Dolby Laboratories DP570 A Guide to Dolby Metadata

Dolby® 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

Dolby®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automaticallyconfigureaDolbyDigitalencoderatthe

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

operation.