High definition television

The high definition television in English for TV H igh D efinition not to confuse with the label HDTV (in English H igh D efinition Television of), is characterized for television with the general direction like a unit Audiovisuel High-definition primarily by:

  • diffusion HD like TNT - HD
  • the Television HD with the label HD Ready
  • the read/write drive of disc HD to the label HDTV
  • video supports HD Blu-ray Disc and HD-DVD.
In light, the logo HDTV will be posted on the readers and recording video of disc while the logo HD Ready will appear on televisions, it misses diffusion HD and support HD so that the tvhd definition is complete.

To date there does not exist Logo nor of label TVHD.

Why change the definition of the television sets, the support and the diffusion?

Technological advances

The progress made as regards video and audio compression of techniques of diffusion allows the diffusion of television channels in high-definition but also of the equipment and of supports Audiovisuel.

The limitation for the general public comes especially from the cost of screens LCD having a horizontal definition of 768 lines. The marketed screens carrying the label HD Ready offer obligatorily a minimal definition of 720 vertical lines is twice more pixels than standard television. The screens Full HD (1080p) post a definition of 1080 vertical lines (either 1920x1080 pixels in format 16/9) or 5 times more pixels than standard television.

Technologies of posting current Full HD are: CRT (cathode tubes) - Tri LCD - DMD - Plasma - SED (technology approaching the CRT) - OLED - SXRD (Sony) - Dila (JVC)

The various formats high-definition

One directs in Europe today towards two labelized standards HD Ready: 1080 lines of 1920 points interlaced (1080i) and 720 lines of 1280 points (720p), the number of Pixel S is doubled compared to the SDTV. the Full HD correspondent with 1080 lines of 1920 points into progressive.

The principal formats of image usable are the following:

  • 720p : 1280 X 720 to 50 and 60 progressive Hz in
  • 1080i: 1920 X 1080 to 50 and 60 Hz in Interlaced
  • 1080p: 1920 X 1080 in progressive

Sizes of television sets

While considering that the Resolving power of the eye is of a Minute of arc (0°01'), the ideal distance to look at a traditional Téléviseur 4/3 (576 lines and 720 Pixel S by line) is of approximately four times the diagonal of the screen (either a distance of 2 meters for a Téléviseur of 50 centimetres diagonal); for one the 16/9 ideal distance is of approximately three times the diagonal.

The largest television sets reach today more than one meter of diagonal, but the distance to which one looks at them appreciably remainder the same one. If one wants to preserve the same quality of image with a television set of 1 meter of diagonal located at the same distance, it is necessary to increase the definition of the image.

Quality of the image of diffusions

  • Since June 2005, Canal+ diffuses a program demonstration HD which became a regular offer since 2006.
  • Since the beginning of 2006, diffuse TPS of programs HD on chains TPS Star (permanently), TF1 and M6 (punctually).
  • the operator of satellites Astra diffuses also a channel of demonstration HD.
  • the satellite Hot-Bird diffuses a program test of HD Forum , consortium of firms around concept HD.

In a near future, the Digital terrestrial television should emit certain chains in HD, by using a compression MPEG-4 AVC (still called MPEG-4 leaves 10 or H.264). The first tests took place in June 2006 at the time of the international ones of tennis of Roland Garros, diffused in experiments on Paris, Lyon and Marseilles. This world big first was succeeded by France Televisions which during two weeks fed on transmitters TNT of these 3 cities in MPEG4 HD 24/24 H of these programs resulting from International from France from Roland Garros but also on the networks from TV on ADSL of the two operators who are FREE and Orange always in MPEG 4 HD.

Quality of the image of the support

One finds on Internet of many small films, of the bands advertisements in particular, with the format MPEG-4 or the derived formats: DivX, or Windows Media Video HD. The high compression of these formats makes it possible to obtain video HD (1920x1080 or 1280x720) of good quality with a flow of 8 or 9 Mbit/s, are the current flow of the MPEG2 used for the video DVD.

See too

Other formats HD are also available such as: 720p - 1080i - 1080p

Bonds

  • Any knowledge on TV HD
  • High-definition - the choice of Europe, technical review of UER
  • TV HD: why? How?

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