Compressed Video Communications

1 Introduction 1 1.1 Background 1 1.2 SourceMaterial 3 1.3 Video QualityAssessmentand PerformanceEvaluation 3 1.4Outlineof the Book 6 1.5 References 9 2Overviewof DigitalVideoCompressionAlgorithms 11 2.1 Introduction 11 2.2 Why Video Compression? 12 2.3 User RequirementsfromVideo 12 2.3.1 Video qualityand bandwidth 12 2.3.2 Complexity 13 2.3.3 Synchronisation 14 2.3.4Delay 14 2.4ContemporaryVideoCodingSchemes 14 2.4.1 Segmentation-basedcoding 17 2.4.2 Model-basedcoding 19 2.4.3 Sub-band coding 21 2.4.4 Codebookvector-based codin g 23 2.4.5 Block-basedDCT transformvideo coding 24 2.4.6 NoveltiesofITU-TH.263video codingstandard 40 2.4.7 PerformanceevaluationofITU-TH.263videocodingstandard 43 2.4.8 PerformancecomparisonbetweenITU-TH.261and H.263 47 2.5 Object-based VideoCoding 54 2.5.1 VOP encoder 55 2.5.2 Shape coding 55 2.5.3 Motionestimationandcompensation 60 2.5.4Paddingtechnique 60 2.5.5 Basicmotiontechniques 61 2.5.6 Texturecoding 66 2.5.7 MPEG-4VOPdecoder 66 viii CONTENTS 2.5.8 Performance evaluation 67 2.5.9 Layered video coding 68 2.6 Conclusions 71 2.7 References 72 3 FlowControlin CompressedVideoCommunications 75 3.1 Introduction 75 3.2 BitRate Variabilityof VideoCoders 76 3.3 FixedRate Coding 79 3.4AdjustingEncoding Parametersfor RateControl 80 3.5 VariableQuantisationStep SizeRateControl 83 3.5.1 Bu?er-basedrate control 84 3.5.2 Feed-forwardratecontrol 87 3.6 ImprovedQualityRateControlUsingROICoding 90 3.7 Rate ControlUsingPrioritisedInformationDrop 94 3.8 Rate ControlUsingthe InternalFeedbackLoop 100 3.9 Reduced ResolutionRate Control 102 3.9.1 Reducedresolutionschemewith adaptiveframeratecontrol 107 3.10 Rate ControlUsingMulti-layerCoding 109 3.11 Fine Granular Scaleability 112 3.12 Conclusions 114 3.13 References 118 4 ErrorResiliencein CompressedVideoCommunications 121 4.1 Introduction 121 4.2 E?ectsof BitErrorsonPerceptualVideo Quality 122 4.3 Error ConcealmentTechniques(Zero-redundancy) 125 4.3.1 RecoveryoflostMVsandMBcodingmodes 127 4.3.2 Recoveryof lostcoe?cients 129 4.4 Data Partitioning 130 4.4.1 Unequalerrorprotection(UEP) 132 4.5 ForwardErrorCorrection(FEC)inVideoCommunications 134 4.5.1 Rate-compatiblepuncturedcodes(RCPC) 135 4.5.2 Cyclic redundancycheck(CRC) 137 4.6 DuplicateMVInformation 138 4.7 INTRA Refresh 141 4.7.1 AdaptiveINTRArefresh(AIR) 143 4.8 Robust I-frame 146 4.9 ModifiedH.263 forMobileApplications(H.263/M) 148 4.9.1 Fixedlengthcoding(FLC) 149 4.9.2 Changedorderof transmission 150 4.9.3 COD-mapcoding 150 4.9.4 Avoidingfalsesynchwordsin MVstream 151 4.9.5 Insertionofsynchwordsat fixedintervals 151 4.9.6 GOBindicatorcoding 151 4.9.7 Frametypeindicatorcoding 153 4.10 Two-wayDecodingand ReversibleVLC 153 4.11 Error-resilientEntropyCoding(EREC) 161 4.12 CombinedErrorResilienceSchemes 164 4.13 ErrorResilienceBasedon ReferencePictureSelection 168 CONTENTS ix 4.14 Conclusions 172 4.15 References 174 5 VideoCommunicationsOverMobileIPNetworks 177 5.1 Introduction 177 5.2 Evolutionof 3G MobileNetworks 177 5.3 VideoCommunicationsfroma NetworkPerspective 179 5.3.1 Whypacketvideo? 