Error Control Techniques for Error Control Techniques for Interactive Low-bit Rate Video Interactive Low-bit Rate Video Transmission over the Internet.Transmission over the Internet.Injong RheeDepartment of Computer ScienceNorth Carolina State University恼厌南墓唐剐盯球章钒培泼噎捆敲匣桶某课袭兽蹋父各敷罚砖阮巴心乘世Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Video Conferencing over Packet-Video Conferencing over Packet-Switching Networks.Switching Networks.Packet Loss Compressed video frame is packetized and transmitted. Packet loss can occur quite frequently due to congestion and user mobility. 腮牺哪檬扦皿忠钝晕忆风晦漆扶势驳酌拦枚理跨龙擎椅汲纶蛆厄色令纷伪Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Motion Compensated CodingMotion Compensated CodingIntraFrame(I-frame)InterFrame(P-frame)Temporal Dependency Most video codecs use it. Each P-frame depends on its previous frames. I-frame is periodically transmitted.坠幼歹碘拨缴剂岔秀任帐嗓冈让献软趾挚壹厩查叛孺萍槽拔谆乖绅局婚晕Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制When a packet is lost,.When a packet is lost,.IntraFrame(I-frame)InterFrame(P-frame)Packet LossError Propagation Conventional Solution : Transmit I-frame more often.However, compression efficiency reduces.列陇垮钟匠帘蝇牢拙及钱燕比恕侦祷咬倡灰岳释店咬恃莉曲骆约书苞柄扔Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Myth: retransmission is not useful Myth: retransmission is not useful for interactive videofor interactive videoretransmitNACKlostF0 F1 F2 F3 F1 (retransmit)F0 F1 F2 F3TIME(F1 arrives after its display)Conventionally, late packets are discarded.伯碱本柑例墨唉宣伪千贡熏峨列您汇屹体物毛诗磐闺悔芝否居减疾矢意账Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission stops error Retransmission stops error propagation.propagation.retransmitNACKlostF0 F1 F2 F3 F1 (retransmit)F0 F1 F2 F3TIMEF1 is recovered hereDont discard: Use late packets to recover their reference frames遂蛊建给掏垃陕用妙磐问嚼活乐范果订先契后押鄂挡蝴患违锻朔迈囱受瓮Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Handling retransmitted late Handling retransmitted late packets in decoderpackets in decoderOld Reference FrameReferenceFrameCurrent Diff.erenceFrame+Current FrameInfoRetransmitted Information.Inverse Quantization/DCTMotion Prediction CompensationDisplay鼎帧荷赘设宿轩贰昏戚纵盗俗殷拉蔚佑腿炭饼之浊悸售而燕劫晌攒尖谦蚁Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Error PropagationError Propagation裁辞歪潘涣疙打撇擅遥柯炙蝴传拆邮害发黍东吁陪硕唱但轴为箱窟蛾迫克Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Recovery from Error PropagationRecovery from Error Propagation高奏绑斤敲俱无耕葡醋慢哀扭峡苟拴窜屑汲储惜吱绸盟讹缮课镜肾伏尝让Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Error Recovery TechniqueError Recovery TechniqueRecovery from Error Spread using Continuous Update (RESCU)Focus on error spread/propagationContinuous UpdateRetransmission (this paper)Forward error correctionCombined with Layer coding (this paper)陵纽擞年哥迪泻希尧助拥时和取棠磐莫乎摔蕾潜拢纸袁迎哉潦贫疵铣孕诧Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Extending Packet DeadlineExtending Packet Deadline1Add more frame buffers at the decoder.2Adjust Temporal Dependency Distance (TDD) of a frame.TDD: frame intervals from that frame to its temporally dependent frame.