數(shù)字媒體的教案

數(shù)字媒體的教案第1頁/共70頁2ChapterContentsSectionA:DigitalSoundSectionB:BitmapGraphicsSectionC:Vectorand3-DGraphicsSectionD:DigitalVideoSectionE:DigitalRightsManagement第2頁/共70頁FastPollTrue/FalseQuestions

AnswerAforTrueandBforFalse080100Audioisdigitizedbydividingasoundwaveintosamplesandstoringthenumbersthatrepresenttheheightofeachsample.080200Ahighersamplingrateproduceshigherqualitysoundthanlowersamplingrates.080300MP3andBMPareexamplesoftwopopulardigitalmusicformats.080400Waveisaformatforsynthesizedsound.080500Softwarewithspeechsynthesiscapabilitiescanconvertyourspokendictationintoadigitaldocument.3第3頁/共70頁FastPollTrue/FalseQuestions

AnswerAforTrueandBforFalse080600RAW,PNG,TIFF,andJPEGformatsstoregraphicsasbitmaps.080700Bitmapgraphicsareresolutiondependent.080800Whenbitmapsareenlarged,pixelinterpolationcanresultinthegraphicbecomingpixilated.080900Imagesthathavebeencompressedwithlosslesscompressioncanbereconstitutedtotheiroriginalappearancewithoutanydataloss.081000Vectorgraphicsmaintaintheirqualitybetterthanbitmapswhenresized.4第4頁/共70頁FastPollTrue/FalseQuestions

AnswerAforTrueandBforFalse081100Thetechniqueforaddinglightandshadowstoa3-Dgraphiciscalledrasterizing.081200Videoswithalowcompressionratetendtobesmall,low-qualityfiles.081300Avideowithabitrateof340willhavelesscompressionandbetterqualitythanavideowithabitrateof150.081400Recordingatelevisionshowtowatchatalatertimeisanexampleofdigitalrightsmanagement.081500Digitalwatermarks,HDCP,andbroadcastflagsrelyoncomplianthardwaredevicestoprotectcontent.5第5頁/共70頁6DigitalSoundDigitalAudioBasicsPortableAudioPlayersMIDIMusicSpeechRecognitionandSynthesis第6頁/共70頁Question082100ComputerscanworkwithdigitalaudioaswellasMIDImusic.Whichisthemoreprevalentformatandwhy?A.Digitalaudioismoreprevalentbecauseitisusedformusicdownloads.B.DigitalaudioismoreprevalentbecauseitisafarmorecompactformatthanMIDI.C.MIDIismoreprevalentbecausebrowserscanplayitwithoutaplug-in.D.MIDIismoreprevalentbecausetheAmericanswithDisabilitiesActmandatesitsuseforreadingcomputerscreens.7第7頁/共70頁8DigitalAudioBasicsSamplingasoundwave第8頁/共70頁9DigitalAudioBasicsSamplingratereferstonumberoftimespersecondthatasoundismeasured第9頁/共70頁10DigitalAudioBasicsSoundcardsareresponsiblefortransformingbitsstoredinanaudiofileintomusic,soundeffects,andnarrationsDigitalsignalprocessor第10頁/共70頁11DigitalAudioBasicsThemostpopulardigitalaudioformatsincludeAAC,AIFF,MP3,RealAudio,Wave,andWMAAudioormediaplayersoftwareallowsyoutorecordandplaydigitalaudiofilesYoucanembeddigitalaudiofilesintoaWebpage第11頁/共70頁12PortableAudioPlayersPocket-sized,battery-powereddevicethatstoresdigitalmusicZuneDigitalmusicisavailablefrom

awidevarietyofsourcesFormatsincludeAAC,MP3,WAV,

andAIFF第12頁/共70頁13MIDIMusicMIDI(MusicalInstrumentDigitalInterface)specifiesastandardwaytostoremusicdataforsynthesizers,electronicMIDIinstruments,andcomputersMIDI-capablesoundcardscontainawavetableSetofprerecordedmusicalinstrumentsoundsDoesnotproducehigh-qualityvocalsDoesnothavefullresonanceof“real”sound第13頁/共70頁14MIDIMusicMIDImusictendsnottohavethefullresonanceofdigitalaudio.第14頁/共70頁15MIDIMusicMusiccompositionsoftwareprovidestoolsforenteringnotes,specifyinginstruments,printingsheetmusic,andsavingcompositionsinformatssuchasMIDI.第15頁/共70頁16SpeechRecognition

