video

Technicalintroduction

Videousuallyreferstothestorageformatofvariousmovingimages,suchas:digitalvideoformats,includingDVD,QuickTime,andMPEG-4;andanalogvideotapes,includingVHSWithBetamax.Videocanberecordedandtransmittedviadifferentphysicalmedia:whenthevideoisshotortransmittedbyradio,itisanelectricalsignal,andwhenitisrecordedonatape,itisamagneticsignal;thequalityofthevideoactuallyvarieswiththewayitisshotandcapturedAndstoragemethodsvary.Forexample,digitaltelevision(DTV)isadevelopedformatthathashigherpicturequalitythanpreviousstandardsandisbecominganewstandardfortelevisionbroadcastinginvariouscountries.IntheUnitedKingdom,Australia,andNewZealand,theterm“Video”usuallyrefersinformallytovideorecordersandvideotapes,anditsmeaningcanbejudgedbythecontextofthearticle.

Videotechnologywasfirstdevelopedfromthecreationofthecathoderaytubetelevisionsystem,butlatertheinventionofnewdisplaytechnologymadethescopeofvideotechnologyevenlarger.TV-basedstandardsandcomputer-basedstandardshavetriedtodevelopvideotechnologyfromtwodifferentaspects.Thankstotheimprovementofcomputerperformance,andwiththebroadcastingandrecordingofdigitalTV,thesetwofieldshaveanewintersectionandconcentration.

ComputerscandisplayTVsignals,videofilesandstreamingmediabasedonmoviestandards.ComparedwithTVsystemsthatareapproachingtheirtwilightyears,computershaveincreasedtheircomputingspeedandstoragecapacity.Withthegradualpopularityofbroadband,general-purposecomputershavetheabilitytocollect,store,editandsendTVandvideofiles.

Videoproductionsoftwareiswidelyused,andthesoftwareisalsoverymuch.ZhangXiangbao,thepresidentofCurious.com,usedavarietyofvideoproductionsoftwaretocreatewonderfulspoofvideosof"ObamaKicking"and"ObamaandCameronFight",etc.,andreceivedaverylargenumberofclicksandreceivedalotofpeople'sattention.favorite.

Attributeintroduction

Pictureupdaterate

FramerateisoftentranslatedinChineseas"pictureupdaterate"or"framerate",whichreferstothevideoformatpersecondThenumberofstaticpicturesplayed.Thetypicalpictureupdateraterangesfrom6or8framespersecond(fps)intheearlydaysto120framespersecondtoday.PAL(TVbroadcastformatinEurope,Asia,Australiaandotherplaces)andSECAM(TVbroadcastformatinFrance,Russia,someAfricaandotherplaces)stipulatethattheupdaterateis25fps,whileNTSC(TVbroadcastintheUnitedStates,Canada,Japanandotherplaces)Format)stipulatesthatitsupdaterateis29.97fps.Moviefilmisshotataslightlyslower24fps;thismakesTVbroadcastsinvariouscountriesneedsomecomplicatedconversionprocedureswhenbroadcastingmovies(refertoTelecineconversion).Toachievethemostbasicvisualpersistenceeffect,aspeedofabout10fpsisrequired.

Scanningtransmission

Videocanbetransmittedbyprogressivescanningorinterlacingscanning.Interlacedscanningisamethodusedtoimprovetheimagequalitywhenthebroadcastingtechnologyisnotdevelopedintheearlyyearsandthebandwidthisverylow(itsSeeitsmainentryfortechnicaldetails).NTSC,PALandSECAMareallinterlacedscanningformats.Inshortforvideoresolution,iisoftenusedtorepresentinterlacedscanning.Forexample,theresolutionofthePALformatisoftenwrittenas576i50,where576representsthenumberofverticalscanlines,irepresentsinterlacedscan,and50represents50fieldspersecond(halfofthepicturescanlines).

Intheprogressivescansystem,allscanlineswillberefreshedeverytimethescreenisupdated.Thismethodconsumesmorebandwidthbuttheflickeringanddistortionofthepicturecanbereduced.

