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1Dolby Multistream Decoder Technical Paper
Technical Paper
Audio for Next-Generation Broadcast Services: The Dolby MS10 Multistream Decoder Solution
Summary
• Twomultichannelaudioformats—Dolby®DigitalPlusandDolbyPulse—areattractivefornext-generationbroadcastsfordifferentreasons,anditislikelythatbothwillbeusedfornewEuropeanservices.
• KeynewEuropeanHDTVreceiverspecificationsincludebothDolbyDigitalPlusandDolbyPulse.
• Dolbyisdevelopinganewmultiformataudiodecoderimplementationthatwilleasetheinclusionofdualdecodersinnewreceivers.
Broadcaster and Operator Requirements
Overthelast18months,variousEuropeanindustrygroupssuchasDVB,EBU,EICTA,andanumberofnationalHDTVspecificationforumshaveconsideredtheselectionofaudiocodingsystemsfornext-generationbroadcastapplications,includingHDTVbroadcasts,usingMPEG-4video.Ingeneral,theseconsiderationshavehighlightedtwostandardizedaudiocodingsystemsasparticularlysuitedtonext-generationtransmissions:DolbyDigitalPlus(alsoknownasE-AC-3)andDolbyPulse(Dolby’simplementationofaacPlusorHEAAC).TheEBUProjectGroupD/MAE,forexample,concludedthatthetwocodingformatsarethebestcandidatesforbroadcastingHDTVaudioservicesviasatellite,cable,terrestrial,andIPTVnetworks.
Duetothediversemarketrequirementsofdifferentbroadcasters/operatorsandthedifferingfeaturesetsofthesetechnologies,ithasnotgenerallybeenpossibleforthesegroupstorecommendasingleaudiosystemthatsuitsallapplications.Forexample,DolbyDigitalPluscurrentlyofferscomprehensivesupportfor5.1-channelsoundaswellasadvancedmetadatasupport.DolbyPulsewillalsoofferthissupportinthenearfuture,alongwithitsalreadyformidablecodingefficiency,whichtodayenablesqualitystereoservicestobetransmittedatextremelylowdatarates.
Inaddition,over200EuropeanTVservicesalreadybroadcastwithconventionalDolbyDigitalaudio,sonext-generationreceiverstypicallyneedtobecompatiblewiththisformat.
While Dolby Laboratories intends to distribute a commercial release of the Dolby Multistream Decoder, Dolby Laboratories reserves the right, at any time, not to release a commercial release of Dolby Multistream Decoder or, if it does so, to alter prices, features, specifications, capabilities, functions, licensing terms, release dates, general availability, or other characteristics of the commercial release.
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European HDTV Receiver Specifications
AsDVBdoesnotspecifywhichaudiocodershouldbeusedfornext-generationbroadcasts,variousbroadcaster/manufacturergroupshaverecentlyworkedcollaborativelytogainconsensusontheformatsdesiredbybroadcasters,whichwillthenbeincludedinEuropeanreceivers.ThekeyoutcomesformultichannelformatrequirementssofararedescribedinTable1.
High Definition Terrestrial Specification
Dolby Digital Plus HE AAC with Transcoder
DTG HD Digital Terrestrial (UK) √ √ (transcoder not required)
EBU (Tech 3333) √ √
EICTA (known as Digital Europe) √ √
France HD DTT √ √
Ireland HD DTT √ √
Italy HD DTT √ √
NorDig HD DTT (Denmark, Finland, Iceland, Norway, and Sweden) √ √
Poland HD DTT √RiksTV (Norwegian Terrestrial Broadcast) √
Slovenia HD DTT √ √Spain HD DTT √ √
Note: DTT=Digital Terrestrial Television. Visit www.dolby.com/EuroHDTVSpecs for the latest updates.
Table 1 Multichannel Format Requirements in European HDTV Specifications, June 2009
Notes
1. The EBU Project Group D/MAE states that Dolby Digital Plus and Dolby Pulse are the best candidates for broadcasting HDTV. It states that both Dolby Digital Plus and HE AAC have advantages, and a single preference cannot currently be identified. Dolby Digital (Plus) offers consistently great performance at 448 kbps and above; HE AAC offers remarkable performance where data rate is limited.
