is DVD-Audio ?
DVD-Audio uses the same physical discs as DVD-Video,
but takes advantage of the large disc size to give the
best possible audio quality, rather than video. Whereas
the surround-sound on a DVD-Video is compressed to make
space for the video, on a DVD-Audio you can have full
resolution uncompressed 24-bit 96 kHz sound, plus a
few limited video and menu funtions. DVD-Audio cannot
be played in a normal DVD-Video player, you need a special
DVD-Audio player, or one of the newer "Universal"