Inordertoconverttheoriginallyinterlacedvideoformat(suchasDVDoranalogTVbroadcasting)intoaformatacceptabletoprogressivescandisplaydevices(suchasLCDTVs,plasmaTVs,etc.),manydisplaydevicesorTheplaybackdevicehasaconversionprogram.However,duetothelimitationofthecharacteristicsoftheinterlacedscansignal,theconvertedimagecannotachievethesamequalityastheoriginalprogressivescanpicture.

Resolution

ComparingtheresolutionofvariousTVspecifications,thevideoscreensizeiscalled"resolution".Digitalvideousespixelsastheunitofmeasurement,whileanalogvideousesthenumberofhorizontalscanlinesastheunitofmeasurement.

TheresolutionofstandarddefinitionTVsignalsis720/704/640×480i60(NTSC)or768/720×576i50(PAL/SECAM).Thenewhigh-definitiontelevision(HDTV)resolutioncanreach1920×1080p60,thatis,eachhorizontalscanlinehas1920pixels,eachpicturehas1080scanlines,anditisplayedataspeedof60picturespersecond.

Theresolutionof3Dvideoisexpressedbyvoxel(volumepictureelement,translatedas"voxel"inChinese).Forexample,aresolutionof512×512×512voxelsisusedforsimple3Dvideo,whichcanbeplayedbycomputerequipmentincludingsomePDAs.

AspectRatio

Aspectratioisusedtodescribetheratioofthevideopicturetothepictureelements.TheaspectratioofthetraditionalTVscreenis4:3(1.33:1).

TheaspectratioofHDTVis16:9(1.78:1).Theaspectratioofthe35mmfilmnegativeisabout1.37:1.

Althoughthepixelsonthecomputerscreenaremostlysquare,thepixelsofdigitalvideoareusuallynot.Forexample,CCIR601,thedigitalstorageformatusedforPALandNTSCsignals,anditscorrespondingnon-equivalencewidescreenformat.Therefore,NTSCstandardDVimagesrecordedwith720x480pixelsmaybecomea4:3aspectratioscreenduetotherelatively"thin"pixelformat,orviceversabecausethepixelformatis"fat"andbecome16:9.Picture.

Colordata

U-Vcolorwheelexample,whereYvalue=0.5colorspace(ColorSpace)orcolormodel(Colormodelname)specifiesthedescriptionofcolorsinthevideo.Forexample,NTSCTVusestheYIQmodel,whilePALusestheYUVmodel,andSECAMusestheYDbDrmodel.

Indigitalvideo,theamountofpixeldata(bitsperpixel,abbreviatedasbpp)representshowmanydifferentcolorscanbedisplayedineachpixel.Duetothelimitedbandwidth,designersoftenusetechniquessuchaschromasamplingtoreducethedemandforbpp.(E.g.4:4:4,4:2:2,4:2:0).

Quality

Videoquality(ortranslatedas"imagequality","imagequality")canuseobjectivepeaksignal-to-noiseratio(PSNR)Toquantify,oruseexpertobservationtoevaluatesubjectivevideoquality.

●Forasetofvideoprocessingsystems(suchascompressionalgorithmsortransmissionsystems),atypicalsubjectiveimagequalityevaluationusuallyincludesthefollowingsteps:

●SelectagroupofunprocessedThevideoclip(calledSRC)isusedasabenchmarkforcomparison.

●Selectthesetvalueoftheprocessingortransmissionsystem(calledHRC).

●Determinethescientificmethodofhowtopresenttheprocessedvideototheevaluatorandcollectitsevaluation.

●Inviteasufficientnumberofevaluators,usuallynolessthan15people.

●Implementassessment.

●CalculatethescoresgivenbyeachevaluatortoeachgroupofdifferentHRCs(usuallyaveraged).

ManymethodsforsubjectiveimagequalityevaluationaredescribedintheITU-TRecommendationBT.500.OneofthestandardizedmethodsisDSIS(DoubleStimulusImpairmentScale).IntheDSISassessment,theevaluatorwillfirstwatchanunprocessedvideoclip,andthenwatchtheprocessedvideoclip.Finally,evaluatetheprocessedvideoclips,rangingfrom"indistinguishablefromtheoriginalimage"to"severelydegradedcomparedtotheoriginalimage."

