DVD-Audio (also known as DVDA) is a digital format for delivering very high-fidelity audio content on a DVD. DVD-Audio includes no video and should not be confused with video DVDs containing concerts and music videos. The first discs entered the marketplace in 2000. Future occasional DVD-Audio releases are expected and/or have been announced. DVD-Audio is in a format war with Super Audio CD, another format for delivering high-fidelity audio content. Neither has gained much traction in the marketplace. Since media players that can play many formats (including DVD-Audio and SACD) are available, both formats are likely to co-exist (as do Blu-ray and HD DVD).
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http://en.wikipedia.org/wiki/DVD-Audio