2. The EICTA HDTV receiver specification requires Dolby Digital Plus or Dolby Pulse with transcoder output. A single universal audio solution has not been identified, so effectively both will be included unless manufacturers can be sure that a single format will be transmitted in all regions where the product is sold.
3. Whereas an HE AAC multichannel decoder (with downmix capacity) is required from the start of the service in October 2008, an HE AAC transcoder will be required after December 31, 2009.
4. NorDig requires dual decoders unless the operator can guarantee that a single audio format will be used within the entire market for the product.
A New Multiformat Audio Decoding Solution
InNovember2007,DolbyLaboratoriesacquiredCodingTechnologies,theleadingcontributortotheHEAACstandard.DolbyintendstobringtomarketanewlicensableaudiodecoderimplementationthatofferssupportforbothDolbyDigital
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Plus(includingDolbyDigital)andDolbyPulsedecodinginasinglepackage.Thisimplementationwillreducethecomplexityandcostofintegratingallaudiotechnologiesinnewreceivers.Itwillalsosimplifyproductdevelopmentandtesting
whilemeetingcurrentrequirementsfornext-generationHDTVservices.
Figure 1 Block Diagram of the Multiformat Dolby MS10 Multistream Decoder for Broadcast Devices,
TVs, and Set‑Top Boxes
TheDolbyMS10MultistreamDecoderwillofferthefollowingkeybenefits:
• Auniversalsolutionthatmaintainsflexibilityforbroadcasterstochoosetheformatthatbestsuitstheirrequirements:DolbyDigital,DolbyDigitalPlus,orDolbyPulse.
• Easeofimplementationbecausedeliverables,technicalsupport,andtestingareavailablefromasinglesource:Dolby.
• ReducedlicensingcostscomparedwiththeexistingDolbyDigitalPlus,DolbyPulse,andtranscoderoption.
• FullcompatibilitywithDolbymetadataandconsumers’existingDVDhomecinemasystemswithalltransmissionformats.
• Fullmultichannelsupport(transcoder)forDolbyPulseinadditiontoDolbyDigitalandDolbyDigitalPlusdecodingandconversion.OneDolbyDigitaloutputforallinputformats.
• Supportforaudiodescriptionservicesdelivered“receiver-mix”styleusingtwosimultaneousinstancesofDolbyPulse,DolbyDigital,orDolbyDigitalPlusdecoders,respectively—allforthepriceofasingledecoderinstance.
• SupportformultiprogramDolbyDigitalPlusstreams(mainandassociatedaudiodeliveredinthesameaudiostream).
Theintegrateddecoder/transcoderandconvertercombinestheabilitytodecodeDolbyDigital,DolbyDigitalPlus,andDolbyPulsewithinoneproduct.AlloftheseinputsignalscomingintothedecodersforthemainaudioarepassedthroughunalteredforoutputoverHDMI™andS/PDIFinterfaces(DolbyDigitalPlusisconvertedtoDolbyDigital;DolbyPulsewillbepassedonceinterfacedefinitionsarefinal).*Thesignalscomingintothedecodersforassociatedaudioarenotpassedthroughthesystembutaredecodedandsenttothemixingengineinsteadtosupportthereceiver-mixaudiodescription.
Atthesametime,atwo-channeldownmixisalwayscreatedfromanyoftheinputformatsinordertosupportdecodedoutput(forexample,foranalogoutputs)ofa
Dolby Digitalencode
Dolby Pulsedecode
Dolby DigitalorDolby Digital PlusorDolby Pulse
Stereo outputs
Audio and metadata
Pass-through on HDMI
Mixing metadata
Dolby Digital bitstream for existing home cinemas
Dolby Digital /Dolby Digital Plusdecode/convert
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broadcastdevice.FormaximumcompatibilityandforconnectivityoverS/PDIFandHDMIinterfaces,amultichanneldecoderforDolbyPulseisintegratedtofeedanembeddedDolbyDigitalencoderwithamultichannelsignal(upto5.1channels),whichthenoutputsastandardDolbyDigitalbitstream(upto5.1channels)atafixedbitrateof640kbps.
