Dolby Surround

Dolby® Surround is the consumer version of the original Dolby multichannel analog film sound format (Dolby analog and Dolby SR [Spectral Recording]). When a Dolby Surround soundtrack is produced, four channels of audio information—Left, Center, Right, and Mono surround—are matrix-encoded onto two audio tracks. These two tracks are then carried on stereo program sources such as videotapes and TV broadcasts into the home, where they can be decoded by Dolby Pro Logic® to recreate the original four-channel surround sound experience.

A result of Dolby's expertise in matrix surround processing, Dolby Pro Logic was the foundation for multichannel home theater, and was the reference decoder for creating the surround sound audio tracks in thousands of commercially available videocassettes, laser discs, DVDs, and television programs.

With the introduction of the Dolby Digital multichannel film sound format, Dolby Digital has replaced Dolby Surround as the preferred technology to deliver multichannel audio to consumers via DVD-Video, digital television, and games. However, every Dolby Digital decoder also provides a Dolby Pro Logic-compatible stereo signal on its analog outputs. See Dolby Digital for additional details.