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.

2Dolby Multistream Decoder Technical Paper

Technical Paper

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

3Dolby Multistream Decoder Technical Paper

Technical Paper

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

4Dolby Multistream Decoder Technical Paper

Technical Paper

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.

5Dolby Multistream Decoder Technical Paper

Technical Paper

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).

6Dolby Multistream Decoder Technical Paper

Technical Paper

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)

7Dolby Multistream Decoder Technical Paper

Technical Paper

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

8Dolby Multistream Decoder Technical Paper

Technical Paper

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.

9Dolby Multistream Decoder Technical Paper

Technical Paper

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.

10Dolby Multistream Decoder Technical Paper

Technical Paper

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

11Dolby Multistream Decoder Technical Paper

Technical Paper

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

12Dolby Multistream Decoder Technical Paper

Technical Paper

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.