Dolby Digital

The most common sound format on the DVD format. Dolby Digital is a compressed sound format and is stored at a variable bit rate. It supports anything up to 7 discrete channels of sound and up to two additional channels for low-frequency bass. Most commonly, Dolby Digital on DVD supports 5.1 channels (left, centre, right, surround left, surround right and sub) but the DVD format can handle any number of channels within the Dolby Digital specification. All DVDs must carry one form of Dolby Digital soundtrack to meet the DVD Forum specifications for the format.