DVD-Audio is not the same as the audio formats used for the soundtracks in DVD movies, which are various lossy formats. It is a separate audio-only standard that supports very high digital audio resolutions, up to 24 bits depth/192 kHz sampling rate for two-channel stereo, and up to 24/96 (uncompressed) per channel for 5.1 surround. In comparison, CD-Audio is 16/44.1, and is two-channel stereo only.

An increasing number of DVD players support DVD-Audio, even in car hi-fi. With DVD-Audio you can create your own super-high fidelity disks, or stuff several CD's worth onto a single DVD, or enjoy genuine 6-discrete-channel surround.

To create your own DVD-Audio disks you need:

• Ordinary DVD blanks
• Ordinary computer DVD burner
• Audio tracks in FLAC, WAV, or AIFF formats
• DVD-Audio authoring software that converts your tracks to the correct DVD-Audio format
• A player that supports DVD-Audio playback

Wikipedia has a decent article about DVD-Audio, and there are even a few commercially-produced DVD-A music disks you can purchase.