DolbyDigitalandDolbyDigitalPlusinputsarehandledbytheintegratedDolbyDigitalPlusdecoder/converter.Thisprovidesatwo-channeldownmixfordecodedoutputswhileconvertingDolbyDigitalPlusstreamstoDolbyDigitalinordertoprovidemaximumcompatibilityontheS/PDIFoutput.
TheDolbyMS10MultistreamDecodersupportssimultaneousdecodingofmainandassociatedaudioforDolbyPulseandDolbyDigital/DolbyDigitalPlus,respectively,tosupportbasictwo-channelmixing(Dual-Decodemode)inordertomeetEuropeanbroadcastspecificationsfornext-generationaudio.Audiowillbemixedinanexternalmixingmoduleoutsideofthedecoder.However,thesystemwillprovidethemixingmetadatapotentiallycarriedwithinDolbyDigitalPlusasaserialbitstreamononeofitsoutputs.Thismixingmetadatashallbeusedtocontrolthemixintheexternal/system-levelmixingmodule.Theimplementationofdualdecoding(Dual-Decodemode)isoptionalbutstronglyrecommended.
* Transmission of Dolby Pulse streams via HDMI or S/PDIF connections will be enabled in the future as the specifications necessary to transmit the technology across these interfaces are completed.
Comparing AAC Varieties and Dolby Pulse
DolbyPulseisanenhancedandoptimizedimplementationoftheMPEG-4AACfamilyofaudiocodecs.ItisdesignedbyDolbytobringadditionalfunctionality,flexibility,andreliabilitytotheformatwhileremainingfullybackward-andforward-compatiblewithMPEG-4AAC,MPEG-4HEAAC,andMPEG-4HEAACv.2asdefinedinISO/IEC14496-3:2005.
AdvancedAudioCoding(AAC)isaperceptualcodingmethodusedtocompressdigitalaudioforefficientstorageandtransmission.Uponplayback,theexpandedfilescanprovidesoundqualitynearlyindistinguishablefromtheoriginalsources.Inprinciple,AACissimilartoMP3,butitoffersanumberofadvantages:
• Moreefficientcompression• Highersamplingfrequencies• Betterfrequencyresponse• Morechannels
HEAACaddsspectralbandreplication(SBR)toimproveefficiencyandlowerbitrates.InadditiontoSBR,HEAACv.2usesParametricStereo(PS)tofurtherimproveefficiencyandlowerbitratesbytransmittingamonochannelwithparametricinformationtoextractstereofromit.BothSBRandPSarebackward-andforward-compatible.Asaresult,HEAACoffers5.1audioat160kbps,nearlyCD-qualitystereoat32kbps,andexcellent-qualitystereoat24kbps.
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DolbyPulseisbasedontheAACfamilyofcodecs.ADolbyPulsedecodercontainsanHEAACv.2decoderwhichcandecodeAAC,HEAAC,andHEAACv.2bitstreams,thusrealizingthefullpotentialofthesetechnologies.
ThemaindifferencebetweenDolbyPulseandstandardMPEG-4HEAACisthesupportforaudiometadata.ThespecificationforMPEG-4HEAACdescribesanumberofoptionalmetadataparameterstocontrolthereproductionoftheaudiosignalinaconsumerdevicesuchasaset-topboxoratelevisionset.
DolbyPulseintegratesallmetadataparametersrequiredtoallowthesystemtofunctionasabroadcastaudiosystemsuchasDolbyDigitalandDolbyDigitalPlus.Italsoofferssignificantimprovementsinthefollowingareas:
• Decoder stability:ComparedtogenericHEAACimplementations,DolbyPulseoffershighlyoptimizedswitchingtimesbetweenchannelconfigurationsandimprovedreliabilitywhenusedinasystemwithDolbyPulseencoders.
• Error concealment:SophisticatederrorconcealmentmechanismshavebeenaddedtoDolbyPulsetoensurereliablebroadcastaudioperformance.