Youkuwilllaunch150hitdramasand50exclusivedramasthatwilllandonthesatelliteTVprimefile.Youkuisnowthelargestonlinebuyeroffilmandtelevisioncopyrights.Adheringtothestrategyof"fullcoverageinthefirstround,watchingYoukuinbigdramas",Youkuwillmakethemostcomprehensivecopyrightreserveandprovidethehighestqualityviewingexperience.Intermsofquality,quantity,varietyandotherdimensions,itwillfurtherstrengthenYouku'slong-termvideointhefieldoffilmandtelevisionvarietyshows.Absolutelyleadingposition.

ZhuXiangyangsaidatthepromotionmeetingthatYoukuwillcooperatewithvariousTVstationsandprofessionalfilmandtelevisionproductioninstitutionstocomprehensivelyupgradeandexpandonthebasisof"JointPlan3.0"and"TaiwanNetworkLinkage,ProductionandBroadcastLinkage".Thebreadthanddepthofcooperationchannels.

Theadvantagesofchannel-networklinkagearemainlyreflectedinthefollowing4aspects:

1.Complementarycrowds:TVaudiencesaremainlyadultgroups,andmiddle-agedandelderlyaudiencesandhousewivesarethemainones;andTheaudienceofonlinevideoismainlyyoungpeople,andthetwopartiescaneffectivelycomplementeachother;

2.Regionalcomplementarity:TVmainlyfacesthesecondandthird-tiermarkets,andonlinevideoisdominantinthecorecitymarket;

3.Complementarybroadcasttime:TVbroadcastsaremainlyatnight,andonlinevideobroadcastsarecoveredthroughouttheday;

4.Complementarybroadcastcycles:TVdeliveryeffectsareonlyinthebroadcastinterval,andonlinevideocangivefullplaytothelong-termThetaileffectwillcontinuetobecoveredforalongerperiodoftime;Youkuwillcontinuethecooperationandwin-winrouteoflinkagebetweenthechannelandthenetworkandthelinkageofproductionandbroadcastinginthesecondhalfoftheyear,andjointlyincreasetheTVandInternetratings.Youkuwillcooperatewithfirst-tierTVstationssuchasAnhuiSatelliteTV,HunanSatelliteTV,ZhejiangSatelliteTVandDragonTVtolaunch150populardramas,including50Youkuexclusivetheaters,allofwhichareexciting.

Compressiontechnology

Videocompressiontechnology(onlyfordigitalsignals)

Sincethedigitalsignalsystemiswidelyused,peoplehavedevelopedmanymethodstocompressvideostringsflow.Sincevideodatacontainsspatialandtemporalredundancy,makinguncompressedvideostreamsisquitebadfromthepointofviewoftransmissionefficiency.

Ingeneral,spatialredundancycanbereducedby"onlyrecordingthedifferencebetweenonepartofasingleframeandanotherpart";thistechniqueiscalledintraframecompression.Anditiscloselyrelatedtoimagecompression,andtemporalredundancycanbereducedby"onlyrecordingthedifferencebetweentwoframesofdifferentpictures";thistechniqueiscalledinterframecompression,whichincludesmotioncompensationandothertechnology.Atpresent,themostcommonlyusedvideocompressiontechnologiesareMPEG-2,whichisusedinDVDandsatelliteliveTV,andMPEG-4,whichiscommonlyusedinInternettransmission.

Bittransferrate

Bittransferrate(onlyfordigitalsignals)

Bittransferrate(alsotranslatedBitrateorbitrateorbitrate)isamethodofexpressingtheamountofinformationcontainedinavideostream.Itsunitofquantityisbit/s(thenumberofbitstransmittedpersecond,alsowrittenasbps)orMbit/s(thenumberofmillionbitstransmittedpersecond,alsowrittenasMbps).Ahigherbittransferratewillaccommodatehighervideoquality.Forexample,thepicturequalityofDVDformatvideo(typicalbittransferrateis5Mbps)ishigherthanthatofVCDformatvideo(typicalbittransferrateis1Mbps).TheHDTVformathasahigher(approximately20Mbps)bittransferrate,andthereforehasahigherpicturequalitythanDVD.

