Compact disc encoding/decoding scheme developed by Pacific Microsonics with the goal of improving on the sound of traditional CDs. HDCD discs are encoded with special information that can only be taken advantage of by a CD player or digital-to-analog converter with a Pacific Microsonics HDCD decoder microchip. HDCD discs are playable on normal, non-HDCD, CD players and normal CDs can be played on CD players using HDCD technology. However, HDCD discs played on a normal CD player will not benefit from the HDCD encode/decode process (that requires a HDCD decoder). The HDCD technology is meant to give extra extension to normal CDs and provide more sound information resulting in superior sound quality and “definition.”