Definition: An audio technology used on many movie DVDs to provide sound. Many DVDs make the audio available in what is called Dolby Digital 5.1, which is capable of providing high-quality sound, although to get the full effect you generally need to have five speakers and a device known as an AV receiver, that is, you must have the audio components of a home theater system. Nevertheless, you will still get reasonably good audio quality if you listen through the speakers built into a TV set because the DVD player will automatically remix the sound for whatever speakers are available. On the audio menu of some movie DVDs, you can choose between Dolby Digital 5.1 and Dolby Digital 2.0. Most TVs come with two built-in speakers, and if you're going to listen through them, choosing the 2.0 option should get you slightly better sound.