Variablebitrate(VBRinabbreviation)isameansofpursuingtheimprovementofvideoqualityandreducingthebittransmissionrateatthesametime.VBR-encodedvideowillautomaticallyrecordimagesatahigherrateduringlargedynamicorcomplexframeperiods,whileatalowerrateduringstaticorsimpleframeperiods.Inthisway,thetransmissionratecanbereducedasmuchaspossiblewhileensuringaconstantpicturequality.Butforvideostreamsthathaveafixedtransmissionbandwidth,requireimmediatetransmissionandnotemporarystoragemeans,aconstantbitrate(CBR)ismoresuitablethanVBR.Videoconferencesystemisanexample.

Stereoscopic

"Stereoscopicvideo"(Stereoscopicvideo)istosendslightlydifferentvideostotheleftandrighteyesofapersontocreatethefeelingofathree-dimensionalobject.Sincethetwosetsofvideoimagesaremixedtogether,theywillfeelblurryorincorrectincolorwhenvieweddirectly.Theeffectcanonlybepresentedthroughmasksorspecialglasses.Thetechnologyinthisareaisstillevolving.Itisexpectedthatbytheendof2006,bothHDDVDandBlu-rayDiscwillhavemoviescontainingstereoscopicvideo.SeeStereoscopyand3-Dfilm.

Formatcategory

MPEG/MPG/DAT

MPEGisalsotheabbreviationofMotionPictureExpertsGroup.SuchformatsincludeavarietyofvideoformatsincludingMPEG-1,MPEG-2andMPEG-4.IbelievethatMPEG-1istheonethateveryonehasthemostcontactwith,becauseitisbeingwidelyusedintheproductionofVCDandsomenetworkapplicationsfordownloadingvideoclips.MostVCDsarecompressedinMPEG1format(theburningsoftwareautomaticallyconvertsMPEG-1to.DATformat),usingtheMPEG-1compressionalgorithm,a120-minutemoviecanbecompressedtoabout1.2GBinsize.MPEG-2isusedinDVDproduction;atthesametime,therearequitealotofapplicationsinsomeHDTV(high-definitiontelevisionbroadcasting)andsomehigh-demandvideoeditingandprocessing.UsingtheMPEG-2compressionalgorithmtocompressa120-minutemoviecanbecompressedtoasizeof5-8GB(theimagequalityofMPEG2isunmatchedbyMPEG-1).

AVI

AVI(AudioVideoInterleaved,audiovideointerleaved)isavideoandaudiointerleavedformat(videoandaudioareinterleavedforsynchronousplayback)introducedbyMicrosoft.Alow-cost,low-resolutionvideoformatonadesktopsystem.Animportantfeatureofitisscalability,anditsperformancedependsonhardwaredevices.Itsadvantageisthatitcanbeusedacrossmultipleplatforms,butitsdisadvantageisthatittakesupalotofspace.

RA/RM/RAM

RM,oneoftheaudio/videocompressionspecificationsdevelopedbyRealNetworks,RealMedia.WhatRealPlayercandoisuseInternetresourcestodealwiththeseAudio/videoconformingtoRealMedia'stechnicalspecificationsarebroadcastlive.TheRealMediaspecificationmainlyincludesthreetypesoffiles:RealAudio,RealVideo,andRealFlash(anewgenerationofhighcompressionratioanimationformatlaunchedbyRealNetworksandMacromediaincooperation).REALVIDEO(RA,RAM)formathasbeenpositionedfromtheverybeginningintermsofvideostreamingapplications.Itcanalsobesaidthatitisthecreatorofvideostreamingtechnology.Itcanrealizeuninterruptedvideoplaybackundertheconditionofdial-upInternetaccesswith56KMODEM,butitsimagequalityisworsethanthatofVCD.IfyouhaveseenthoseRMcompressedDVDs,youcanclearlycompareit.

