- Dolby Multichannel Audio Tool User's Manual

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92 Dolby

DP570 Multichannel Audio Tool User’s Manual

A Guide to Dolby Metadata

ThereareseparatemetadataparametersthatgoverntheLo/RoandLt/Rtdownmixes.

Certainmetadataparametersallowtheengineertoselecthowthestereodownmixis

constructedandwhichstereoanalogsignalispreferred,butLt/Rtisthedefaultselection

inallconsumerdecoders.SeeParameterDefinitionsonpage 92 forthe

definitionof

individualparameters.

Duringdownmixing,aswehaveseen,theadjustmentofDynamicRangeControl

parametersislimited.Broadlyspeaking,thestereooutputsusetheLinemodecompression

profilewhilethemonosignalusesRFmodecompression.Aswithdynamicrange control,

downmixingisultimatelydependentuponeachconsumer’sunique

listening

environment.

Whiletheengineermustoptimizethemultichannelmixforreproductioninanideal

listeningenvironment,itisalsoimportanttopreviewthemixindownmixingconditions

toensurecompatibilitywithdifferentplaybacksystemswhenselectingthedownmixing

metadataparameters.Thesepreviewscanbeachievedinrealtimeusingthe

DP570

MultichannelAudioTool.

D.6 Parameter Definitions

Thissectionexplainsbothprofessionalandconsumermetadataparametersingreater

detail.

Metadataparametersinclude:

•Universalparameters

•ExtendedBitstreamInformation(ExtendedBSI)parameters

ExtendedBSIparametersareactiveonlywhenboththeproducerchoosestousethemand

theconsumer’sdecoderiscapableofreadingthem.Alldecoderscansuccessfullydecodea

metadatastreamwithoutExtendedBSIparameters,andExtendedBSIparameterstranslate

seamlesslytodecodersthatreadonlyuniversalparameters.

D.6.1 Universal Parameters

AlluniversalparametersaresupportedbyDolbyEencodersanddecoders;allexcept

ProgramConfigurationandProgramDescriptionTextaresupportedbyallDolbyDigital

encodersanddecoders.

Program Configuration

ThisparameterdetermineshowtheaudiochannelsaregroupedwithinaDolbyE

bitstream.Uptoeightchannelscanbegroupedtogetherinindividualprograms,where

Note: Universalparametersincludebothprofessionalandconsumermetadata.Table D‐1

onpage 85distinguishesbetweenprofessionalandconsumerparameters.