• Decoder requirements in terms of memory and computational complexity:DolbyPulsedecodingwithintheDolbyMultistreamDecoderplatformisintegratedintoacombinedcodebasethatisoptimizedforH.264system-on-chiparchitectures.
• Encoder audio quality:DolbyPulseofferssuperioraudioqualitycomparedtootherparametricaudiocodecs.
SincetheinclusionofaudiometadatainMPEG-4AAC–basedbitstreamsisoptional,theDolbyMS10MultistreamDecoderfeaturesmechanismswithinitstranscoderthatoptimizeaudioqualityincaseswhereanincomingstandardMPEG-4HEAACbitstreamthatcontainsnometadataisbeingdecoded.BestpossibleperformanceoftheentirebroadcastsystemcanonlybeachievedwhentheDolbyMultistreamDecoderprocessesaDolbyPulsestreamgeneratedbyanappropriateDolbyPulseencoder.
TheDolbyMultistreamDecoderhandlesvarioustypesofAACcontenttoPCM,andsimultaneouslytranscodesthiscontenttoDolbyDigitalformultichannelbitstreamoutput.AACformatssupportedinclude:
• DolbyPulse• aacPlus• MPEG-2/4AAC• MPEG-4HEAAC• MPEG-4HEAACv.2
TheDolbyMS10MultistreamDecoderplatformisdesignedtoinitiallysupportDVBdevicesonly(LATM/LOASformatting).However,thesourcecodedeliverablesalreadycontainsupportfortheuseoftheDolbyMultistreamDecoderinbroadcastdevicesdesignedforARIB(ISDB-T)systems.FullsupportofARIBwillrequiremodificationstotheimplementationdevelopmentkits(IDKs)andsystemdevelopmentkits(SDKs).
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Figure 2 Dolby Pulse’s Feature Set Exceeds That of Any Existing AAC Solution While Remaining Fully
Backward‑Compatible and in Line with MPEG‑4 Specifications
ThesupportfortheextendedfeaturesofDolbyPulseisimplementedinadedicatedcodebasethatispartoftheDolbyMS10MultistreamDecoder.ThisextendedcodebaserefinesthecapabilitiesandreliabilityofexistingHEAACoraacPlusdecodersandisthereforeanessentialanduniqueingredientoftheDolbyMultistreamDecoderimplementation.However,theDolbyMultistreamDecoderprovidesfullbackward-andforward-compatibilitytoallAACimplementationsandbitstreams;DolbyMultistreamDecoderswillalwaysbeabletodecodeanyformofAACaudio,whileDolbyPulsestreamscanbedecodedonanyHEAACdecoderplatform(althoughwithreducedfunctionalityandperformance).
Broadcast Mix Versus Receiver Mix
Audiodescriptionhaslongbeenprovidedbybroadcastservices.ThePALsystem,forexample,makesitpossibleforthesecondFMsoundsubcarrier,otherwiseusedfortheRightchannelinstereotransmissions,tocarryanalternativeversionofthemainsoundtrackcarriedonthefirstFMsubcarrier.Whilethis“broadcast-mix”approachlimitsthetransmissiontomonomainandassociatedaudiosoundtracks,itisanefficientwaytoprovideabasicserviceforthevisuallyimpaired.Figure3showsthesymbolusedbyEuropeanbroadcasterstomarktransmissionsofferingaudiodescription.
Figure 3 Symbol Used by European Broadcasters for Transmissions Offering Audio Description
Thisbroadcast-mixapproach,wherebythemainandcommentarytracksaremixedinpostproductionpriortotransmission,wascarriedoverintodigitaltelevision(DTV)systemsbecauseearlyreceiversofferedonlybasicfunctionalityandthesourcesfordigitaltransmissionswereoftenstillstoredonanalogmedia.ThisapproachisalsosimilartothattakenbytheNTSCsystemwhereasecondaryaudioprogram(SAP)carriesapremixedversionofmainandaudiodescriptiontracksasamonosignal.However,duetotheaffiliatebroadcaststructureintheUS,technical
Dolby Pulse
aacPlus
HE AAC (including AAC)
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impedimentscaninterferewithpassingthroughaSAPsignaloncableandsatellitesystems,makingtheservicelessaccessibletoviewers.
