Definition
Universal Music Japan released the Hi-Res CD in 2018, combining two different formats on one single-layer disc. The first is MQA (Mastering Quality Authenticated) and requires MQA compatible hardware or software to play. The second is UHQCD, a high-quality Compact Disc format that is compatible with all Compact Disc players and is already available as a separate format.
MQA (Mastering Quality Authenticated)
An MQA CD can be played on any Compact Disc player and in this case will play Red Book standard audio.
The MQA element of the audio is compressed, and requires an MQA decoder to decompress. This could be a Compact Disc player with a built-in decoder, or a Compact Disc player with a separate decoder. Alternatively, MQA can be played on a computer, though software decoding may not decompress it to its full resolution. MQA is also used for streaming music, and is available through Tidal HiFi.
MQA compression ‘folds’ the high-frequency information existing outside the frequency range of human hearing into the lower frequencies.
UHQ (Ultimate High Quality)
UHQCD discs conform to Red Book standards and are playable in any audio CD player. They don’t contain any more audio information than a standard CD, but it is claimed that a higher-quality manufacturing process and higher quality materials in the reflective layer produces higher precision audio reproduction.
A photopolymer is used instead of standard polycarbonate, since in their liquid state photopolymers achieve better replication of the pits on the CD stamper.
Digital Remaster
