Definition: DTV

(Digital TeleVision) Transmitting TV using digital signals. The major DTV standards are ATSC (North America), DVB (Europe) and ISDB (Japan). All three use MPEG-2 video compression and Dolby Digital audio compression. DVB and ISDB also include MPEG audio compression. See ATSC, DVB and ISDB.

The FCC approved ATSC in 1996, and the U.S. switched to digital broadcasting in June 2009 (see digital TV transition). Other countries have also adopted the ATSC format, including Canada, Mexico and South Korea.

A Digital TV or a Set-Top Box
To receive a DTV program requires a digital TV set or a digital set-top box for an analog TV. However, digital TV sets may also have analog inputs for years, because people have huge collections of VHS movies and recordings.

Eighteen DTV Formats
DTV offers 18 digital formats (see table below) starting with Standard Definition (SD), the digital counterpart of the NTSC analog standard, except without snow and ghosts. High Definition (HD) provides 5.1 Dolby Digital Surround Sound and requires a wide screen TV set (16:9) in order to eliminate the letterbox effect.

The numerous options provide the broadcaster with a tradeoff between how many channels can be sent versus channel quality. The more HD channels, the fewer ED and SD channels, and vice versa. See digital TV transition, TV converter box, HDTV, letterbox, NTSC, 8-VSB, interlace and cliff effect.

   p = progressive scan (non-interlaced)
   i = interlaced

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

 HDTV - High Definition TV

  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


 EDTV - Enhanced Definition TV - 480p

  7. 704 x  480   16:9     24p     Rect
  8. 704 x  480   16:9     30p     Rect
  9. 704 x  480   16:9     60p**   Rect

 10. 704 x  480    4:3     24p     Rect
 11. 704 x  480    4:3     30p     Rect
 12. 704 x  480    4:3     60p**   Rect

 13. 640 x  480    4:3     24p     Square
 14. 640 x  480    4:3     30p     Square
 15. 640 x  480    4:3     60p     Square


 SDTV - Standard Definition TV - 480i

 16. 704 x  480   16:9     30i     Rect
 17. 704 x  480    4:3     30i**   Rect
 18. 640 x  480    4:3     30i     Square

 ** most popular formats


  RELATED FORMATS:

  DVD - DV/MiniDV
      720 x 480 x 30 fps (NTSC)
      720 x 576 x 25 fps (PAL/SECAM)
       Only 704 of the 720
        horizontal pixels are visible.

  D1 Broadcast Format
      720 x 486 x 30 fps (NTSC)
      720 x 576 x 25 fps (PAL/SECAM)

SDTV vs. HDTV

The 4:3 aspect ratio on standard TV and computer screens (left) is more square than the 16:9 ratio of wide screen sets (right). (Image courtesy of Intergraph Computer Systems.)

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Definition: DTV