A Guide to Dolby Metadata Parameter Definitions
Dolby® DP570 Multichannel Audio Tool User’s Manual 97
parameterduringdownmixinginLo/RomodewhenExtendedBSIparametersarenot
active.
Surround Downmix Level
WhentheencodedaudiohasoneormoreSurroundchannels,buttheconsumerdoesnot
havesurroundspeakers,thisparameterindicatesthenominaldownmixlevelforthe
Surroundchannel(s)withrespecttotheLeftandRightfrontchannels.DolbyDigital
decodersusethisparameterduringdownmixinginLo/RomodewhenExtendedBSI
parametersarenotactive.
Dolby Surround Mode
ThisparameterindicatestoaDolbyDigitaldecodingproductthatalsocontainsaDolby
ProLogicdecoder(forexamplea5.1channelamplifier),whetherornotthetwochannel
encodedbitstreamcontainsaDolbySurround(Lt/Rt)programthatrequiresProLogic
decoding.DecoderscanusethisflagtoautomaticallyswitchonProLogicdecodingas
required.
Table D-8 Center Downmix Level Settings and Definitions

Center Downmix

Level Setting Definition

0.707(–3dB)default TheCenterchannelisattenuated3dBandsenttothe
LeftandRightchannels.
0.596(–4.5dB) TheCenterchannelisattenuated4.5dBandsentto
theLeftandRightchannels.
0.500(–6dB) TheCenterchannelisattenuated6dBandsenttothe
LeftandRightchannels.
Table D-9 Surround Downmix Level Settings and Definitions

Surround Downmix

Level Setting Definition

0.707(–3dB)default TheLeftandRightSurroundchannelsareeachattenuated3
dBandsenttotheLeftandRightfrontchannels,respectively.
0.5(–6dB) Sameasabove,butthesignalisattenuated6dB.
0(–999dB) TheSurroundchannel(s)arediscarded.
Table D-10 Dolby Surround Mode Settings and Definitions

Dolby Surround

Mode Setting Definition

NotDolbySurround Thebitstreamcontainsinformationthatwasnot
encodedinDolbySurround.
DolbySurround Thebitstreamcontainsinformationthatwas
encodedinDolbySurround.AfterDolbyDigital
decoding,thebitstreamisdecodedusingProLogic.
NotIndicated Thereisnoindicationeitherway.