andSynthesisSpeechsynthesisistheprocessbywhichmachinesproducesoundresemblingspokenwordsText-to-speechsoftwareSpeechrecognitionreferstotheabilityofamachinetounderstandspokenwordsSpeechrecognitionsoftware第16頁/共70頁17SpeechRecognition

andSynthesis第17頁/共70頁18BitmapGraphicsBitmapBasicsScannersandCamerasImageResolutionColorDepthandPalettesImageCompressionBitmapGraphicsFormats第18頁/共70頁Question082200BitmapfilesaretypicallyquitelargeandsoitishandytocompressthembeforeFTPingore-mailingthem.However,somebitmapfilesdon’tseemtoshrinkverymuchwhenyouuseacompressionutility,suchasWinZip.Why?A.Thefilesarealreadyassmallastheycanget.B.Compressionutilitiesuselosslesscompression,whichwon’tallowyoushrinkthesizeofafilewithoutlosingdata.C.Sometypesoffilesarealreadyincompressedformat,whichcan’tbefurthercompressed.D.Thefileshaveasmallcolorpalettethatdoesn’tallowcompression.19第19頁/共70頁20BitmapGraphicsComposedofagridofdotsColorofeachdotisstoredasabinarynumber第20頁/共70頁21ScannersandCamerasToscananimage,turnonthescannerandstartyourscannersoftware.Placetheimagefacedownonthescannerglass,andusethescannersoftwaretoinitiatethescan.ThescannedimageissavedinRAMandcanthenbesavedonyourcomputer’sharddisk.第21頁/共70頁22ScannersandCamerasThecontrolsforadigitalcameraareverysimilartothoseforananalog,orfilm,camera.Totakeaphoto,simplypointandshoot.第22頁/共70頁23ScannersandCamerasDigitalcamerasusestoragemediumSolidstatestorageTransferimagesusing:CardreadersDirectcabletransferInfraredportMediatransferDockingstationE-mail第23頁/共70頁24ScannersandCamerasGraphicssoftwareisusedtomodifyoreditbitmapgraphicsModifyindividualpixelstoRetouchphotographsWipeoutredeyeEraserabbitearsRequireabitofstorage

space第24頁/共70頁25ImageResolutionExpressedasthenumberofhorizontalandverticalpixelsHigherresolutionscontainmoredata(largerfilesize)andarehigherqualityBitmapsdonothaveafixedphysicalsize第25頁/共70頁26ImageResolutionFilesizeofbitmapscanbereducedbycroppingBitmapsareresolutiondependent第26頁/共70頁27ImageResolutionWhenyouincreasetheresolutionofabitmap,pixelinterpolationmayoccurSomeimagesmayappearpixilated第27頁/共70頁28ColorDepthandPalettesColordepthisthenumberofcolorsavailableforuseinanimageMonochromebitmapIncreasingcolordepthincreasesfilesizeTrueColorbitmap(24-bitbitmap)32-bitbitmapColorpalettesareusedtocontrolcolordepthGrayscalepaletteSystempaletteWebpalette第28頁/共70頁29ColorDepthandPalettes第29頁/共70頁30ImageCompressionAnytechniquethatrecodesdatainanimagefilesoitcontainsfewerbitsLosslesscompressionLossycompressionRun-lengthencodingFilecompressionutility第30頁/共70頁31ImageCompressionFilecompressionutilities,suchasopensource7-Zip,ziponeormorefilesintoanewcompressedfilewitha.zipextension.第31頁/共70頁BitmapGraphicFormats32第32頁/共70頁33Vectorand3-DGraphicsVectorGraphicsBasicsVector-to-BitmapConversionVectorGraphicsontheWeb3-DGraphics第33頁/共70頁Question0823002-Dvectorsdon’tlookveryrealistic,whereas

