DDP File in Mastering

DDP stands for Disc Description Protocol also known as DDPi (image) or DDP file set.

 DDP is recommended by mastering studios. It is a delivery format that ensures an error protected audio material supplied by the mastering studio and suited for CD/DVD replication.

A DDP file contains audio as an image file with 3 additional sub-files that carry all other necessary disc information.

CraftLabMastering includes an additional checking file to verify data accuracy between transfers.

Nowadays, DDP is becoming the audio industry for optical discs replication due to their reliability and the robust data error (if any) correction algorithms.

Audio CDs on the other hand, introduce far more errors on burning and playback with less reliable error correction.

There are two different sources from which CD Track information is obtained.

For less confusion, please note:

CD-Text shown on some CD-Players is inserted within the metadata (PQ codes) while burning a Red Book CD. Specific software is used to insert this information (CD-Text, ISCR Codes, Track Start/End…).

Since its release in 1996, CD-Text has been adopted (slowly) but not by all CD Players or CD-ROM manufacturers.

CD Track information shown on iTunes, Windows Media Player or other software media players is linked to an Online Database Server from which any user can upload or download information regarding an Album (Track titles, Genre, Artwork, Comments, lyrics...)

CraftLabMastering offers CD-Text on RedBook CDs (or DDPi)

Dither is a random low-level noise (similar to a hiss) added to the signal to trim digital distortion known as quantization error. Dither must be used when reducing wordlengths (mainly down to 16-bit).

There are different algorithms to accomplish dither but they all fall into two flavors:

• Flat-shaped dither which is similar to white noise.
• Noise-shaped dither which adds the noise to an unheard (by a human) audio band.

All dither sounds different and every music demands specific dither type. Dither must be added once and at the end of the signal chain. Therefore it is the Mastering Engineer's responsibility to insert and choose the right dither type.

Try it yourself:

• Start with a 32-bit sine wave.
• Truncate it to 8-bit using dither.
• Notice the added hiss (dither). It is gentle to our ear.
• Truncate the 32-bit to 8-bit without adding dither.
• Notice the unnatural digital distortion. It is unpleasant to our ear.

It is arguable that 8-bit file is a low-quality sound therefore with a 16-bit Redbook CD there is no need to dither. However, with some kind of music we clearly hear the difference (dynamic and low-level tracks for example), and generally on the fade outs (with any kind of music). 

Dither in Mastering is our friend while digital distortion is not!