- Dolby Multichannel Audio Tool User's Manual

28 Dolby
®
DP570 Multichannel Audio Tool User’s Manual
Using the DP570 Features
4.7 Measuring and Setting the Dialogue Level
Thedialoguelevelparameter,alsoknownasdialoguenormalizationordialnorm,isavital
elementinaudiocontentcreation.Theproperdialoguelevelvalueensuresthatthe
consumerhearsdifferentprogramsatthesamelevel.SeeSection D.2foradetailed
explanationofthedialoguelevelparameter.Thedialoguelevelforeachprogrammustbe
carefullymeasuredandthenappropriatelyset.This
iseasyusingthecontrolinthe
DialogueLevelSetareaoftheDolbyRemote5 70,showninFigure 44.
Figure45
Figure 4-4 Measurement Control Options
4.7.1 Identifying Normal or Average Level Program Segments
Tosetthedialoguelevelparameter,thefirstandmostimportantstepisselectingaudioclip
samplesthatrepresenttheaverageloudnessleveloftheprogramcontent.Rememberthat
thedialoguelevelparameterestablishesthelevelfornormaldialogueintheprogram;
quieterandlouderscenestendtoshowhigheror
lowermeasurementsthanthecorrect
value.Usingmorethanoneclipisworthwhileparticularlyinprogramsthatfeature
characterswithdifferentvocalqualities.Inprogram swithoutdialogue,suchasamusic
concert,sectionsofaveragelevelneedtobeidentified.
Withrepresentativeaudioclipsidentified,youcanusetheDP570to
setthedialoguelevel
parameter.Youcanuseeitherthesoftwareinterfaceorthefrontpanelbuttons;forthis
operationwedescribeusingthesoftwareinterfacefirst.
4.7.2 Measuring the Average Loudness of Identified Clips
ThemeasurementfeaturecompliesfullywithITURRec.BS.1770AlgorithmstoMeasure
AudioProgrammeLoudnessandTruePeakAudioLevel .Measurementincl udestheadditionof
twodistinctmeasurementmodesrelatingtothemeasurementperioditself:infiniteand
shortterm.Thissectiondescribesthebehaviorofbothmodes.
IMPORTANT NOTE REGARDING MEASUREMENT ACCURACY:
Measurementsaremostaccuratewhentheycoversignalswithsimilarspectra,suchas
dialogue;themoresimilarthespectra,themoreaccuratethemeasurement.Thisiswhywe
recommendtheuseofITURRec.BS.1770measurementstoprovisionthedialoguelevel
Note: Thesechangesharmonizeboththecoremeasurementalgorithmandthe
measurementmodesbetweentheDP570,theLM100BroadcastLoudnessMeter,
andtheDP600ProgramOptimizer.