180 5.4DescriptionofFutureMobileNetworks 182 5.5 QoSIssuesfor PacketVideoover MobileNetworks 184 5.5.1 Packetisation schemes 185 5.5.2 Throughputandchannel codingschemes 188 5.6 Real-timeVideoTransmissionsoverMobileIP Networks 190 5.6.1 Packetisationofdata partitionedMPEG-4videousingRTP/UDP/IP 191 5.7 QualityOptimisationforVideo Transmissionsover MobileNetworks 196 5.7.1 Enhancedvideoqualityusingadvancederrorprotection 197 5.7.2 Content-basedadaptivequalitycontrolformobilevideotransmissions 198 5.8 PrioritisedTransportforRobustVideo TransmissionsoverMobileNetworks 200 5.9 VideoTransmissionsoverGPRS/UMTSNetworks 204 5.10 Conclusions 212 5.11 References 213 6 VideoTranscodingforInter-networkCommunications 215 6.1 Introduction 215 6.2 WhatisTranscoding? 215 6.3 HomogeneousVideo Transcoding 217 6.4Bit Rate Reduction 219 6.5 CascadedFullyDecoding/Re-encodingScheme 220 6.6 TranscodingwithRe-quantisationScheme 220 6.6.1 Picture drift e?ect 222 6.6.2 Drift-free transcoder 224 6.7 Transcodingwith MotionData Re-useScheme 226 6.8 Transcodingwith MotionData Re-estimationScheme 228 6.9 TranscodingwithMotionRefinementScheme 228 6.9.1 MV refinementalgorithm 229 6.9.2 E?ectsof refinementwindowsize ontranscodingquality 232 6.10 PerformanceEvaluationof RateReductionTranscodingAlgorithms 234 6.11 Frame Rate Reduction 234 6.12 ResolutionReduction 238 6.13 HeterogeneousVideo Transcoding 240 6.14VideoTranscodingfor Error-resliencePurposes 243 6.15 VideoTranscodingforMultimediaTra?cPlanning 248 6.16 Conclusions 252 6.17 References 252 AppendixA Layeringsyntaxof ITU-TH.263videocodingstandard 257 AppendixB DescriptionofthevideoclipsonthesupplementaryCD 265 Glossaryof Terms 270 Index 274 g 23 2.4.5 Block-basedDCT transformvideo coding 24 2.4.6 NoveltiesofITU-TH.263video codingstandard 40 2.4.7 PerformanceevaluationofITU-TH.263videocodingstandard 43 2.4.8 PerformancecomparisonbetweenITU-TH.261and H.263 47 2.5 Object-based VideoCoding 54 2.5.1 VOP encoder 55 2.5.2 Shape coding 55 2.5.3 Motionestimationandcompensation 60 2.5.4Paddingtechnique 60 2.5.5 Basicmotiontechniques 61 2.5.6 Texturecoding 66 2.5.7 MPEG-4VOPdecoder 66 viii CONTENTS 2.5.8 Performance evaluation 67 2.5.9 Layered video coding 68 2.6 Conclusions 71 2.7 References 72 3 FlowControlin CompressedVideoCommunications 75 3.1 Introduction 75 3.2 BitRate Variabilityof VideoCoders 76 3.3 FixedRate Coding 79 3.4AdjustingEncoding Parametersfor RateControl 80 3.5 VariableQuantisationStep SizeRateControl 83 3.5.1 Bu?er-basedrate control 84 3.5.2 Feed-forwardratecontrol 87 3.6 ImprovedQualityRateControlUsingROICoding 90 3.7 Rate ControlUsingPrioritisedInformationDrop 94 3.8 Rate ControlUsingthe InternalFeedbackLoop 100 3.9 Reduced ResolutionRate Control 102 3.9.1 Reducedresolutionschemewith adaptiveframeratecontrol 107 3.10 Rate ControlUsingMulti-layerCoding 109 3.11 Fine Granular Scaleability 112 3.12 Conclusions 114 3.13 