- Dolby Multichannel Audio Tool User's Manual

96 Dolby
®
DP570 Multichannel Audio Tool User’s Manual
A Guide to Dolby Metadata
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
parameterduringdownmixinginLo/Ro
modewhenExtendedBSIparametersarenot
active.
Surround Downmix Level
Whentheencodedaudiohasoneormoresurroundchannels,buttheconsumerdoesnot
havesurroundspeakers,thisparameterindicatesthenominaldownmixlevelforthe
surroundchannel(s)withrespecttotheLeftandRightfrontchannels.DolbyDigital
decodersusethisparameterduringdownmixinginLo/RomodewhenExtended
BSI
parametersarenotactive.
Dolby Surround Mode
ThisparameterindicatestoaDolbyDigitaldecodingproductthatalsocontainsaDolby
ProLogicdecoder(forexample,a5.1‐channelamplifier)whetherornotthetwo‐channel
encodedbitstreamcontainsaDolbySurround(Lt/Rt)programthatrequiresProLogic
decoding.Decoderscanusethisflagtoautomaticallyswitchon
ProLogicdecodingas
required.
Table D-8 Center Downmix Level Settings and Definitions
Center Downmix Level
Setting
Definition
0.707(–3dB)default TheCenterchannelisattenuated3dBandsenttothe
LeftandRightchannels.
0.596(–4.5dB) TheCenterchannelisattenuated4.5dBandsenttothe
LeftandRightchannels.
0.500(–6dB) TheCenterchannelisattenuated6dBandsenttothe
LeftandRight
channels.
Table D-9 Surround Downmix Level Settings and Definitions
Surround Downmix
Level Setting
Definition
0.707(–3dB)default TheLeftSurroundandRightSurroundchannelsareeach
attenuated3dBandsenttotheLeftandRightfrontchannels,
respectively.
0.5(–6dB) Sameasabove,butthesignalisattenuated6dB.
0(–999dB) Thesurroundchannel(s)arediscarded.
Table D-10 Dolby Surround Mode Settings and Definitions
Dolby Surround Mode
Setting
Definition
NotDolbySurround Thebitstreamcontainsinformationthatwasnot
encodedinDolbySurround.
DolbySurround Thebitstreamcontainsinformationthatwasencoded
inDolbySurround.AfterDolbyDigitaldecoding,the
bitstreamisdecodedusingProLogic.
NotIndicated Thereisnoindicationeitherway.