Dolby E

Dolby E is a codec from Dolby Laboratories that is used to transport up to 8 channels of audio across AES-3 cabling (AES-3 is the professional version of SPDIF). It is carried in a SMPTE-337M data burst. Dolby E also carries metadata such as downmixing information which is intended to be passed through to the final distribution encoder.

Frame Structure

Dolby E is designed to match up with video frames to allow for easy cutting. Guard Bands are also present at the beginning and the end of the frame to reduce the risk of bad splicing causing problems.

There are 3 input bit depths of Dolby E: 16-bit, 20-bit and 24-bit. It is unknown whether 24-bit exists in the wild. 16-bit mode has a maximum of 6 channels, 20-bit mode has a maximum of 8 channels and 24-bit has an unknown number of channels.

Transforms

Dolby E uses a slightly edited MDCT:

Decoder/Encoder

A free trial of a software Dolby E encoder and decoder that supports encoding of 16-bit and 20-bit modes and decoding of 16-bit, 20-bit and possibly 24-bit is available from http://www.neyrinck.com. However it requires Pace iLok to run, which features kernel level anti-debugging.