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Definition: HDTV


(High Definition TV) HDTV is the high-resolution part of the digital TV standards (see DTV). HDTV may refer to the resolutions or to the TV set, but HD always refers to the resolutions, which were the highest prior to 4K Ultra HD (see 4K TV). See SDTV.

Convert Up and Down
Using algorithms to fill in the missing lines, HDTV sets upconvert standard definition (SD) content, such as old movies or DVDs, to the HD resolution the HDTV supports (see table below). HD programs are broadcast in 720p and 1080i, and 720p HDTVs downconvert 1080i broadcasts to 720p. In addition, HDTVs provide numerous zoom and stretch modes to accommodate SD resolutions (see HDTV display modes). See HD formats. For TV types, see flat panel TV, rear-projection TV and front-projection TV.

 HD - HIGH DEFINITION TV (HDTV)

                         Frame
   Resolution    Aspect  Rate   Pixel
   Horiz x Vert  Ratio   (fps)  Shape

 1. 1920 x 1080   16:9    24p   Square
 2. 1920 x 1080   16:9    30p   Square
 3. 1920 x 1080   16:9    30i   Square

 4. 1280 x  720   16:9    24p   Square
 5. 1280 x  720   16:9    30p   Square
 6. 1280 x  720   16:9    60p   Square

  p = progressive scan
  i = interlaced



HD Ready, Capable, Built In or Integrated
An "HD Ready" or "HD Capable" TV set means that it can display 720 progressive lines of resolution (720p) at minimum and can scale up lower and scale down higher-resolution signals to fit the screen. HD Ready requires an HD set-top box from the cable or satellite company to receive HD programs.

"HD Built In" or "integrated HDTV" refers to a TV with a built-in HD tuner for capturing HD broadcasts over the air.

HD Has Been Around Awhile
Since the turn of the century, consumers have become familiar with high definition TV; however, HD was available years before that. Japan experimented with HD formats in the 1970s and 1980s and was the first to broadcast an 1125-line signal for expensive, large-screen TV sets in the early 1990s. Both Japan and Europe's initial HD formats were analog.

For many years in the U.S., various analog and digital HD formats were used to shoot closed circuit presentations for corporate board rooms, trade shows and similar events. See interlace, deinterlace, DTV, letterbox, HD-DVD and aspect ratio.




Less Letterbox on HDTV
When a wide-screen movie is rendered without modification on an SD screen (left), black bars are displayed at the top and bottom (see letterbox and pan & scan). (Image courtesy of Intergraph Computer Systems.)