一种面向窄带环境的远程屏幕同步方法

ISSN1000-9825,CODENRUXUEWE-mail:[e-mail],Vol.17,Supplement,November2006,pp.233−242©2006byofJournalofSoftware.Allrightsreserved.Tel/Fax:[phone]∗1+,1,2,1,11(,430074)2(,200030)ALowBandwidth-OrientedRemoteScreenSynchronizationApproachJIANGWen-Bin1+,JINHai1,GUOMin-Yi2,SHAOZhi-Yuan1,ZHUZhang-Nan11(ClusterandGridComputingLaboratory,HuazhongUniversityofScienceandTechnology,Wuhan430074,China)2(DepartmentofComputerScienceandEngineering,ShanghaiJiaotongUniversity,Shanghai200030,China)+Correspondingauthor:Phn:[phone],E-mail:[e-mail],(Suppl.):233−242.:Thispaperpresentsanapproachforremotescreensynchronizationbyapplyingtheassociationofspatio-temporalredundancyreductions(ASTR).Thetemporalredundancybetweenthecurrentchangedscreenareaandthepreviousframeistakenintoaccount.ByapplyinganimprovedSSC-APDS(SubsamplingSearchCandidatesinAdjustablePartialDistortionSearch)algorithm,thespeedoftheblockmotionestimationisincreasedobviously.Experimentalresultsapprovethatthisapproachcansavemorebandwidthintransferringthescreendataandreducetheoverheadoftheclient.IthasbeenusedinapracticalwirelessapplicationforconferenceprojectingandcooperatingnamedFreeSpeechwithgoodperformance.Keywords:temporalredundancy;server-basedcomputing;ubiquitouscomputing;remotescreensynchronization;wirelessnetwork:,,..SSC-APDS(subsamplingsearchcandidatesinadjustablepartialdistortionsearch),.,,.FreeSpeech,.:;;;;...,(server-basedcomputing,SBC).,,VNC[1],PCAnywhere[2],Netmeeting[3].∗SupportedbytheNationalNaturalScienceFoundationofChinaunderGrantNo.90412010()Received2006-03-30;Accepted2006-10-08234JournalofSoftwareVol.17,Supplement,November2006,[4−6].SBC,(remotescreensynchronization,RSS).(),,.,.,,Raw,RRE,Hextile,,.,TridiaVNC[7]ZlibZlibHex,“zlib”RawHextile,.,.,.Tight[7],,.Zlib,.().,,.OLI(optimallinearinterpolation)[8].,,.OLI,2-D(2DLI).,.[9]FCE(fastcontentexpression),,,..,.,,[10]µVNC.,,VCR(videocassetterecorder).,,.,,.,,.SBC.,,,.,,.,,.,.,ASTR(theassociationofspatio-temporalredundancyreductions).,,.,SSC-APDS[11](BME).1,:1(a),(M),,,,Hextile,TightFCE,.,.,,.,.:235VideostreamRecordingReplayingIPBBIBBP……MPEG-x,H.26x,etc.MHextile,ZlibTight,FCE,etc.Sub-regionwithmotions.ServerClient(a)Staticimageprocess(b)Traditionalvideocompression(a)(b)UpdatingNochangeACBDACompensatedblockThepreviousframeThecurrentframeSub-RegionServerBCDClientThepreviousframe(c)ASTRapproach(c)ASTRFig.1Someapproachesforscreenprocess1,,.,,MPEG-x,H.26x.,.(1(b)),,,.,,,,.,.,,,ASTR(1(c)).,(,sub-region).,.RSS,,.,ASTR,,,(sub-area),:(a)(1(c)D).,,,.,;(b)(1(c)AC).236JournalofSoftwareVol.17,Supplement,November2006..,.ASTR,,,.,,,,,;(c)(1(c)B)...,.,..3,.,.(a),;(b),(1(c));(c),,,(1(c)).,,.,,,.(a),.(b),.(c),,,.,,,.,,.,,,.,SSC-APDS,BME,.2SSC-APDS,(16×16).,BMESAE.2BME:A,A,Ap,A,ASAE.ApAA.,.BME,[11−13].SSC-APDS,..,(3(a)),,.,,.,,,,.Currentframe……AApSearchareaASub-Regionwithmotions.Fig.2TheprocessofBME2BME:237…………StartpointThesearchareaRightmotionpoint……StartpointThesearchareaRightmotionpoint(a)ScanningpathinSSC-APDS(b)TheImprovementofscanningpath(a)SSC-APDS(b)Currentmacro-blockSelectedmacro-blocksfordecision(c)Macro-Blocksfordecision(c)Fig.3ImprovementoftheSSC-APDS3SSC-APDSBME,SSC-APDS,,3(c).(3(c)).:++=∑∑==mjjniiVmVnV12111111rrrλλ(1)r,V(3(b)),Vri1,.n,mVjV1ri1rVj1r.λ,λ0.5..SSC-APDS,SAE.33.1SAE,.4(a),..,(SAE0,).SAE0.(4(b)),,.4(c).:(1),;(2),,,;(3),,,;(4)(2)(3);238JournalofSoftwareVol.17,Supplement,November2006(5);(6),(1)~(5).(a)Thecaughtarea(b)Sub-Areasfound(c)Divisionofsub-areasintoregularrectangles(a)(b)(c)Fig.4Theprocessoffindingsub-areas4,.(SAE0),(SAE0).,,.(1):(,).(2):(,).,.3.2,(5).,.,.,,.(motionsofmacroblocks,thecompensatedrectangle)CompensatedrectangleOverlapPredictedrectangle(motion,location)Fig.5Reconstructionofclient5.,Zlib,.,.,,.,,,,.,.,,,BME.,.,SSC-APDS.,.:239,(Tight)ASTR.,.,.,,.,,.,.,,.,.,.4FreeSpeech[14].FreeSpeech,AdHoc,6,ManagerProviderViewer.ProviderManager,Manager.Provider.,,Manager(viewer),.,ProviderManager.VisualC++6.0,::IBM,:WindowsXP,CPU:PentiumM1.7GHz,:512MB;:Asus,:WindowsXP,CPU:PentiumM1.4GHz,:256MB;:802.11b,:11Mb/s.,10,PPT.(7).,.,S1,S2.S1,PDF150ms.,,.S2,,,.S1[9]PDF,S2WindowsXPtour.exe.,ASTRHextile,TightFCE.84.(1)(2)S1S2.,ASTR.14.S1,Hextile865KB/s,,,.TightFCE,.,ASTR,.S2,.Fig.6FreeSpeechframework6FreeSpeech240JournalofSoftwareVol.17,Supplement,November2006(a)ReadingPDFfile(b)Aflashtourplaying(a)PDF(b)flashFig.7Testscenarios794,CPU.S2,ASTRCPU,,,BME.,S1,,ASTRTightFCECPU.,BME,,,.(1)S1Bandwidthconsumption020040060080010001200140016001591317212529Time/sBandwidth(KB/s)HextileFCETightASTR(2)S2Bandwidthconsumption010020030040050060070080015913172125293337Time/sBandwidth(KB/s)HextileFCETightASTRFig.8Bandwidthconsumption8Table1Consumptionsofbandwidth(BW)andCPU1CPUHextileTightFCEASTR(KB/s)86519110958(CPU/ms)29580494421S1(CPU/ms)1112011354(KB/s)302676123(CPU/ms)89