Dolby Surround is the earliest consumer version of Dolby's multichannel analog film sound decoding format Dolby Stereo. It was introduced to the public in 1982 during the time home video recording formats (such as Betamax and VHS) were introducing Stereo and HiFi capability. The term Dolby Surround is used so as not to confuse theater surround (Dolby SR, which has four channels of audio) with home stereo, which has only two. Dolby Surround is the earliest domestic version of theatrical Dolby Stereo. The term also applies to the encoding of material in this sound format.