Dolby Laboratories DP570 4.7 Measuring and Setting the Dialogue Level

28 Dolby® DP570 Multichannel Audio Tool User’s Manual
Using the DP570 Features
4.7 Measuring and Setting the Dialogue Level
Thedialoguelevelparameter,alsoknownasdialoguenormalizationordialnorm,isavital
elementinaudiocontentcreation.Theproperdialoguelevelvalueensuresthatthe
consumerhearsdifferentprogramsatthesamelevel.SeeSectionD.2foradetailed
explanationofthedialoguelevelparameter.Thedialoguelevelforeachprogrammustbe
carefullymeasuredandthenappropriatelyset.Thisiseasyusingthecontrolinthe
DialogueLevelSetareaoftheDolbyRemote570,showninFigure 4‐4.
Figure4‐5
Figure 4-4 Measurement Control Options
4.7.1 Identifying Normal or Average Level Program Segments
Tosetthedialoguelevelparameter,thefirstandmostimportantstepisselectingaudioclip
samplesthatrepresenttheaverageloudnessleveloftheprogramcontent.Rememberthat
thedialoguelevelparameterestablishesthelevelfornormaldialogueintheprogram;
quieterandlouderscenestendtoshowhigherorlowermeasurementsthanthecorrect
value.Usingmorethanoneclipisworthwhileparticularlyinprogramsthatfeature
characterswithdifferentvocalqualities.Inprogramswithoutdialogue,suchasamusic
concert,sectionsofaveragelevelneedtobeidentified.
Withrepresentativeaudioclipsidentified,youcanusetheDP570tosetthedialoguelevel
parameter.Youcanuseeitherthesoftwareinterfaceorthefront‐panelbuttons;forthis
operationwedescribeusingthesoftwareinterfacefirst.
4.7.2 Measuring the Average Loudness of Identified Clips
ThemeasurementfeaturecompliesfullywithITU‐RRec.BS.1770AlgorithmstoMeasure
AudioProgrammeLoudnessandTrue‐PeakAudioLevel.Measurementincludestheadditionof
twodistinctmeasurementmodesrelatingtothemeasurementperioditself:infiniteand
short‐term.Thissectiondescribesthebehaviorofbothmodes.
IMPORTANT NOTE REGARDING MEASUREMENT ACCURACY:
Measurementsaremostaccuratewhentheycoversignalswithsimilarspectra,suchas
dialogue;themoresimilarthespectra,themoreaccuratethemeasurement.Thisiswhywe
recommendtheuseofITU‐RRec.BS.1770measurementstoprovisionthedialoguelevel
Note: Thesechangesharmonizeboththecoremeasurementalgorithmandthe
measurementmodesbetweentheDP570,theLM100BroadcastLoudnessMeter,
andtheDP600ProgramOptimizer.