ManyEuropeanpublicbroadcastersofferingalargeportionoftheirprogrammingwithaudiodescriptionservicesarefacingthechallengeofcontinuingtodistributetheiraudiodescriptionservice“analogstyle”—thatis,leavingmainaudioontheLeftchannelandaudiodescriptionontheRightchannelofwhatisbasicallythemainbroadcastaudiotrackcarriedasastereosignalbutsignaledasdualmono.ThisrequiresbroadcastreceiverstopassonlytheLeftchannelorRightchanneltotheiraudiooutputs.However,sincethisisnotarequirementwithinDVB,whichmandatesthatdifferentaudioservicesbetransmittedandsignaledusingdifferentaudioPIDs,receivingandrecordingtheseservicesbecomesamajorchallenge.
Todate,transmittingaudiodescriptionservicesintheformofabroadcastmixisstandardpracticeinmanypartsoftheworld.Effortstoofferamoreefficientwaytoprovideservicesforthevisuallyimpairedintheformofareceiver-mixapproachhaveculminatedinthecreationofaspecificationthatisnowpartofDVB.
AnnexEofETSITS101154describesabasicapproachtotransmittinganisolatedmonosignalcontainingthedescriptiontrackalongsidethemainsoundtrackasaseparatebitstream.Asuitablebroadcastreceivercanthenperformthemixingofthemainsoundtrackwiththecommentarytrackinthedeviceitself,hencetheterm“receivermix.”
Figure4showsthereceiver-mixarchitecturedesignedtosupportmixingforaudiocodecssupportedbytheDolbyMS10MultistreamDecoderaswellasfromothersourcessuchasMPEG-1LayerII.
Figure 4 Mixing Support for Audio Description as Part of the Dolby MS10 Multistream Decoder
Transcode
Set-top box/TV
Dolby MS10
Main
Associated
Two-channelPCM
Two-channelPCM
Mixing metadata
Dolby Digital bitstream(unmixed)
to S/PDIFand/or HDMI
to analog and/orS/PDIF, HDMI
to analog and/orS/PDIF, HDMI(mixed)
Decode
Decode
Two-channel PCM mixer
for AD
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Mixing Architecture
Themixingofassociatedaudiostreamsdeliveredassubstreamswiththemainbroadcastaudioorasseparatelow-bit-rateaudiostreamsenablesservicessuchasaudiodescriptionsforthevisuallyimpairedordirectorcommentaries,whileatthesametimemaintainingthehighestpossiblebandwidthefficiency.
Thisreceiver-mixapproachnegatestheneedforbroadcasterstotransmitseveralfinalmixestosupportmultipleaudiencepreferences.Itisnecessaryonlytoaddlow-bandwidthsubstreamscontainingtheadditionalinformationalongwithmixingmetadatathatdetermineshowtheassociatedaudiostreamiscombinedwiththemainbroadcastaudiotrackinthereceivingdevice.ThereisstrongdemandforthisfeaturefrompublicbroadcastersinEuropeforfutureapplications,anditcanaddanotherdifferentiatingfeaturetobroadcastdevicesthatwillhelptodrivethesuccessofnext-generationdigitaltelevisionservicesaroundtheworld.
Audio Service Codec Substream Usage Channel Configuration
Main Dolby Digital (AC‑3) N/A Up to 5.1 channels
Dolby Digital Plus (E‑AC‑3)
Independent substream 0
Up to 7.1 channels
Dolby Pulse (aacPlus) N/A Up to 7.1 channels
Associated: Delivered in same bitstream as main audio service (as described in ETSI TS 102 366)
E‑AC‑3 (main audio must be AC‑3 or Enhanced AC‑3)
Independent substream 1
Independent substream 2
Independent substream 3
Up to 7.1 channels
Associated: Delivered in separate MPEG PES
E‑AC‑3 (main audio must be AC‑3 or E‑AC‑3)
Independent substream 0
Up to 7.1 channels
aacPlus (main audio must be aacPlus)
N/A
Table 2 Input Formats for Main and Associated Audio Supported by the Dolby MS10 Multistream Decoder
Thisdesignsupportsmixingonemainaudioservicewithoneassociatedaudioservice.TheassociatedservicecanbedeliveredinthesameE-AC-3bitstreamasthemainservicethroughtheuseofanadditionalindependentsubstream,orasanE-AC-3bitstreamcarriedinaseparateMPEGPES.InthecaseofDolbyPulse,theassociatedaudioserviceisdeliveredasaDolbyPulsebitstreamcarriedinaseparateMPEGPES.
