Dolby Laboratories DP570 Specifications download pdf (Page 8)

Standards and Practices for Authoring Dolby

Digital and Dolby E Bitstreams

the sound of the decoded program based upon a consumer’s listening conditions. It is

therefore vitally important to monitor the effects of metadata while mastering a Dolby

Digital data stream.

Metadata provides the tools necessary for audio programs to be reproduced accurately

and artistically in many different listening situations from full-blown home theaters to

in-flight entertainment, regardless of the number of speaker channels, quality of

playback equipment, or relative ambient noise level. While an engineer or content

producer takes great care in providing the highest quality audio possible within their

program, they have no control over the vast array of consumer electronics or listening

environments that will attempt to reproduce the original soundtrack. Metadata

provides the engineer or content producer greater control over how their work is

reproduced and enjoyed in almost every conceivable listening environment.

3.3 The Three Ds: Dialogue Normalization, Dynamic Range

Control, and Downmixing

Metadata provides a number of key parameters that are specifically designed to

control the sound of the program delivered to the consumer, depending upon

selections made at the consumer’s decoder that reflect their unique listening

environment. These metadata parameters are known generally as Dialogue

Normalization, Dynamic Range Control, and Downmixing.

Note: Rather than a single metadata parameter, the function of Downmixing within

the consumer’s Dolby Digital decoder is controlled by several specific

metadata parameters, and, as with the other two Ds, care must be taken in

monitoring and selecting these metadata parameters.

The engineer is ultimately responsible for optimizing the multichannel mix for best

reproduction in the optimal listening environment so care should be taken to ensure

that less optimal listening environments consisting of fewer speaker channels or high

ambient noise levels are supported. For example, enjoyment of a DVD, game console,

or digital television program should not be limited to only those consumers with full-

blown home theater systems. Dolby Digital and metadata together provide a method to

achieve the highest quality audio reproduction without compromising the integrity of

the original encoded audio, regardless of the number of speaker channels, relative

ambient noise levels, or quality of equipment in a playback system.

3.4 Dialogue Normalization

The Dialogue Normalization (also known as Dialogue Level or Dialnorm) parameter

within the Dolby Digital stream provides a relative value to the home decoder or set-

top box that adjusts the audio to a predetermined replay loudness level. This value

aids in level matching between program content and media types (i.e., DVD, DTV,

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Dolby Laboratories DP570 Specifications Page 8