Glossary of Terms

The process of manufacturing a CD where discs are created through injection molding polycarbonate plastic.  These 'green discs' are then aluminum plated and another 'top coat' of plastic is applied for the label.  Generally, a batch of one thousand discs is the smallest quantity that a replication plant can cost-effectively offer.  This process yields a very high-quality, professional product, and is not to be confused with duplication which is of lesser quality.
A glass master is made at the replication plant in a specialized clean room, not at the mastering studio.  A glass disc, 240mm in diameter and 6mm thick,  is used as a substrate to 'etch' the image of the digital data as pits and lands that will ultimately be the ones and zeroes that the CD player will read as audio information.  Some audiophiles insist on real-time (1x) creation of a glass master for highest audio quality.

DDP

DDP stands for Disc Description Protocol.  It is a format used to send technical information about the structure and contents of optical discs (CD, DVD, HD-DVD) to a replication plant.  It was developed by Doug Carson and Associates, Inc. in 1989 and DCA, Inc. still owns the format.  It is the industry standard for most optical media premasters.   In the past, DDP images have been delivered on DLT (Digital Linear Tape) or Exabyte (another digital tape technology), but can now also be sent over FTP (File Transfer Protocol) or on another digital storage medium.

A master is a data storage device that transports the final recorded product to the replication plant.  The two most common formats today are Red Book PQ-Masters and DDP Masters.
The last creative step in the recording process and the first technical step in the replication process.

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