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R
L
R
C
L
Assoc.audio
Mixing metadata
User level adjust
Mainaudio
Figure 5 Mixer: 2/0 Main Audio, 1/0 Associated Audio (Panning Metadata Enabled)
R
L
R
L
R
L
Mainaudio
decode and
down- mix
Multichannel bitstream
Multichannel bitstream
Mixing metadata
User level adjust
Assoc.audio
decode and
down- mix
Figure 6 Mixer: 2/0 Main Audio, 2/0 Associated Audio (Panning Metadata Disabled)
InformationonthetypeofassociatedaudioserviceiscarriedintheDolbyDigitalPlusorDolbyPulsedescriptorthatisfoundintheprogrammaptable(PMT)oftheincomingMPEG-2transportstream.
EachDolbyDigitalPlusorDolbyPulsebitstreamusedforthebroadcastservicehasanidentifyingdescriptorthatthebroadcastreceiverdeviceusestoinformtheuserwhichassociatedaudioservicesareavailable.Whentheuserselectsadesiredservice,thebroadcastreceiverdevicedemultiplexesitfromtheMPEGtransportstreamanddeliversittotheDolbyMS10MultistreamDecoder.Thefollowingexamplesillustratehowthisapproachworksinpractice.
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Example 1
DVB TS
Dolby Digital Plus main
Two-channel PCM main
Dolby Digital Plus associated
Two-channel PCM associated
DemuxDolby MS10MultistreamDecoder
Mixing
Figure 7 Main and Associated Audio Delivered as Dolby Digital Plus in Separate Elementary Streams
TheuserselectsanassociatedaudioservicebeingcarriedinaseparateMPEGPESassociatedwiththemainaudioservicethroughitsDolbyDigitalPlusdescriptor(seeFigure7).ThebroadcastreceiverdemultiplexesbothDolbyDigitalPlusstreamsfromthebroadcasttransportstream,andpassesthemtobothinputsoftheDolbyMultistreamDecoder.Thedecoderreceivesinformationontheuser’sstreamselectionfromthesystemlayerofthebroadcastreceiverdeviceandactivatesbothinputs,thendecodesandmixesthetwostreams.ThemixingmetadataiscarriedintheDolbyDigitalPlusbitstreamscontainingtheassociatedaudiotrack.
Example 2
Figure 8 Main and Associated Audio Delivered as Dolby Digital Plus in One Multiprogram
Elementary Stream
TheuserselectsanassociatedaudioservicethatisbeingcarriedinanadditionalindependentsubstreamwithintheDolbyDigitalPlusmainaudiobitstream(seeFigure8).Thebroadcastreceiverdemultiplexesonlythemainaudiobitstream,whiletheDolbyMS10MultistreamDecoderreceivesinformationontheuser’sassociatedserviceselectionfromthesystemlayerofthebroadcastreceiverdeviceandactivatesitsmainaudioinputonly.Thedecoderthenusesthesubstreamparserinthemainaudiochaintoseparateindependentsubstream0(mainaudio)fromtheindependentsubstreamcarryingtheassociatedaudio.Theassociatedaudioserviceisthenroutedinsidethedecodertotheassociatedaudioinputofthemixer,andbothindependentsubstreamsaredecodedandmixed.ThemixingmetadataiscarriedintheDolbyDigitalPlusbitstreamscontainingtheassociatedaudiosoundtrack.
