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Dolby Laboratories DP570 Stereo System User Manual

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DP570 Multichannel Audio Tool User’s Manual 83

Appendix D

A Guide to Dolby Metadata

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document,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

Finally,wedefineeachoftheadjustableparameters,andprovidesamplecombinations:

• Individualparameters

• Metadatacombinations

D.1 Metadata Overview

Dolby

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DigitalandDolbyEarebothdata‐ratereductiontechnologiesthatusemetadata.

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.Innormaloperation,theencodedaudioandmetadataarecarriedtogetheras

a

datastreamontworegulardigitalaudiochannels(AES3,AES/EBU,orS/PDIF).Metadata

canalsobecarriedasaserialdatastreambetweenDolbyEand/orDolbyDigital

equipment.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athomethroughamediumsuchasDTVorDVD.Itconsists

ofasingleencodedprogramofuptosixchannelsofaudiodescribedbyonemetadata

stream.Theconsumer’sDolbyDigitaldecoderreproducestheprogramaudio

accordingto

themetadataparameterssetbytheprogramcreator,andaccordingtosettingsforspeaker

configuration,bassmanagement,anddynamicrangethatarechosenbytheconsumerto

matchhisspecifichometheaterequipmentandenvironmentalconditions.

DolbyEisadistributionbitstreamcapableofcarryinguptoeight

channelsofencodedaudio

andmetadata.Thenumberofprogramsrangesfromonesingleprogram(ProgramConfig:

5.1)toeightindividualprogramsonasingleDolbyEstream(ProgramConfig:8×1).Each

programisdiscrete,withitsownmetadataintheDolbyEstream.Somemetadata

parametersina

DolbyEstreamautoma ticallyconfigureaDolbyDigitalencoderatthe

pointoftransmission,whileothersaffectonlytheconsumer’sDolbyDigitaldecoder

operation.

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