MOV

FriendswhohaveusedMacsshouldhavebeenexposedtoQuickTimesomewhat.QuickTimewasoriginallyanimageandvideoprocessingsoftwareusedbyAppleonMaccomputers.Quick-Timeprovidestwostandardimageanddigitalvideoformats,whichcansupportstaticPICandJPGimageformats,dynamicMOVbasedonIndeocompression,andMPGvideoformatbasedonMPEGcompression.

ASF

ASF(AdvancedStreamingformat).ASFisafilecompressionformatdevelopedbyMICROSOFTinordertocompetewithRealplayerthatcandirectlywatchvideoprogramsontheInternet.ASFusestheMPEG4compressionalgorithm,thecompressionrateandimagequalityareverygood.BecauseASFexistsinavideo"streaming"formatthatcanbewatchedinstantlyontheInternet,itisnotsurprisingthatitsimagequalityisalittlebitworsethanthatofVCD,butitisbetterthantheRAMformatofthesamevideo"streaming"format.

WMV

Atechnicalstandardforreal-timedisseminationofmultimediaontheInternetindependentoftheencodingmethod.MicrosofthopestouseittoreplacetechnicalstandardssuchasQuickTime,WAVandAVI.Fileextension.ThemainadvantagesofWMVare:scalablemediatypes,localornetworkplayback,scalablemediatypes,streamprioritization,multi-languagesupport,scalability,etc.

nAVI

IfyoufindthattheoriginalplaybacksoftwaresuddenlycannotopenAVIfilesinthisformat,thenyouhavetoconsiderwhetheryouhaveencounterednAVI.nAVIistheabbreviationofNewAVI,anewvideoformatdevelopedbyanundergroundorganizationcalledShadowRealm.ItisamodificationoftheMicrosoftASFcompressionalgorithm(nottheAVIasimagined).Thevideoformatpursuesnothingmorethancompressionrateandimagequality.Therefore,inpursuitofthisgoal,NAVIhasimprovedsomeoftheshortcomingsoftheoriginalASFformat.LetNAVIhaveahigherframerate.ItcanbesaidthatNAVIisanimprovedASFformatthatremovesthecharacteristicsofthevideostream.

DivX

Thisisanothervideoencoding(compression)standardderivedfromMPEG-4,alsoknownastheDVDripformat,whichusestheMPEG4compressionalgorithmAtthesametime,itintegratesallaspectsofMPEG-4andMP3technology.Toputitbluntly,itusesDivXcompressiontechnologytocompressthevideoimageoftheDVDdiscwithhighquality,whileusingMP3orAC3tocompresstheaudio,andthensynthesizethevideoandaudio.Andaddthecorrespondingexternalsubtitlefiletoformthevideoformat.ItspicturequalityisclosetoDVDanditsvolumeisonlyafractionofthatofDVD.Thiskindofencodingdoesnothavehighrequirementsonthemachine,soDivXvideoencodingtechnologycanbesaidtobeanewvideocompressionformatthatposesthegreatestthreattoDVD,knownastheDVDkillerorDVDterminator.

RMVB

ThisisanewvideoformatextendedfromtheRMvideoformatupgrade.ItsadvancedpointisthattheRMVBvideoformatbreakstheaveragecompressionsamplingoftheoriginalRMformat.Inthisway,thebitrateresourcesarereasonablyusedonthebasisofensuringtheaveragecompressionratio.Thatistosay,sceneswithfewstaticandmotionscenesuselowercodingrates,whichcanleavemorebandwidthspace,andthesebandwidthswillappearItisusedforsceneswithfastmovingpictures.Inthisway,onthepremiseofensuringthequalityofthestillpicture,thepicturequalityofthemovingpictureisgreatlyimproved,sothatadelicatebalanceisreachedbetweenthepicturequalityandthefilesize.Inaddition,comparedtotheDVDripformat,RMVBvideoalsohasobviousadvantages.ADVDmoviewithasizeofabout700MB,ifitistranscribedintothesameaudiovisualqualityRMVBformat,itssizeisonlyabout400MBatmost.Notonlythat,thisvideoformatalsohasuniqueadvantagessuchasbuilt-insubtitlesandnoplug-insupport.Ifyouwanttoplaythisvideoformat,youcanuseRealOnePlayer2.0orRealPlayer8.0plusRealVideo9.0orhigherversiondecodertoplay.

