《计算机专业英语》-Unit8MultimediaTechnology

TextA:MultimediaApplication下一页返回TextA:MultimediaApplication1.ComputerAnimationSometypicalapplicationsofcomputergeneratedanimationareentertainstudies,trainingandeducation.Althoughwetendtothinkofanimationasimplyingobjectmotions,thetermcomputeranimationgenerallyreferstoanytimesequenceofvisualchangesinascene.Inadditiontochangingobjectpositionwithtranslationsofrotations,acomputergeneratedanimationcoulddisplaytimevariationsinobjectsize,color,transparencyorsurfacetexture.Advertisinganimationsoftentransformoneobjectshapeintoanother.Andwecanproducecomputeranimationsbychanginglightingeffectsorotherparametersandproceduresassociatedwithilluminationandrendering.上一页下一页返回TextA:MultimediaApplicationManyapplicationsofcomputeranimationrequirerealisticdisplays.Anaccuraterepresentationoftheshapeofathunderstormorothernaturalphenomenadescribedwithanumericalmodelisimportantforevaluatingthereliabilityofthemodel.Also,simulatorsfortrainingaircraftpilotsandheavyequipmentoperatorsmustproducereasonablyaccuraterepresentationsoftheenvironment.Entertainmentandadvertisingapplications,ontheotherhand,aresometimesmoreinterestedinvisualeffects.Thus,scenesmaybedisplayedwithexaggeratedshapes,unrealisticmotionsandtransformations.上一页下一页返回TextA:MultimediaApplicationTherearemanyentertainmentandadvertisingapplicationsthatdorequireaccuraterepresentationsforcomputergeneratedscenes.Andinsomescientificandengineeringstudies,realismisnotgoal.Forexample,physicalquantitiesareoftendisplayedwithpseudocolorsorabstractshapesthatchangeovertimetohelptheresearcherunderstandthenatureofthephysicalprocess.上一页下一页返回TextA:MultimediaApplication2.DesignofAnimationSequencesIngeneral,ananimationsequenceisdesignedwiththefollowingstepsStoryboardlayoutObjectdefinitionsKeyframespecificationsGenerationofinbetweenframes上一页下一页返回TextA:MultimediaApplication3.VideoEditorandVideoEditingVideoeditorisacomputerthatcontrolstwovideotaperecorderstoallowanoperatortoplaybacksequencesfromoneandrecordtheseonthesecondmachine.ItsynchronizesthesequencesusingSMPIEtimecodesorbycountingframesorbyusinganEDLthathasbeenproducedwithanofftimeeditingsoftwarepackage.Videoeditingisamethodofeditingavideosequenceinwhichthevideoisdigitizedandstoredinacomputer;theeditorcanthencutandmoveframesinanyorderbeforeoutputtingthefinishedsequence.Thefinishedsequencecaneitherberecordeddirectlyfromthecomputeroutput(butthisisnormallyatalowerqualitythantheoriginalduetocompressionloss)orthecomputercanoutputtimecodeinstructionsthatcanbethenusedwithaneditingsuitedtoedittheoriginalvideotape.上一页下一页返回TextA:MultimediaApplication4.VideoConferencingThisisamethodusedtoallowpeopleatremotelocationstojoininaconferenceandshareinformation.Originally,donewithanalogvideoandexpensivesatellitelinks,videoconferencingisnowperformedwithcompresseddigitalvideotransmittedoveralocalareanetworkortheInternet.Fromanapplicationstandpoint,videoconferencinghasgonewaybeyondlookingatapictureofaperson;userscanlookatandupdatecharts,makedrawings,andsoon,allonline.AvideocameraandaspeakerphonearelinkedtoaPCwhichinturnislinkedtothenetwork.上一页下一页返回TextA:MultimediaApplicationWordsandExpressionsapproach:n.方法digitize:v.数字化duplicate:v.复制illumination:n.照明instruction:n.指令intermediate:adj.中间的intricate:adj.复杂的，错综的parameter:n.参数，参量上一页下一页返回TextA:MultimediaApplicationpolygon:n.多角形，多边形pseudo:adj.假的，伪的realistic:adj.逼真的rotation:n.旋转simulator:n.模拟软件sketch:n.草图soundtrack:n.声道，声迹spline:n.花键，键槽standpoint:n.立场synchronize:v.同步上一页下一页返回TextA:MultimediaApplicationtexture:n.纹理thunderstorm:n.雷暴雨transparency:n.透明度Computergenerated:计算机产生的Entertainstudies:娱乐性学习inadditionto:除……之外inresponseto:响应intermsof:根据，按照Inbetween:中间人，中间者storyboard:情节上一页下一页返回TextA:MultimediaApplicationNotes①Somekeyframesarechosenatextremepositionsintheaction;othersarespacedsothatthetimeintervalbetweenkeyframesisnottoogreat.

