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A Guide to Dolby Metadata Dynamic Range Control Profiles

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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

Centered at

the Dialogue

Level Setting

Cut

Range

Cut

Range

Early

Dialogue Level

Setting

Low

High

Unity Gain

Ouput Level

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