
A Guide to Dolby Metadata Downmixing
Dolby® DP570 Multichannel Audio Tool User’s Manual 91
Aswithstereomixingwherethemixismonitoredinmonoonoccasiontomaintain
compatibility,multichannelaudiomixingrequirestheengineertoreferencethemixto
fewerspeakerchannelstoensurecompatibilityindownmixingsituations.Inthisway,
DolbyDigital,usingthemetadataparametersthatcontroldownmixing,isan“equal
opportunitytechnology,”inthateveryconsumerwhoreceivestheDolbyDigitaldata
streamcanenjoythebestaudioreproductionpossible,regardlessoftheplaybacksystem.
Itisimportanttoconsidertheoutputsignalsfromeachpieceofequipmentthatcanreceive
aDolbyDigitalprograminthehome.Table D ‐2showstheoutputtypesfromdifferent
equipment.
Set‐topboxes,usedtoreceiveterrestrial,cable,orsatellitedigitaltelevision,typicallyoffer
ananalogmonosignalmodulatedontheRF/Antennaoutput,aline‐levelanalogstereo
signal,andanopticalorcoaxialdigitaloutput.DVDplayersofferananalogstereoanda
digitaloutput,andsomeofferasix‐channelanalogoutput(fora5.1‐channelpresentation).
PortableDVDplayersofferanalogstereo,headphone,anddigitaloutputs.DVDplayersin
computersandgameconsolesofferadigitaloutputaswellasanalogstereo,headphone,
andpossiblysix‐channelanalogoutputs.5.1‐channelamplifiers,decoders,andreceivers
havesix‐channelanalogoutputsandpossiblysixspeaker‐leveloutputs.
Inallofthesecases,aDolbyDigitaldecodercreatestheanalogaudiooutputsignal.
Inthecaseoftheset‐topboxorDVDplayer,theanalogstereooutputisadownmixed
versionoftheDolbyDigitaldatastream.ThedigitaloutputdeliverstheDolbyDigitaldata
Table D-2 Outputs from Different Equipment Types
EquipmentOutputDigital 5.1-Channel Analog Two-ChannelAnalog RF Remodulated5.1‐channelamplifier
Thestandardhome
theaterA/Vamp
rr
5.1‐channeldecoder r r
High‐endDVDplayer r r r
DVDplayer r r
PC
Includesgamesconsoles
r(someunits) r
High‐endset‐topbox
OftenHDTV
rr r r
Set‐topbox
UsuallySDTV
rrr
IDTV
TVsetwithanintegrated
digitalTVtuner
rr
High‐endTV
LargescreenTVwitha
5.1‐channelspeaker
system
rr