FLV

FLVisanewvideoformatdevelopedwiththeintroductionofFlashMX,itsfullnameisFlashvideo.Itwasdevelopedonthebasisofsorenson'scompressionalgorithm.

Becauseofitsextremelysmallfilesizeandextremelyfastloadingspeed,itispossibletowatchvideofilesontheInternet.ItsappearanceeffectivelysolvestheproblemthattheexportedSWFfileisbulkyafterthevideofileisimportedintoFlash.Disadvantagessuchasgooduseonthenetwork.Allonlinevideositesusethisvideoformat.SuchasSinaPodcast,56,Youku,Tudou,Ku6,Ditu,YouTuBe,etc.,withoutexception.

F4V

F4VisastreamingmediaformatthatsupportsH.264aftertheFLVformatlaunchedbyAdobeinordertomeetthehigh-definitionera.ThemaindifferencebetweenitandFLVisthattheFLVformatusesH.263encoding,whileF4VsupportsH.264encodedhigh-definitionvideowithabitrateupto50Mbps.

Mainstreamvideosites(suchasQiyi,Tudou,Cool6)andothersiteshavebeguntouseH.264-encodedF4Vfiles,H.264-encodedF4Vfiles,underthesamefilesize,theresolutionObviouslybetterthanOn2VP6andH.263encodedFLV.MostofthevideosreleasedbyTudouand56areF4V,butthedownloadsuffixis​​FLV,whichisalsooneofthefeaturesofF4V.

MP4

MP4(MPEG-4Part14)isacommonmultimediacontainerformat,whichisbasedon"ISO/IEC14496-14"ThedefinitioninthestandarddocumentispartofMPEG-4andisanimplementationofthemediaformatdefinedinthe"ISO/IEC14496-12(MPEG-4Part12ISObasemediafileformat)"standard.ThelatterdefinesAcommonmediafilestructurestandard.MP4isacontainerformatwithamorecomprehensivedescription.Itisconsideredthatanyformofdatacanbeembeddedinit.Variousencodedvideosandaudiosarenotaproblem.However,mostofourcommonMP4filesarestoredinAVC(H.264)orMPEG-4(Part2)encodedvideoandAACencodedaudio.TheofficialfileextensionoftheMP4formatis".mp4",andthereareothermp4-basedextensionsorreducedversionsoftheformat,including:M4V,3GP,F4Vetc.

3GP

Thestreamingvideofileformatformulatedby3GPP(3rdGenerationPartnershipProject)ismainlydevelopedtomatchthehightransmissionspeedof3Gnetworks,Isalsothemostcommonvideoformatinmobilephones.

AMV

Aspecialvideoformatformp4.

Encoding

Commonvideoencoding:

1,MicrosoftRLE

An8-bitencodingmethod,whichcanonlysupportupto256colors.Compressedanimationsorcomputer-synthesizedimagesandothermaterialswithlargeareasofcolorblockscanbeencodedusingit,whichisalosslesscompressionscheme.

2,MicrosoftVideo1

Itisusedtocompressanalogvideo.Itisalossycompressionschemewithamaximumof256colors.Thequalitycanbeimagined,generallydon'tuseittoencodeAVI.

3,MicrosoftH.261/H.263/H.264/H.265

Codecforvideoconferencing,ofwhichH.261isapplicableForISDNandDDNlines,H.263issuitableforlocalareanetworks,butthiskindofCodecongeneralmachinesisusedforplaybackandcannotbeusedforencoding.

4,IntelIndeoVideoR3.2

AllWindowsversionscanuseIndeovideo3.2toplayAVIencoding.IthasahighercompressionratiothanCinepak,butthecomputerthatneedstobeplayedbackisfasterthanCinepak.