有些关键帧处于动作中的端值位置；而其余帧都是空白的，因此关键帧的时间间隔并不太长。②ItsynchronizesthesequencesusingSMPIEtimecodesorbycountingframesorbyusinganEDLthathasbeenproducedwithanofftimeeditingsoftwarepackage.

用SMPIE时间代码或对帧计数，或使用离线编样软件包生成EDI来使视频序列同步。上一页下一页返回TextA:MultimediaApplication③Thefinishedsequencecaneitherberecordeddirectlyfromthecomputeroutput(butthisisnormallyatalowerqualitythantheoriginalduetocompressionloss)orthecomputercanoutputtimecodeinstructionsthatcanbethenusedwithaneditingsuitedtoedittheoriginalvideotape.④Thisisamethodusedtoallowpeopleatremotelocationstojoininaconferenceandshareinformation.Originally,donewithanalogvideoandexpensivesatellitelinks,videoconferencingisnowperformedwithcompresseddigitalvideotransmittedoveralocalareanetworkortheInternet.上一页下一页返回TextA:MultimediaApplication⑤Fromanapplicationstandpoint,videoconferencinghasgonewaybeyondlookingatapictureofaperson;userscanlookatandupdatecharts,makedrawings,andsoon,allonline.AvideocameraandaspeakerphonearelinkedtoaPCwhichinturnislinkedtothenetwork.上一页返回TextB:ElementsofMultimedia下一页返回TextB:ElementsofMultimediaIfwebreakthewordmultimediaintoitscomponentparts,wegetmulti—meaningmorethanone,andmedia—meaningformofcommunication.Thosetypesofmediainclude:TextAudioSoundStaticGraphicsImagesAnimationFullMotionVideoLet’slookateachofthesecomponentsinmoredetail.上一页下一页返回TextB:ElementsofMultimedia1.TextWhetherornottheyhaveusedacomputer,mostpeoplearefamiliarwithtext.Textisthebasisforwordprocessingprogramsandisstillthefundamentalinformationusedinmanymultimediaprograms.Infact,manymultimediaapplicationsarebasedontheconversionofabooktoacomputerizedform.Thisconversiongivestheuserimmediateaccesstothetextandletshimorherdisplaypopupwindows,whichgivedefinitionsofcertainwords.Multimediaapplicationsalsoenabletheusertoinstantlydisplayinformationrelatedtocertaintopicthatisbeingviewed.Mostpowerfully,thecomputerizedformofabookallowstheusertolookupinformationquickly(withoutreferringtotheindexortableofcontents).上一页下一页返回TextB:ElementsofMultimediaTheWindowsoperatingenvironmentgivestheuseranalmostinfiniterangeofexpressingtext.Asamultimediaprogrammer,youcanchoosewhatfonttodisplaytextin,howbig(orsmall)itshouldbe,andwhatcoloritshouldbedisplayedin.Bydisplayingtextinmorethanoneformat,themessageamultimediaapplicationistryingtoportraycanbemademoreunderstandable.Onetypeofapplication,whichmanypeopleuseeveryday,istheWindowsHelpEngine.Thisapplicationisatextbasedinformationviewerthatmakesaccessinginformationrelatedtoacertaintopiceasy.上一页下一页返回TextB:ElementsofMultimedia2.AudioSoundTheintegrationofaudiosoundintoamultimediaapplicationcanprovidetheuserwithinformationnotpossiblethroughanyothermethodofcommunication.Sometypesofinformationcan’tbeconveyedeffectivelywithoutusingsound.Itisnearlyimpossible,forexample,toprovideanaccuratetextualdescriptionofthebeatofaheartorthesoundoftheocean.上一页下一页返回TextB:ElementsofMultimediaAudiosoundcanalsoreinforcetheuser’sunderstandingofinformationpresentedinanothertypeofmedia.Forexample,anarrationmightdescribewhatisbeingseeninananimationclip.Thiscanenhancetheunderstandingofwhattheapplicationisallaboutandleadtobettercomprehension.Expertsinlearninghavefoundthatpresentinginformationusingmorethanonesenseaidsinlaterretentionoftheinformation.Mostimportantly,itcanalsomaketheinformationmoreinterestingtotheuser.上一页下一页返回TextB:ElementsofMultimediaAudiosoundisavailableinseveraldifferentformats.Today,maybethemostcommontypeofaudioisRedbookaudiobecauseofthecolorofthecoverofthepublications,anditformsthebasisofthehighestqualitysoundavailable.