcasts can be recorded on a digital video recorder that supports HDTV. An example of a DVR device in the United States is D-VHS.

D-VHS records in digital format at 28.2 Mb to any VHS tape that requires a FireWire (IEEE 1394) digital transmission to connect the compressed MPEG-2 frame from the modulator device to the recorder.

The enormous data storage capacity required to store uncompressed data can be considered as a disadvantage. Therefore, MPEG-2 real-time compression is not preferred as it is expensive.

In addition, analog tape recorders with sufficient bandwidth to store analog HD signals, such as W-VHS recorders, were deprecated.

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