Dolby Laboratories DP570 Line Mode Compression Profile and RF Mode Compression Profile , RF Overmodulation Protection , Center Downmix Level

96 Dolby® DP570 Multichannel Audio Tool User’s Manual

A Guide to Dolby Metadata Parameter Definitions

Line Mode Compression Profile and RF Mode Compression Profile

Fordetailsoftheavailableprofiles,seeDynamicRangeControlProfilesonpage89.

RF Overmodulation Protection

ThisparameterisdesignedtoprotectagainstovermodulationwhenadecodedDolby

DigitalbitstreamisRFmodulated.Whenenabled,theDolbyDigitalencoderincludes

pre‐emphasisinitscalculationsforRFModecompression.Theparameterhasnoeffect

whendecodingusingLinemodecompression.Exceptinrarecases,thisparametershould

bedisabled.

Center Downmix Level

Whentheencodedaudiohasthreefrontchannels(L,C,R),buttheconsumerhasonlytwo

frontspeakers(leftandright),thisparameterindicatesthenominaldownmixlevelforthe

CenterchannelwithrespecttotheLeftandRightchannels.DolbyDigitaldecodersusethis

Assc.Commentary(C) Thisistypicallyasingle‐channelprogramintendedtoconvey

additionalcommentarythatcanbeoptionallydecodedalongwith

themainaudioservice.Thisservicediffersfromadialogueservice

becauseitcontainsanoptional,ratherthanarequired,dialogue

channel.TheCservicemayalsobeacompletemixofallprogram

channels,comprisinguptosixchannels.

Assc.Emergency(E) Thisisasingle‐channelservicethatisgivenpriorityin

reproduction.WhentheEserviceappearsinthebitstream,itis

givenpriorityinthedecoderandthemainserviceismuted.

Assc.Voice Over(VO) Thisisasingle‐channelserviceintendedtobedecodedandmixed

totheCenterchannel(requiresspecialdecoders).

MainSvKaraoke(K) Thebitstreamisaspecialserviceforkaraokeplayback.Inthiscase,

theLeftandRightchannelscontainmusic,theCenterchannelhasa

guidemelody,andtheLeftandRightSurroundchannelscarry

optionalbackingvocals.

Table D-7 RF Overmodulation Protection Setting

Enabled

Disabled

Table D-6 itstream Mode Options