上一页下一页返回TextB:ElementsofMultimediaAnotheraudiosoundformatistheWindowswavefile，whichcanbeplayedonlyonPCsrunningtheWindowsoperatingenvironment.Awavefilecontainstheactualdigitaldatausedtoplaybackthesoundaswellasaheaderthatprovidesadditionalinformationabouttheresolutionandplaybackrate.Wavefilescanstoreanytypeofsoundthatcanberecordedbyamicrophone.ThefinaltypeofaudiosoundthatmaybeusedisknownastheMusicalInstrumentDigitalInterfaceorMIDIforshort.TheMIDIformatisactuallyaspecificationinventedbymusicalinstrumentmanufacturers.Ratherthanbeingadigitizedformofthesound,theMIDIspecificationisactuallyasetofmessagesthatdescribeswhatmusicalnoteisbeingplayed.TheMIDIspecificationcan’tstoreanythingexceptintheformofmusicalnotes.MIDImusiccanbecreatedwithasequencer.上一页下一页返回TextB:ElementsofMultimedia3.StaticGraphicsImagesWhenyouimaginegraphicsimagesyouprobablythinkof“still”images—thatis,imagessuchasthoseinaphotographordrawing.Thereisnomovementinthesetypesofpictures.Staticgraphicsimagesareanimportantpartofmultimediabecausehumansarevisuallyoriented.AstheoldChineseproverbgoes,“Apictureisworthathousandwords.”Windowsisalsoavisualenvironment.ThismakesdisplayinggraphicsimageseasierthanitwouldbeinaDOSbasedenvironment.Staticgraphicsimageshaveanumberofformatsandcanbecreatedinanumberofdifferentways.Justasyoucanseeanunlimitednumberofphotographsorpictures,thetypesofstaticgraphicsimagesthatyoucanincludeinamultimediaapplicationarealmostunlimited.上一页下一页返回TextB:ElementsofMultimedia4.AnimationAnimationreferstomovinggraphicsimages，justasastaticgraphicimageisapowerfulformofcommunication,suchasthecasewithanimation.Animationisespeciallyusefulforillustratingconceptsthatinvolvemovement.Suchconceptsasplayingaguitarorhittingagolfballaredifficulttoillustrateusingasinglephotograph,orevenaseriesofphotographs,andevenmoredifficulttoexplainusingtext.Animationmakesiteasiertoportraytheseaspectsofyourmultimediaapplication.上一页下一页返回TextB:ElementsofMultimedia5.FullMotionVideoFullmotionvideo,suchastheimagesportrayedinatelevision,canaddevenmoretoamultimediaapplication.Althoughfullmotionvideomaysoundlikeanidealwaytoaddapowerfulmessagetoamultimediaapplication,itisnowherenearthequalityyouwouldexpectafterwatchingtelevision.FullmotionvideoisstillinitsbeginningstagesonPCs,anditislimitedinresolutionandsize.Evenwithadvancedmethodsofdatacompression,fullmotionvideocansuckupharddiskspacefasterthanwaterfallswhenpouringoutofabucket.

上一页下一页返回TextB:ElementsofMultimediaRightnow,therearetwomajormethodsofincorporatingfullmotionvideointoamultimediaapplication:MicrosoftVideoforWindows,andQuickTimeforWindowsfromAppleComputers.Bothproductscomewithtoolsforgettingthevideofromanexternalinput(avideocassetterecorderoravideocamera)andstoringitonyourharddiskdrive.上一页下一页返回TextB:ElementsofMultimedia6.AlloftheAboveYoucanseethatmultimediaisbynomeansjustoneoftheprecedingtechnologies.Becauseofwhathardwarecanandcannotdo,itisoftenatradeoffbetweenacertainnumberofstaticgraphicsimages,audiosound,fullmotionvideoandtext.Asyoumayguess,textualinformationtakestheleastamountofspacetostore.上一页下一页返回TextB:ElementsofMultimediaWordsandExpressionsaudio:v.音频的compression:n.压缩convey:v.搬运，传达element:n.组成元素，要素image:n.图像index:n.索引microphone:n.麦克风motion:n.运动，动作playback:n.录音重放portray:vt.描绘上一页下一页返回TextB:ElementsofMultimediaproverb:n.谚语reinforce:v.加强，补充sequencer