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【英文标准名称】:Commoninterfacespecificationforconditionalaccessandotherdigitalvideobroadcastingdecoderapplications
【原文标准名称】:条件存取和其它数字视频广播译码器用通用接口规范
【标准号】:BSEN50221-1997
【标准状态】:现行
【国别】:英国
【发布日期】:1997-08-15
【实施或试行日期】:1997-08-15
【发布单位】:英国标准学会(BSI)
【起草单位】:BSI
【标准类型】:()
【标准水平】:()
【中文主题词】:传送层;广播;界面;开放系统互连;对话层;应用层(开放系统互连);物理层(开放系统互连);数据链路层;电视接收机;数字信号;译码;目标(数据处理);视频信号;编码(数据转换)
【英文主题词】:
【摘要】:Asetofstandardshasbeendesignedtobeusedindigitalvideobroadcasting.Thesestandardsincludesourcecoding,channelcoding,serviceinformationanddecoderinterfaces.Inaddition,aconditionalaccesssystemisusedwhenthereisaneedtocontrolaccesstoabroadcastservice.Ithasbeendecidedthattheconditionalaccesssystemneednotbestandardised,althoughacommonscramblingalgorithmisprovided.Itremainsforbroadcasterstoaccessdecoderswithdifferentconditionalaccesssystemsandtoensurethattheyhavechoiceofsupplyofsuchsystems.Asolutionistousethecommonscramblingalgorithmandtoexecutesolutionsforaccessbasedoncommercialagreementsbetweenoperators.ThissolutioncanoperatewithsingleCAsystemsembeddedindecoders.AsecondsolutionisbasedonastandardisedinterfacebetweenamoduleandahostwhereCAandmoregen-erallydefinedproprietaryfunctionsmaybeimplementedinthemodule.Thissolutionalsoallowsbroadcasterstousemodulescontainingsolutionsfromdifferentsuppliersinthesamebroadcastsystem,thusincreasingtheirchoiceandanti-piracyoptions.Thescopeofthisdocumentistodescribethiscommoninterface.Thedecoder,referredtointhisspecificationasthehost,includesthosefunctionsthatarenecessarytoreceiveMPEG-2video,audioanddataintheclear.ThisspecificationdefinestheinterlacebetweenthehostandthescramblingandCAapplications,whichwilloperateonanexternalmodule.Twologicalinterfaces,tobeincludedonthesamephysicalinterface,aredefinedThefirstinterfaceistheMPEG-2TransportStream.ThelinkandphysicallayersaredefinedinthisspecificationandthehigherlayersaredefinedintheMPEG-2specifications.Thesecondinterface,thecommandinterface,carriescommandsbetweenthehostandthemodule.Sixlayersaredefinedforthisinterface.Anexampleofasinglemoduleinconnectionwithahostisshowninfigure1.Thisspecificationonlydefinesthoseaspectsofthehostthatarerequiredtocompletelyspecifytheinteractionsacrosstheinterface.Thespecificationassumesnothingaboutthehostdesignexcepttodefineasetofserviceswhicharerequiredofthehostinordertoallowthemoduletooperate.Thespecificationdoesnotdefinetheoperationorfunctionalityofaconditionalaccesssystemapplicationonthemodule.Theapplicationswhichmaybeperformedbyamodulecommunicatingacrosstheinterfacearenotlimitedtoconditionalaccessortothosedescribedinthisspecification.Morethanonemodulemaybesup-portedconcurrently.
【中国标准分类号】:L70
【国际标准分类号】:33_170
【页数】:92P;A4
【正文语种】:英语