Dolby Laboratories DP564 - Manual (Page 71)

DP564 Multichannel Audio Decoder
A-1
Appendix A
Metadata
Note: This appendix was originally written for users of Dolby ®
E products that assign
metadata parameter values. The DP564, as a decoder, simply uses the metadata
parameters included in a Dolby Digital bitstream. However, the detailed
explanation of metadata concepts and parameters may prove useful to you.
Metadata provides unprecedented capability for content producers to deliver the
highest quality audio to consumers in a range of listening environments. It also
provides choices that allow consumers to adjust their settings to best suit their
listening environments.
In this appendix, we first discuss the concept of metadata:
• Metadata overview
We then discuss the three factors controlled by metadata that most directly affect the
consumer’s experience:
• Dialogue level
• Dynamic range control (DRC)
• Downmixing
We then define each of the adjustable parameters, and provide sample combinations:
• Individual parameters
• Metadata combinations
A.1 Metadata Overview
Dolby Digital and Dolby E are both bit-rate reduction technologies that use metadata
to describe the encoded multichannel audio. In normal operation the encoded audio
and metadata are carried together as a data stream on two regular digital audio
channels (AES/EBU or S/PDIF). Metadata is carried in the Dolby Digital or Dolby E
bitstream, describing the encoded audio and conveying information that precisely
controls downstream encoders and decoders. Metadata allows content providers
unprecedented control over how original program material is reproduced in the home.
Dolby Digital is a transmission bitstream (sometimes called an emission bitstream)
intended for delivery to the consumer. It consists of a single encoded program of up
to six channels described by one metadata stream. The consumer’s Dolby Digital