High Definition Compatible Digital (HDCD) is a patented encode/decode process
for delivering the full richness and detail of the original microphone feed on
compact discs (CD's) and DVD-Audio. HDCD has been used in the recording
of more than 5,000 CD titles, which include more than 250 Billboard Top 200
recordings and more than 175 Grammy nominations, and account for more
than 300 million CD's sold.

HDCD-encoded CD's sound better because they are encoded with 20 bits of real
musical information, as compared with 16 bits for all other CD's. HDCD overcomes
the limitation of the 16-bit CD format by using a sophisticated system to encode the
additional 4 bits onto the CD while remaining completely compatible with the
existing CD format. HDCD provides more dynamic range, a more-focused 3-D
soundstage, and extremely natural vocal and musical timbre. With HDCD,
you get the body, depth, and emotion of the original performance - not flat
digital imitation.

HDCD uses a 20-bit master instead of 16 bits and stores the additional data in
a subchannel that is processed on HDCD-equipped players. Some of the
additional data are included in the regular recording which is audible on
standard CD players. The format remains compatible with the traditional
audio CD, and non-HDCD players can play HDCD discs as if they were regular CDs.