References 118 4 ErrorResiliencein CompressedVideoCommunications 121 4.1 Introduction 121 4.2 E?ectsof BitErrorsonPerceptualVideo Quality 122 4.3 Error ConcealmentTechniques(Zero-redundancy) 125 4.3.1 RecoveryoflostMVsandMBcodingmodes 127 4.3.2 Recoveryof lostcoe?cients 129 4.4 Data Partitioning 130 4.4.1 Unequalerrorprotection(UEP) 132 4.5 ForwardErrorCorrection(FEC)inVideoCommunications 134 4.5.1 Rate-compatiblepuncturedcodes(RCPC) 135 4.5.2 Cyclic redundancycheck(CRC) 137 4.6 DuplicateMVInformation 138 4.7 INTRA Refresh 141 4.7.1 AdaptiveINTRArefresh(AIR) 143 4.8 Robust I-frame 146 4.9 ModifiedH.263 forMobileApplications(H.263/M) 148 4.9.1 Fixedlengthcoding(FLC) 149 4.9.2 Changedorderof transmission 150 4.9.3 COD-mapcoding 150 4.9.4 Avoidingfalsesynchwordsin MVstream 151 4.9.5 Insertionofsynchwordsat fixedintervals 151 4.9.6 GOBindicatorcoding 151 4.9.7 Frametypeindicatorcoding 153 4.10 Two-wayDecodingand ReversibleVLC 153 4.11 Error-resilientEntropyCoding(EREC) 161 4.12 CombinedErrorResilienceSchemes 164 4.13 ErrorResilienceBasedon ReferencePictureSelection 168 CONTENTS ix 4.14 Conclusions 172 4.15 References 174 5 VideoCommunicationsOverMobileIPNetworks 177 5.1 Introduction 177 5.2 Evolutionof 3G MobileNetworks 177 5.3 VideoCommunicationsfroma NetworkPerspective 179 5.3.1 Whypacketvideo? 180 5.4DescriptionofFutureMobileNetworks 182 5.5 QoSIssuesfor PacketVideoover MobileNetworks 184 5.5.1 Packetisation schemes 185 5.5.2 Throughputandchannel codingschemes 188 5.6 Real-timeVideoTransmissionsoverMobileIP Networks 190 5.6.1 Packetisationofdata partitionedMPEG-4videousingRTP/UDP/IP 191 5.7 QualityOptimisationforVideo Transmissionsover MobileNetworks 196 5.7.1 Enhancedvideoqualityusingadvancederrorprotection 197 5.7.2 Content-basedadaptivequalitycontrolformobilevideotransmissions 198 5.8 PrioritisedTransportforRobustVideo TransmissionsoverMobileNetworks 200 5.9 VideoTransmissionsoverGPRS/UMTSNetworks 204 5.10 Conclusions 212 5.11 References 213 6 VideoTranscodingforInter-networkCommunications 215 6.1 Introduction 215 6.2 WhatisTranscoding? 215 6.3 HomogeneousVideo Transcoding 217 6.4Bit Rate Reduction 219 6.5 CascadedFullyDecoding/Re-encodingScheme 220 6.6 TranscodingwithRe-quantisationScheme 220 6.6.1 Picture drift e?ect 222 6.6.2 Drift-free transcoder 224 6.7 Transcodingwith MotionData Re-useScheme 226 6.8 Transcodingwith MotionData Re-estimationScheme 228 6.9 TranscodingwithMotionRefinementScheme 228 6.9.1 MV refinementalgorithm 229 6.9.2 E?ectsof refinementwindowsize ontranscodingquality 232 6.10 PerformanceEvaluationof RateReductionTranscodingAlgorithms 234 6.11 Frame Rate Reduction 234 6.12 ResolutionReduction 238 6.13 HeterogeneousVideo Transcoding 240 6.14VideoTranscodingfor Error-resliencePurposes 243 6.15 VideoTranscodingforMultimediaTra?cPlanning 248 6.16 Conclusions 252 6.17 References 252 AppendixA Layeringsyntaxof ITU-TH.263videocodingstandard 257 AppendixB DescriptionofthevideoclipsonthesupplementaryCD 265 Glossaryof Terms 270 Index 274