What It Means: HD
The world of modern video is filled with confusing terms and unwieldy acronyms. Our glossary will help you sort it all out.
The proportions (width:height) of the viewing area on a monitor or a television screen. HD has a wide-screen, 16:9 ratio. SD has a narrower ratio—4:3.
ATSC: A digital-broadcasting standard developed by the Advanced Television System Committee (also refers to DTV and HDTV standards).
Digital TV (DTV): A television signal transmitted as digital information. HD video is digital, but not all digital broadcasts are HD.
Dolby Digital: Six-channel digital-audio standard, also called AC-3 or Digi-tal 5.1.
Enhanced Definition TV (EDTV): A progressive SD television that accepts the progressive output of some DVD players. Usually, these TVs also have a de-interlacer built-in. They are not HDTVs.
HDMI: High Definition Multimedia Interface—a digital connector.
HDTV-Ready: A TV that can display HD video if a separate HD decoder box is attached.
MPEG-2: Moving Picture Experts Group 2. A video-compression format used to condense HD and SD video, for smaller data rates in DVDs and broadcasting.
Terrestrial Broadcast: Traditional over-the-air broadcast.