High Definition Compatible Digital (HDCD) is a proprietary audio encode-decode process that claims to provide increased dynamic range over that of standard Compact Disc Digital Audio, while retaining backward compatibility with existing compact disc players.

HDCD is a favorite among artists who have a preference for high quality sound, such as Neil Young, the Beach Boys and the Grateful Dead—all of whom have multiple CD titles (new and archival) in their catalogs mastered in this process.

[6] HDCD technology was developed between 1986 and 1991 by "Prof." Keith O. Johnson and Michael "Pflash" Pflaumer of Pacific Microsonics Inc.

It was made publicly available as HDCD-enabled audio CDs (often identifiable by the HDCD logo printed on the back cover) in 1995.

Since version 9 of Microsoft's Windows Media Player (WMP) HDCD enabled CDs can be played on personal computers fitted with a 24-bit sound card.

[17] Illustrate's dBpoweramp Music Converter, a Windows GUI program, has an HDCD DSP effect that acts as a front-end to the utility listed above.