Transmitting Scalable Video over a DiffServ networkProject ProposalSpecificsSimulation scenarioObjective of the ProjectMUX gainGraceful degradation with lossShort Term CongestionReaction time vs.congestion durationHeavier congestionPriority dropping vs FeedbackConfiguration of AF queueRED worse than DropTailThreshold for EL(HP)Threshold for EL(LP)Effect of BL (I): on quality degradationEffect of BL (II): on thresholdsTransmission of Scalable VideoFuture work1Sangeun Han, Athina MarkopoulouTransmitting Scalable Video over a DiffServ network EE368C Project PresentationSangeun Han, Athina Markopoulou3/6/012Sangeun Han, Athina MarkopoulouProject Proposal•Problem:–Video transmission over the heterogeneous Internet •Facts:–Scalability: different parts of a video stream contribute unequally to the quality. –DiffServ Networks can provide service differentiation, based on the marking of packets.•Proposal–Limit the effect of loss when it happens. Prioritize information according to importance and drop packets accordingly.3Sangeun Han, Athina MarkopoulouSpecifics•What type of scalability? H.263+, SNR•Which DiffServ class? AF (priority dropping)E FA F 1A F 2A F 3A F 4B Ew 2w 3w 4w 5w 6b u f f e rm a n a g e m e n tp a c k e ts c h e d u l i n gh i g h s t r i c t p r i o r i t yconditioningclassificationAF11I P P PEI EP EPEPELBL4Sangeun Han, Athina MarkopoulouSimulation scenario(*) Mode A: at frame level,Total header= IP(20)+UDP(8)+RTP(12)+H.263(4)=44B(**) Freezing previous frame H.263+Encoder+LayeringRTPPacket.for H.263(*)Decoding+[ErrorConceal.] (**)Depackt.MarkerSingle AF queue,2 levels, 100KBMain stream: Foreman (10fps) 136Kbps, BL+EL, 2min10-20 Interfering StreamsBL+EL~=136Kbpsrandom parts of 6 different streams1.5MbpsLoss infoOriginal Stream5Sangeun Han, Athina MarkopoulouObjective of the Project•Show the benefit from using Priority Dropping for Scalable Video–MUX gain–Graceful Quality Degradation –Handle short term congestion•Configuration –AF queue: •buffer management, thresholds, other parameters–Layering parameters•base layer, temporal dependence•Recommendation–To Feedback or to Drop?6Sangeun Han, Athina MarkopoulouMUX gainNonlayeredLayered+PD7Sangeun Han, Athina MarkopoulouGraceful degradation with lossLayered+lossNon Layered + lossNL, no lossFGS+ data loss8Sangeun Han, Athina MarkopoulouShort Term Congestion•The source may react to congestion by adapting its transmission rate...CongestiontimeRateBLELDDtimetimeReaction with no delay D=0Reaction with Delay D>0R9Sangeun Han, Athina MarkopoulouReaction time vs.congestion duration•Simple example: –10 streams + 5 more in [55sec,65sec]–10 streams react by dropping their EL in [55+D, 65+D]10Sangeun Han, Athina MarkopoulouHeavier congestion•Heavy + non adaptive interfering traffic: –10 streams + 10 more in [55sec,65sec]–10 streams react by dropping their EL in [55+D, 65+D]11Sangeun Han, Athina MarkopoulouPriority dropping vs Feedback•Priority Dropping –is like reaction in D=0, by appropriate rate decrease–may handle non adaptive sourcesCongestiontimeRateBLELR(t)•Feedback •is limited by delay•saves network resources•requires coordination12Sangeun Han, Athina MarkopoulouConfiguration of AF queue•Choices:–Thresholds for the different priorities–Buffer management: RED or DropTail?•Observations:–Not sensitive to choice of thresholds–RED inappropriate: do not use Avg Qsize, set Lmin=Lmax–Differentiation: (I) different thresholds (II) OccupancyLow dropDropprobHigh dropBuffer occupancy10BL - low drop precedence EL - high drop precedenceL_min L_max H_min,max13Sangeun Han, Athina MarkopoulouRED worse than DropTailFor all loads….…for all thresholdsand14Sangeun Han, Athina MarkopoulouThreshold for EL(HP) •By assigning the buffer thresholds –we control the Queue Occupancy for BL, EL Threshold_HDP = 56 Threshold_HDP = 1615Sangeun Han, Athina MarkopoulouThreshold for EL(LP) •…this way we distribute the loss among BL and EL•….and thus the quality•Insensitive to:•RED, DropTail•BL choice•[more sensitive to load]16Sangeun Han, Athina MarkopoulouEffect of BL (I): on quality degradationQP(BL)=12, 1:1, (BL=64kbps:EL=74kbps)QP(BL)=15, 1:2, (BL=50kbps:EL=86kbps)QP(BL)=30, 1:4, (BL=27kbps:EL=110kbps)Same target rate: BL+EL~=136kbps17Sangeun Han, Athina MarkopoulouEffect of BL (II): on thresholdsQP(BL)=12, 1:1, (BL=64kbps:EL=74kbps)QP(BL)=15, 1:2, (BL=50kbps:EL=86kbps)QP(BL)=30, 1:4, (BL=27kbps:EL=110kbps)Same target rate: BL+EL~=136kbps18Sangeun Han, Athina MarkopoulouTransmission of Scalable Video•Use feedback + adaptation at the source to match the transmission rate with the bottleneck bandwidth, to save network resources along the path•Use Priority Dropping to handle short term congestion QualityRatePDlossFeedbackBL1BL219Sangeun Han, Athina MarkopoulouFuture work•Improvements needed–realistic feedback + adaptation–>2 layers–finish FGS•New experiments needed–Delay aspect:•Loss at the playback buffer •Entire streams having different delay requirements –Multiple hops–Single wireless hop (802.11 + QoS)–Video + Data–Larger Bandwidths–Other types of scalability: FGS, Temporal, Spatial,