Dolby Laboratories DP570 D.4 Dynamic Range Control Profiles

A Guide to Dolby Metadata Dynamic Range Control Profiles
Dolby® DP570 Multichannel Audio Tool User’s Manual 89
devicesareusuallydownmixing(forexample,whenreceivinga5.1‐channelsignal).
However,intheseproducts,theconsumermayhaveachoicebetweenLinemodeandRF
mode.
RF Mode
InRFmode,high‐andlow‐levelcompressionscalingisnotallowed.WhenRFmodeis
active,thatcompressionprofileisalwaysfullyapplied.
RFmodeisdesignedforproducts(suchasset‐topboxes)thatgenerateadownmixedsignal
forconnectiontotheRF/antennainputofatelevisionset;however,itisalsousefulin
situationswhereheavyDRCisrequired—forexample,whensmallPCspeakersareused
forDVDplayback.InRFmode,theoverallprogramlevelisraised11dB,thisresultsin
dialoguebeingreproducedatalevelof–20dBFSLeq(A),whilethepeaksarelimitedto
preventsignaloverloadintheD/Aconverter.Bylimitingheadroom,severe
overmodulationoftelevisionreceiversisprevented.The11dBgainprovidesanaverage
loudnesslevelthatcompareswellwithexistinganalogtelevisionbroadcasts.
Insomesituationsitmaybenecessarytofurtherconstrainsignalpeaksabovetheaverage
dialoguelevelsothatthereislessthan20dBheadroom.TheselectionofasuitableRFmode
profileachievesthis.
D.4 Dynamic Range Control Profiles
SixpresetDRCprofilesareavailabletocontentproducers:FilmLight,FilmStandard,
MusicLight,MusicStandard,Speech,andNone.Eachisappliedinthepatternshownin
Figure D‐2.
Figure D-2 DRC Profile
Ineachcase,thecenterofthenullbandisassignedtotheregionsurroundingoradjacent
totheDialogueLevelparametersetting,andtheDRCprofileisappliedinrelationtothat
level.Herearethedetailsoftherangeforeachprofile.
•FilmLight
MaxBoost:6dB(below–53dB)
BoostRange:–53to–41dB(2:1ratio)
NullBandWidth:20dB(–41to–21dB)
EarlyCutRange:–26to–11dB(2:1ratio)
CutRange:–11to+4dB(20:1ratio)
Input Level
Low High
Boost
Range
Null
Band
Centeredat
theDialogue
LevelSetting
Cut
Range
Cut
Range
Early
Dialogue Level
Setting
Low High
Unity Gain
Ouput Level