Dolby Laboratories DP570 Center Downmix Level , Surround Downmix Level , Dolby Surround Mode

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

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

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

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.