Dolby Audio Code 3 (referred to as AC-3, but the more popular name is Dolby Digital) is an audio coding format developed for HDTV (high-definition television) applications, it will 5 full frequency bands (3Hz ~ 20000Hz) The audio track and a low frequency band (3Hz ~ 120Hz) audio track are encoded into a data stream through lossy compression.
It uses a compression algorithm that deletes some sound details that are not easily heard by the human ear, enabling a 10: 1 compression ratio. The Dolby Digital standard has been widely used in the film industry. It can be seen on most DVDs, and almost all DVD players can support this standard.