5,IntelIndeoVideo4and5

Thecommononesare4.5and5.10,thequalityisbetterthanCinepakandR3.2,andcanadapttodifferentBandwidthnetwork,butyoumusthavethecorrespondingdecodingplug-intosmoothlyplaythedownloadedworks.ItissuitableformachinesequippedwithIntelMMXorhigherCPU,andtheplaybackeffectisexcellent.IfyoumustuseAVI,itisrecommendedtouse5.10.Undertheconditionofalmostthesameeffect,ithasfasterencodingspeedandhighercompressionratio.

6,IntelIYUVCodec

Theimagequalityobtainedbythismethodisexcellent,becausethismethodchangestheordinaryRGBcolormodetoamorecompactYUVcolormode.IfyouwanttocompressAVIintoMPEG-1,theeffectyougetwithitisideal,butthegeneratedfileistoobig.

7,MicrosoftMPEG-4Videocodec

Therearethreecommonversions1.0,2.0,and3.0,ofcoursebasedonMPEG-4technology.Amongthem,3.0cannotbeusedforAVIencoding,butcanonlybeusedtogenerateASFfilesthatsupport"videostreaming"technology.

8,DivX?-MPEG-4Low-Motion/Fast-Motion

ItisactuallyequivalenttoMicrosoftMPEG-4Videocode,butLow-Motionusesafixedbitrate,whileFast-Motionusesadynamicbitrate.TheAVIcompressedbythelatterisalmosthalfthesizeoftheformer,butthequalityisworse.Low-MotionissuitableforconvertingDVDstoensurebetterpicturequality,andFast-MotionisusedforconvertingVCDstoreflecttheadvantagesofMPEG-4'scompactness.

9,DivX3.11/4.12/5.0

Infact,DivXisactuallyDivX.DivXwasoriginallydevelopedtobreakMicrosoft’sASFspecifications.ThedevelopmentteamhasbecomeDivxnetworks,sowecontinuetointroducenewversions.Thebiggestfeatureisthatthe1-passand2-passsettingsareaddedtotheencodingprogram.2-passisequivalenttotwoencodingstomaximizethenetworkbandwidthandvisualeffects.Tostrikeabalance.

Formatconversion

Commonvideoformatsarenothingmorethantwocategories:

1.Videoformat(Video)

2.Streamingmediaformat(StreamVideo).

Intheimageformatcanalsobedividedintothreetypesaccordingtothesource:

1.AVIformat:ThisisproposedbyMicrosoftandhasA"longhistory"videoformat

2.MOVformat:ThisisavideoformatproposedbyApple.

3.MPEG/MPG/DAT:ThisisacodedvideoformatjointlydevelopedbytheInternationalStandardsOrganizationISO(InternationalStandardsOrganization)andIEC(InternationalElectronicCommittee).MPEGisaninternationalstandardformovingimagecompressionalgorithmsandisnowsupportedbyalmostallcomputerplatforms.

Instreamingmediaformats,itcanalsobedividedintothreetypes:

1.RMformat:ThisisanewstreamingvideofileformatdevelopedbyRealNetworks.

2.MOVformat:MOVcanalsobeusedasastreamfileformat.QuickTimecanprovidereal-timedigitalinformationflow,workflowandfileplaybackfunctionsthroughtheInternet.Inordertoadapttothisnetworkmultimediaapplication,QuickTimeprovidescorrespondingQuickTimeViewerplug-ins(Plug-in)foravarietyofpopularbrowsersoftware.Real-timeplaybackofmultimediadatainthebrowser.

3.ASFformat:ItisastreamingmediaformatdevelopedbyMicrosoftCorporation.Itisatechnicalstandardforreal-timemultimediadisseminationontheInternet.

Ifyouwanttolearnmoreabouttheinformationofvariousvideoformats,youcanrefertotherelevantinformation,thisarticlewillnotexplainindetail.

Understandingthemainvideoformats,let’stalkaboutvideoformatconversion.Theproblemismuchsimpler.Infact,It'sjustthemutualconversionoftheaboveseveralvideoformats.

