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1、数字电视基础培训 Part 1有线所2005-09Confidential1内容n数字与模拟n图像压缩n数字调制基础n数字电视标准n数字电视传输体系n数字电视服务体系n小结n参考文献Confidential2数字与模拟AnalogDigital Confidential3图像压缩n为什么要进行压缩编码为什么要进行压缩编码数字复合NTSC : 143Mbps 数字复合PAL : 177Mbps数字分量ITU-R 601 : 270MbpsConfidential4图像压缩Confidential5图像压缩压缩标准：压缩标准：JPEG： Joint Picture Experts Group Mo
2、tion-JPEGMPEG：Moving Picture Experts Group MPEG-1 MPEG-2 MPEG-3 MPEG-4Confidential6图像压缩Video InCoded framesQuantizeVariable LengthCoderDCTMUXBUFFERrate controllosslessAddPass /SubtractAnchor frame storeMotion Estimationpredicetdframe storeGOP ControlMotion Vectors422 to420inverseDCTConfidential9图像压缩
3、12345678910111213I1P4B2B3P7B5B6P10 B8B9I13B11B1212345678910111213Confidential10图像压缩PES packet payloadPES packet headerAudio or Video Elementary Stream TS PacketTS Packet HeaderConfidential11图像压缩Elementary streamsVideoAudioMPEG AudioEncoderMPEG VideoEncoderInternalMultiplexerBasic Encoder FunctionSPT
4、S -Single program MPEGTransport streamsPSIMPTS -Multiple program Transport streamRemuxPSI/SIManagerOutput AdapterBasic Multiplexer FunctionSPTS -SPTS -SPTS -SPTS -DATA -Confidential12图像压缩0Channel ComplexityRelative Activity 电影新闻节目体育节目20%40%60%80%100%Relative Bandwidth allocationRelative Bandwidth al
5、location电影新闻节目体育节目Confidential13数字调制基础n信源编码的目的是提高信源的效率n信道编码的目的是增加传输的可靠性透明，对所传信息的内容没有任何限定具有与信道相适应的频谱特征效率高包含同步信息有纠错能力差错扩散度低Confidential14数字调制基础0000000100100011010001010110011110001001101010111100110111101111Confidential15数字调制基础Confidential16数字调制基础0000-0011-1001-1111-1100-0111-0101-1000-0110-0010-01000
6、000001110011111110001110101100001100010010000000011100111111100011101011000011000100100需要需要VLC等对数据的优化等对数据的优化Confidential17数字电视标准AV信源AV编码压缩码流复用信道编码调制信道解调解码AV解码AV显示Confidential18数字电视标准欧洲：DVB美国：ATSC日本：ISDB-TConfidential19数字电视传输体系n有线信道数字有线电视n无线信道数字卫星电视数字地面电视数字手持电视Confidential20数字电视传输体系数字有线电视16QAM, 32QAM
7、,64QAM,128QAM,256QAMConfidential21数字电视传输体系数字卫星电视Confidential22数字电视传输体系数字地面电视调制方式： COFDM Coded Orthogonal Frequency Division Multiplex2K：17058K：6817Confidential23数字电视传输体系数字地面电视Confidential24数字电视传输体系数字手持电视nBased on DVB-T, backwards fully compatiblenGives additional features to support Handheld portabl
8、e and mobile receptionbattery saving mobility with high data rates, single antenna reception, SFN networksimpulse noise toleranceincreased general robustnesssupport for seamless handovernThe above have been achieved by adding optionsTime-slicing for power savingMPE-FEC for additional robustness and
9、mobility4k mode for mobility and network design flexibilityplus additional minor changes, e.g., in signallingnDVB-H is meant for IP-based services via MPE insertionnDVB-H can share DVB-T multiplex with MPEG2 servicesnPortable/indoor coverage should be built to the network for fully exploit the DVB-H
10、 possibilities businesswiseConfidential25数字电视传输体系数字手持电视DVB-HPowerconsumptionis key !HConfidential26数字电视传输体系数字手持电视Based on DVB-T, can share multiplex with DVB-T servicesIP-based solution, MPE used over DVB-TNew 1: Time Slicing for power savingNew 2: MPE-FEC for mobile performance and tolerance to imp
11、ulse noise, (reuses memory of time slicing, has effectively a virtual time interleaver)New 3: features to DVB-T PHYOptional 4K mode and 4K symbol interleaver for mobility in large and medium sized SFNsOptional in-depth interleaver for 2K and 4KAdditional signalling in TPSMandatory use of cell-ID5 MH
12、z channels for non-broadcasting bandsConfidential27数字电视传输体系数字手持电视MUXMPEG-2 TV ServiceMPEG-2 TV ServiceMPEG-2 TV ServiceMPEG-2 TV ServiceMPEMPE-FECTimeSlicingDVB-HIP- EncapsulatorIP8k4k2k DVB-H TPSDVB-T ModulatorTSRFRFTransmitter8k 4k 2k DVB-H TPSDVB-T DemodulatorTSMPEMPE-FECTimeSlicingDVB-HIP- Decap
13、sulatorIPReceiverNew to DVB-HExistingChannelConfidential28数字电视传输体系数字手持电视nTime Sliced and non-Time Sliced services in common multiplexOnly receiver switched off, transmitter on all the timeSupport for Time Slicing not mandatory to receive Time Sliced servicenEven 90% power saving for the front-end ca
14、n easily be achieved.nUninterrupted service reception with single receiver hand-over.e.g. MPEG2e.g. MPEG2Confidential29数字电视传输体系数字手持电视eeeF1F2F3DVB-H IPE-Time Slicing-MPE-FECDVB-T Tx-4k capable, if neededRepeater-Repeaters may be used.IP-backboneDense SFN-FFT-size selected according the planning requi
15、rements-Some operators use 4k some 8kConfidential30数字电视服务体系Confidential31数字电视服务体系Confidential32数字电视服务体系Confidential33数字电视服务体系Confidential34数字电视服务体系Confidential35数字电视服务体系OS, drivers, firmware, .Java Virtual MachineInteroperable ApplicationTrans-portProto-col(s)DVB specificAPIsSun JavaAPIsDAVICAPIsDat
16、aHAViAPIsApplicationManager(Navigator)InteroperableApplication(and libraries)System SoftwareConfidential36数字电视服务体系Content DeliveryContent CreationContent ReceptionConfidential37数字电视服务体系数据广播数据广播音视频内容音视频内容数据内容数据内容音视频处理单元音视频处理单元数据广播子系统数据广播子系统复复 用用 器器CA/SMS系统系统网网络络接接口口传传输输网网络络用用户户接接收收端端数字电视系统数字电视系统Confi
17、dential38数字电视服务体系应应 用用MPEG-2 TS 流流数数据据管管道道数数据据流流PESMPEG-2 私有数据段私有数据段DSM-CCSectionDSM-CC数据轮播数据轮播DSM-CC对象轮播对象轮播对象轮播对象轮播多协议多协议封装封装数据轮播数据轮播Confidential39数字电视服务体系Confidential40数字电视服务体系Confidential41小结n数字电视的系统性n数字电视的综合性n数字电视的复杂性Confidential42参考文献nDVB-7.0nISO 13818nDiviCom、Alticast、DVB演示文档Confidential43Confidential44
