By 
CD sales may be on the decline, but there are still many musicians who need masters ready for CD duplication. The format of choice is a DDP which stands for Disk Description Protocol. Everything you need to know is explained here…
Like we used to…
For many years, the standard way to provide a replication-ready master was to create a ‘redbook’ master CD. This was a high quality CDR created on a CD recorder. It worked but there were several drawbacks. The physical media had to be manually checked for errors multiple times throughout the process, from initial creation to final replication. Unfortunately, all CDRs contain errors and can sometimes be rejected by the replication company. Discs are vulnerable to damage and can easily break. Also, it takes extra time and expense to mail them. Trash!
like we do now…
As of 2016, the preferred standard method of shipping a master CD is to provide a ‘DDPi image’ (Disk Description Protocol Image). This format is designed to carry the content of optical discs including CDs. The DDP is a set of files and must contain five parts.
- Audio image (.DAT file)
- DDP Identifier (DDPID)
- DDP Flow Descriptor (DDPMS)
- Subcode descriptor (PQDESCR)
- A text file containing track titles and times is also included.
These files can be stored on a hard drive or sent over the Internet. It is a very robust format that has built-in error checking (MD5 checksum). This ensures that the masters have not been tampered with and will be identical to what ends up on the replicated CD. The total file size will not exceed 750 MB and can be easily sent via a file transfer service or FTP. So there are no shipping costs or delays waiting for the postman. The only drawback of the DDP format is that it cannot be played in a normal CD player. However, you can get a free software player for PC/Mac that will load the DDP file so you can play your CD. You can also check track IDs, CD text, ISRC codes, and spaces between songs. smart stuff.
All CD replication companies must accept the DDP format. If not, I recommend you change companies. This is a strong indication that they are not up to date or reputable. Also, beware of additional charges to provide your teacher as a DDP.