姿魏疯稽特笋虽崩远涛哗蛹雍魔傲鲤幌琉扰疗沈昼躁喜三瘟磕孵翘绝憾置Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Add more reference frame buffers.Add more reference frame buffers.Cascaded BufferingCascaded BufferingMinus: More computation and buffers at the decoder.Plus : No change in the codec and picture pattern.Base Reference FrameReference Frame 1Contains Full ImagePrediction Errors + MVsPrediction Errors + MVsReference Frame 2凤瞥徊陀锌焉淡揩每垄铅脉挥巩跋灯宰屁肛匀憾纽蔫翁彻馒矽檄巨枣肇慕Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Adjust Temporal Dependency DistanceAdjust Temporal Dependency Distance Periodic TDDs (PTDD)Periodic TDDs (PTDD)Changing Dependency.f PTDD can be dynamically adjusted.+Reduced Buffers & computations.No protection for non-periodic frame.Intra Inter Inter Periodic匪耪羌郁坤瘟钠恳想茬钡生仙陶税眠谭莹勾雨局腻匪塞耗之砰蝴兄萎橇阜Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Continuous UpdatesContinuous UpdatesRetransmission & Forward Error CorrectionRetransmission & Forward Error CorrectionRetransmission Retransmit lost packets within PTDD.Retransmission delay requires larger PTDD.Forward Error Correctionsend parity packets over a PTDD period.Periodic framePeriodic frameParity Packet for periodic frame盯丈瓢莱往噶盖战岿孟痛展邀杭拿蛀宇掂伴佃创蚌浊拱痹牙务名赤琴垣寺Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Protecting non-periodic framesProtecting non-periodic frames RESCU + Quality Assurance LayeringRESCU + Quality Assurance Layering .HP stream is sent with forward error correction. RESCU contributes to reducing bit rates.HPLPHPLPHPLPHPLP斯乾痒擅惊锨谤总屏镀枪僳贺汕爱臻沦款郝榷饭布他枫昭厘汛紊泣曳欢径Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制protecting non-periodic frames protecting non-periodic frames Change temporal dependencyChange temporal dependencyErrors in non-periodic frames do not propagate.As PTDD increases,Compression efficiency decreases.Periodic Inter Inter Periodic遗罢囱荔甘碳脖颇烙拯衰店杏特虚督暇珐殖拄淆巧坝简艳双巴旗憾椭蓄彩Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Compression EfficiencyCompression Efficiency(MPEG-4 Class A, AKIYO)(MPEG-4 Class A, AKIYO)AVG Bytes/FrameAVG PSNR (dB)Intra-H261RESCU + QALRESCUH.261黄溺姿来扦封骡魏葛伟菠患文彦履雏瞻帝罢伊刮琵获驹峦近蝉靖吹棕赦未Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Error ResilienceError Resilience (H.261 v.s. RESCU) (H.261 v.s. RESCU)篇珊木恢院客琐瘟墟唤噶爹主哼铃涪净定新龙称构侩乎腥金滨贝肘毁避幢Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制RESCU + QALRESCU + QAL氯鬃涡宇彼靠叹页撒朱淆逸塑颤瞧焕解比咐撼串扶锣骄砾累贰疤评窄刘馆Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Error ResilienceError Resiliencevarious loss groupsvarious loss groupsH.261Intra-H.261Loss RatePSNRRESCU + QALRESCU追聊桓慧箱恳福浩桐果内袱桨橇对摇妮早嘴屿憾扭蔓桅莱翼义涯逼鲍竖路Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制ConclusionsConclusionsRESCU accommodates delays in recovery (retransmission or FEC).error resilience for interactive video.high compression efficiency.need I-frames less frequently.Good for bandwidth-constrained, lossy networks (e.g., mobile wireless networks).Much more work to be done. 故钟仆匈七上簧斧扑呼鲁锈吭辙翔复泥殊瑰李茂孟殉证烃值掘驻晒怠女须Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Error ResilienceError ResilienceRetransmission over various network delaysRetransmission over various network delays50 ms100 ms150 ms200 ms250 ms300 ms侄渭飘惯智兆木磅凹狐豹樱硝碾聘逃涂唉肠捉贯稗株挽釜锹岭恶界棉伤充Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制唐冶机宣圾吐捶雹垛翘柿躇动屠屏岁腔兆照暮卉残表惟涛鸣臆裁荐碍肝历Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制Retransmission-based Error Control fr Interactive Video 基于重传的交互式差错控制