Dolby Digital (redirected from AC 3)

Dolby Digital

A digital audio encoding system from Dolby used in movie and home theaters. First used in 1995, Dolby Digital employs Dolby's AC-3 (Audio Coding-3) coding and compression technology and is the standard for DVD-Video and HDTV.

5.1 Channels
Dolby Digital provides five discrete channels of audio plus a subwoofer channel for low frequency effects (the "1" in the 5.1). The five channels are front left, right and center and surround left and right.

6.1 Channels - Dolby Digital Surround EX
Co-developed with Lucasfilm THX, Dolby Digital Surround EX adds a rear center speaker. The first film to use this enhanced version of Dolby Digital was "Star Wars: Episode I - The Phantom Menace," in 1999.

6.1 & 7.1 Channels - Dolby Digital Plus
Part of the Blu-ray disc specification, Dolby Digital Plus supports 6.1 and 7.1 speaker configurations at significantly higher bit rates. Also called "DD+" and "Enhanced AC-3" (E-AC-3), these formats cannot be played with standard AC-3 codecs. See Blu-ray.