Derived from the Dolby Stereo technology used in movie theaters, Dolby Surround was introduced in the early 1980s for video soundtracks, audio cassettes, CDs, TV broadcasts, video games and PC ...

Dolby Stereo was later renamed the Dolby analog format. See Dolby Surround and Dolby Digital. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

This evolved into Dolby Pro Logic, which could intelligently extract 5.1 surround sound from a regular stereo soundtrack.