Commonvideoformatconversionsare:

DAT->MPEG1

AVI->MPEG1

DVD->MPEG4

DVD->MPEG2

MPEG->RM

MPEG->ASF

MPEG1->MPEG2

MPEG4->MPEG2

MPEG1->MPEG4

MPEG->MOV

WMV->MP4

WMV->3GP

DevelopmentLibrary

Commonvideodevelopmentlibrary:

FFMPEG:

Awell-knownforeignvideodevelopmentlibrary

CXDVA:

Comprehensivesupportforallvideoformatsmentionedabove,canbeperformedonmultipleplatformssuchaswindows,linux,android,appleios,etc.Play,capture,videoandotherfunctions,thedevelopmentinterfaceisunified,easytouse.

Displaystandard

Newdigitalvideo:

ATSC(AdvancedTelevisionSystemsCommittee),availableinNorthAmerica

DVB(DigitalVideoBroadcasting),usedinEurope,SoutheastAsia,Africa,SouthAmerica

ISDB(IntegratedServicesDigitalBroadcasting),usedinJapan

AnalogVideo:

MAC(Europe-obsolete)

MUSE(JapaneseanalogyHDTV)

NTSC(NorthAmerica,partofSouthandCentralAmerica,Japan,Taiwan)

PAL(Europe,Asia,Australia)

PALplus(Europe),thisisthePALextensionstandard

PAL-M(Brazil),ThisisavariantofPAL

SECAM(France,theformerSovietUnion,CentralAfrica)

Videoterminalstandard

AVterminal(1setofRCAorBNC)

Componentterminal(3setsofRCAorBNC)

Dterminal(IntegratedcomponentterminalestablishedbyJapaneseIndustrialStandards)

Sterminal(SstandsforSeparateVideo,1setofmini-DINterminals)

SCART(commonlyusedinEurope)

DVI(digitalvideoterminalusedbycomputermonitors).HDCPisanoption

HDMI(digitalaudioandvideoterminalusedinnewdigitalhomeappliances).HDCPisamandatoryfunction

RFterminal(RFisshortforRadioFrequency,usuallycoaxialcable,inthefollowingforms)

BNC(BayonetNiell-Concelmanconnector)

Cterminal(Concelmanconnector)

GRterminal(GeneralRadioconnector)

Fterminal(commonlyusedinU.S.residentialTVwiring)

IEC169-2(mostcommonintheUnitedKingdom)

Nterminal(Niellconnector)

TNCterminal(ThreadedNiell-Concelmanconnector)

UHFterminal(suchasPL-259/SO-239)

SDIandHD-SDI(SerialDigitalInterface)

VGAterminal(DB-9/15pin,oneofthestandardcomputerscreenterminals)

[Analogtapeformat(seeanalogTV)]

Amex

VERA(BBCexperimentalimplementation,1958)

U-matic(Sony)

Betamax(Sony)

Betacam

BetacamSP

2"Quadruplexvideotape(Ampex)

1"TypeCvideotape(AmpexandSony)

VCR,VCR-LP,SVR

VHS(JVC)

S-VHS(JVC)

VHS-C(JVC)

Video2000(PhilipsCorporation)

Video8

VideoHi8

[Digitaltapeformat(seedigitalvideo)]

D1(Sony)

D2(Sony)

D3

D4

D5HD

DigitalBetacam(Sony)

BetacamIMX(Sony)

HDV

ProHD(JVC)

D-VHS(JVC)

DV

MiniDV

MicroMV

Digital8(Sony)

[CDstorageformat]

DVD

Laserdisc(Laserdisc,MCAandPhilips)

Blu-rayDisc(Sony)

EnhancedUniversalDisc(EVD,aformatpromotedbytheChinesegovernment)

HDDVD(HitachiandToshiba)

encodingformat

CCIR601(ITU-T)

M-JPEG(ISO)

MPEG-1(ISO)

MPEG-2(ITU-T+ISO)

MPEG-4(ISO)

H.261(ITU-T)

H.263(ITU-T)

H.264/MPEG-4AVC(ITU-T+ISO)

H.265

VC-1(SMPTE)

Ogg-Theora

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