ITU-T G.729.1 (05 2006) (英) G.729 based Embedded V

InternationalTelecommunicationUnionITU-TG.729.1TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITU(05/2006)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalterminalequipments–CodingofanaloguesignalsbymethodsotherthanPCMG.729-basedembeddedvariablebit-ratecoder:An8-32kbit/sscalablewidebandcoderbitstreaminteroperablewithG.729ITU-TRecommendationG.729.1ITU-TG-SERIESRECOMMENDATIONSTRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSINTERNATIONALTELEPHONECONNECTIONSANDCIRCUITSG.100–G.199GENERALCHARACTERISTICSCOMMONTOALLANALOGUECARRIER-TRANSMISSIONSYSTEMSG.200–G.299INDIVIDUALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONMETALLICLINESG.300–G.399GENERALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONRADIO-RELAYORSATELLITELINKSANDINTERCONNECTIONWITHMETALLICLINESG.400–G.449COORDINATIONOFRADIOTELEPHONYANDLINETELEPHONYG.450–G.499TRANSMISSIONMEDIACHARACTERISTICSG.600–G.699DIGITALTERMINALEQUIPMENTSG.700–G.799GeneralG.700–G.709CodingofanaloguesignalsbypulsecodemodulationG.710–G.719CodingofanaloguesignalsbymethodsotherthanPCMG.720–G.729PrincipalcharacteristicsofprimarymultiplexequipmentG.730–G.739PrincipalcharacteristicsofsecondordermultiplexequipmentG.740–G.749PrincipalcharacteristicsofhigherordermultiplexequipmentG.750–G.759PrincipalcharacteristicsoftranscoderanddigitalmultiplicationequipmentG.760–G.769Operations,administrationandmaintenancefeaturesoftransmissionequipmentG.770–G.779PrincipalcharacteristicsofmultiplexingequipmentforthesynchronousdigitalhierarchyG.780–G.789OtherterminalequipmentG.790–G.799DIGITALNETWORKSG.800–G.899DIGITALSECTIONSANDDIGITALLINESYSTEMG.900–G.999QUALITYOFSERVICEANDPERFORMANCE–GENERICANDUSER-RELATEDASPECTSG.1000–G.1999TRANSMISSIONMEDIACHARACTERISTICSG.6000–G.6999DATAOVERTRANSPORT–GENERICASPECTSG.7000–G.7999PACKETOVERTRANSPORTASPECTSG.8000–G.8999ACCESSNETWORKSG.9000–G.9999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.729.1(05/2006)iITU-TRecommendationG.729.1G.729-basedembeddedvariablebit-ratecoder:An8-32kbit/sscalablewidebandcoderbitstreaminteroperablewithG.729SummaryThisRecommendationdescribesan8-32kbit/sscalablewidebandspeechandaudiocodingalgorithminteroperablewithG.729,G.729AandG.729B.TheoutputoftheG.729EVcoderhasabandwidthof50-4000Hzat8and12kbit/sand50-7000Hzfrom14to32kbit/s.At8kbit/s,G.729EVisfullyinteroperablewithG.729,AnnexA/G.729andAnnexB/G.729.Hence,anefficientdeploymentinexistingG.729-basedVoIPinfrastructuresisforeseen.Thecoderoperateson20msframesandhasanalgorithmicdelayof48.9375ms.Bydefault,theencoderinputanddecoderoutputaresampledat16kHz.Theencoderproducesanembeddedbitstreamstructuredin12layerscorrespondingto12availablebitratesfrom8to32kbit/s.Thebitstreamcanbetruncatedatthedecodersideorbyanycomponentofthecommunicationsystemtoadjustontheflythebitratetothedesiredvaluewithnoneedforoutbandsignalling.Theunderlyingalgorithmisbasedonathree-stagecodingstructure:embeddedCode-ExcitedLinearPrediction(CELP)codingofthelowerband(50-4000Hz),parametriccodingofthehigherband(4000-7000Hz)byTime-DomainBandwidthExtension(TDBWE),andenhancementofthefullband(50-7000Hz)byapredictivetransformcodingtechniquereferredtoasTime-DomainAliasingCancellation(TDAC).Amendment1introducesthenewAnnexAcontainingtheRTPpayloadformat,capabilityidentifiersandparametersforsignallingofG.729.1capabilitiesusingH.245.BothformatandcapabilityparametersarefullycompatiblewiththecorrespondingG.729.1RTPdefinitionstoallowseamlessinteroperability.BesidesthenewAnnex,Amendment1toG.729.1incorporateschangesneededtocorrectdefectsinG.729.1andprovidesnew,morecomprehensivetestvectors.Amendment2introducesthenewAnnexB,whichdefinesanalternativeimplementationoftheG.729.1algorithmusingfloatingpointarithmetictobeusedforimplementationonDSPhardwareoptimizedforfloating-pointoperations.TheaccompanyingfloatingpointC-codeisfullyinteroperablewiththefixed-pointC-code.SourceITU-TRecommendationG.729.1wasapprovedon29May2006byITU-TStudyGroup16(2005-2008)undertheITU-TRecommendationA.8procedure.ThiseditionincorporatesthemodificationsintroducedbyAmendment1approvedon13January2007andAmendment2approvedon13February2007.iiITU-TRec.G.729.1(05/2006)FOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationAssembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-Tstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution1.InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.Compl