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.
Settopboxes,usedtoreceiveterrestrial,cable,orsatellitedigitaltelevision,typicallyoffer
ananalogmonosignalmodulatedontheRF/Antennaoutput,alinelevelanalogstereo
signal,andanopticalorcoaxialdigitaloutput.DVDplayersofferananalogstereoanda
digitaloutput,andsomeofferasixchannelanalogoutput(fora5.1channelpresentation).
PortableDVDplayersofferanalogstereo,headphone,anddigitaloutputs.DVDplayersin
computersandgameconsolesofferadigitaloutputaswellasanalogstereo,headphone,
andpossiblysixchannelanalogoutputs.5.1channelamplifiers,decoders,andreceivers
havesixchannelanalogoutputsandpossiblysixspeakerleveloutputs.
Inallofthesecases,aDolbyDigitaldecodercreatestheanalogaudiooutputsignal.
InthecaseofthesettopboxorDVDplayer,theanalogstereooutputisadownmixed
versionoftheDolbyDigitaldatastream.ThedigitaloutputdeliverstheDolbyDigitaldata
Table D-2 Outputs from Different Equipment Types
EquipmentOutputDigital 5.1-Channel Analog Two-ChannelAnalog RF Remodulated
5.1channelamplifier
Thestandardhome
theaterA/Vamp
rr
5.1channeldecoder r r
HighendDVDplayer r r r
DVDplayer r r
PC
Includesgamesconsoles
r(someunits) r
Highendsettopbox
OftenHDTV
rr r r
Settopbox
UsuallySDTV
rrr
IDTV
TVsetwithanintegrated
digitalTVtuner
rr
HighendTV
LargescreenTVwitha
5.1channelspeaker
system
rr