[1] Unlike the compact-disc technology it is based on, DDCD was designed exclusively for data, with no audio capabilities.
[2] For a 12 cm disc, it doubles the original 650 MB to 1.3 GB capacity of a CD on recordable (DDCD-R) and rewritable (DDCD-RW) discs by narrowing the track pitch from 1.6 to 1.1 micrometers, and shortening the minimum pit length from 0.833 to 0.623 micrometers.
DDCD was part of a wave of technologies aimed at enhancing the original compact disc, none of which managed to gain widespread adoption.
MultiLevel Recording (ML), developed in 1992 by Optex Corporation, was a proposed technology that never released publicly.
[3] In September 2002, Sanyo announced it had achieved the same result as DDCD using standard CD-Rs with its HD-BURN technology.