DVB TS
Dolby Digital Plus main andassociateddelivered as multiprogram stream
Two-channel PCM main
Two-channel PCM associated
Demux MixingDolby MS10 MultistreamDecoder
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Example 3
DVB TS
Dolby Pulse main
Two-channel PCM main
Dolby Pulse associated
Two-channel PCM associated
Demux MixingDolby MS10 MultistreamDecoder
Figure 9 Main and Associated Audio Delivered as Dolby Pulse in Separate Elementary Streams
TheuserselectsanassociatedaudioservicethatisbeingcarriedinaseparateMPEGPESassociatedwiththemainaudioservicethroughitsDolbyPulsedescriptor(seeFigure9).ThebroadcastreceiverdemultiplexesbothDolbyPulsestreamsfromthebroadcasttransportstream,andpassesthesestreamstobothinputsoftheDolbyMS10MultistreamDecoder.Thedecoderreceivesinformationontheuser’sassociatedserviceselectionfromthesystemlayerofthebroadcastreceiverdevice,activatesbothinputs,thendecodesandmixesthetwoDolbyPulsebitstreams.ThemixingmetadataiscarriedinthePESheaderinformationoftheDolbyPulsebitstreamsandhastobepassedtothedecoderfromthesystem-levelparserofthebroadcastreceiverdevice.
The Complete System Architecture
DolbyisalsodevelopingprofessionalmultichannelencodingsolutionsintendedtofurthersimplifytheuseofDolbyPulseforbroadcasts,includingfullsupportforDolbymetadataandcompatibilitywithexistingDolbyEinfrastructure.
Dolby Digital encoder
Dolby Digital Plus encoder
Dolby Pulse encoder
Generic AAC or HE AAC encoder
Dolby Digital bitstreams
Dolby Digital Plus bitstreams
Dolby Pulse bitstreams
AAC, HE AAC bitstreams*
Dolby MS10MultistreamDecoder
Figure 10 Dolby Multistream Decoder Supports the Dolby Family of Broadcast Bitstreams with Maximum Features and
Functionality Within Dolby Digital Plus and Dolby Pulse Systems
* Generic AAC and HE AAC streams are supported but limited to basic functionality as specified in ISO/IEC 14496-3:2005.
Dolby Laboratories, Inc.100 Potrero Avenue, San Francisco, CA 94103‑4813 USA T 415‑558‑0200 F 415‑863‑1373Wootton Bassett, Wiltshire SN4 8QJ England T 44‑1793‑842100 F 44‑1793‑842101
dolby.com
Dolby and the double‑D symbol are registered trademarks of Dolby Laboratories. HDMI is a trademark of HDMILicensing, LLC. © 2009 Dolby Laboratories, Inc. All rights reserved. S09/21627/21883
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Conclusion
Duetodifferingrequirementsamongbroadcasters,Dolbyrecommendsthatnext-generationreceiverspecificationsgenerallyincludebothDolbyDigitalPlusandDolbyPulsedecoding.ThisisinlinewithrecentspecificationspublishedbymanyEuropeanbroadcaster/manufacturergroups,whichdonotidentifyasinglepreferredaudiooption(chart,page2).TheDolbyMS10MultistreamDecoderimplementationwillsignificantlyeasethedesignandmanufacturingofreceiversincludingdualaudiodecoders.
Resources
StandardsdocumentETSITS102366,V1.2.1,“DigitalAudioCompression(AC-3,EnhancedAC-3)Standard,”August2008.
StandardsdocumentETSITS101154,V1.8.1,“DigitalVideoBroadcasting(DVB):SpecificationfortheUseofVideoandAudioCodinginBroadcastingApplicationsBasedontheMPEG-2TransportStream,”January2007.
LouisD.Fielderetal.,“IntroductiontoDolbyDigitalPlus,anEnhancementtotheDolbyDigitalCodingSystem,”117thAESConvention,October2004.
AdvancedTelevisionSystemsCommittee,“DigitalAudioCompressionStandard(AC-3,E-AC-3)RevisionB,DocumentA/52B,”June2005.
StandardsdocumentISO/IEC14496-3:2005,“InformationTechnology—CodingofAudio-VisualObjects—Part3:Audio,”January2005.