86 Dolby® DP570 Multichannel Audio Tool User’s Manual
A Guide to Dolby Metadata Dialogue Level

Special Parameters

ThereareprofessionalparametersintheDolbyEbitstreamthatarenotunderdirectuser
control,suchasTimecodeandPitchShift.

Timecode

DolbyEbitstreamscarrytimecodeinformationinhours:minutes:seconds:framesformat.

Pitch Shift

ThePitchShiftparametercanbegeneratedautomaticallybyaDolbyEdecodertocontrol
theDolbyModel585TimeScalingProcessor.IftheinputtotheDolbyEdecoderisnotat
normalplayspeed(aswithvarispeedorprogramplay),thenthePitchShiftCode
parameterindicatestheamountofaudiopitchshiftingrequiredtorestoretheoriginal
programpitch.
D.2 Dialogue Level
DialogueLevel(alsoknownasdialoguenormalizationordialnorm)isperhapsthesinglemost
importantmetadataparameter.TheDialogueLevelsettingrepresentsthelongterm
Aweightedaveragelevelofdialoguewithinapresentation,Leq(A).Thislevelcanbe
quantifiedwiththeDolbyModelLM100BroadcastLoudnessMeter.
Whenreceivedattheconsumer’sDolbyDigitaldecoder,thisparametersettingdetermines
alevelshiftinthedecoderthatsets,ornormalizes,theaverageaudiooutputofthedecoder
toapresetlevel.Thisaidsinmatchingaudiovolumebetweenprogramsources.
Inbroadcasttransmission,thepropersettingofDialogueLevelensuresthattheconsumer
receivesastandardlisteninglevel,soswitchingchannelsorwatchingatelevisionprogram
throughthecommercialbreaksdoesn’trequireadjustingthevolume.Usingthesame
standardforallcontent,whetherconveyedbybroadcasttelevision,DVD,orothermedia,
enablestheconsumertoswitchbetweensourcesandprogramswhilemaintaininga
comfortableandconsistentlisteninglevel.
ThepropersettingoftheDialogueLevelparameteralsoenablestheDynamicRange
Controlprofileschosenbythecontentproducertoworkasintendedinlessthanoptimal
LowpassFilter x
LFELowpassFilter x
Surround3dBAttenuation x
SurroundPhaseShift x
a.ExtendedBitstreamInformationparametersareshowninitalics.
Table D-1 Profession and Consumer Metadata Types <~Figure>(continued)

Metadata Parameter Professional Consumer