3-Dvectorstendtolookveryrealistic.Whyisthisthecase?A.3-Dimagesuseamorerealisticcolorpalettethan2-Dimages.B.3-Dimagesconstructedusingawireframecanberenderedwithsurfacetexturesandlightedwithrealisticraytracing.C.3-Dimagescanbeenlargedorshrunkmorerealisticallythan2-Dimages.D.3-Dimagescanbeanimated,whereas2-Dimagescannot.34第34頁/共70頁35VectorGraphicBasicsContaininstructionsforre-creatingapicture第35頁/共70頁36VectorGraphicBasicsVectorgraphicsresizebetterthanbitmapsVectorgraphicsusuallyrequirelessstoragespacethanbitmapsVectorgraphicsarenotusuallyasrealisticasbitmapimagesItiseasiertoeditanobjectinavectorgraphicthananobjectinabitmapgraphic第36頁/共70頁VectorGraphicBasics37第37頁/共70頁38Vector-to-BitmapConversionRasterizationsuperimposesagridoveravectorimageanddeterminesthecolorforeachpixelTracingsoftwarelocatestheedgesofobjectsinabitmapimageandconvertstheresultingshapesintovectorgraphicobjects第38頁/共70頁39VectorGraphicsontheWebSVG(ScalableVectorGraphics)andFlasharevectorgraphicformatsfortheWebFlashAnimatedGIFAdvantagesofusing

vectorgraphicsConsistentqualitySearchableCompactfilesize第39頁/共70頁403-DGraphicsStoredasasetofinstructionsContainlocationsandlengthsoflinesformingawireframeRenderingcoversawireframewithsurfacecolorandtextureRaytracingaddslightandshadowstoa3-Dimage第40頁/共70頁413-DGraphics3-Dgraphicsarebasedonawireframe,whichcanberenderedintoabitmapimagethatlooksthree-dimensional.第41頁/共70頁42DigitalVideoDigitalVideoBasicsProducingVideoFootageVideoTransferVideoEditingVideoOutputDesktop,PDA,andWebVideoDVD-Video第42頁/共70頁Question082400YouTubeispopularvideosite.WhichoneofthefollowingstatementsisNOTtrueaboutthesevideos?A.YouTubesupportsstreamingvideo.B.Youneedabrowserplug-intoviewvideosontheYouTubesite.C.YouTubevideoshavealowcompressionratioandahighbitrate.D.EachYouTubevideohasauniqueURL.43第43頁/共70頁44DigitalVideoBasicsUsesbitstostorecolorandbrightnessdataforeachvideoframeDifferentkindsofdigitalvideos:DesktopvideoWeb-basedvideoDVD-videoPDAvideo第44頁/共70頁DigitalVideoBasics45第45頁/共70頁46ProducingVideoFootageUsedigitaloranalogvideocameratoshootvideofootageDigitalvideocamerasstore

footageasaseriesofbitsAnalogvideocamerasstore

videosignalsasacontinuous

trackofmagneticpatternsVideoconferencingcameras

(Webcam)attachdirectlyto

acomputer第46頁/共70頁ProducingVideoFootage47第47頁/共70頁48VideoTransferTransfervideofootagebyconnectingacablebetweenavideosourceandcomputerVideocaptureconvertsanalogvideosignalsintodigitalformat第48頁/共70頁49VideoTransferVideocapturesoftwarecontrolsthetransferprocess第49頁/共70頁50VideoTransferRaw,uncompressedformatsareidealforeditingVideocapturesoftwarecan:DecreasevideodisplaysizeReducetheframerateCompressdata第50頁/共70頁VideoEditingLineareditingRequiresatleasttwoVCRsNonlineareditingRequiresacomputer

harddiskandvideo

editingsoftware51第51頁/共70頁VideoOutput52第52頁/共70頁VideoOutput53第53頁/共70頁54Desktop,PDA,andWebVideoDesktopvideosareusuallydisplayedonacomputerscreenSomePDAsandsmartphonescanbeconfiguredtoplaydigitalvideoWeb-basedvideosStreamingvideo第54頁/共70頁55Desktop,PDA,andWebVideoYoucanaddexternalorinternetvideostoaWebpageInternetconnectionspeedaffectsWebvideosWebvideoformatsincludeFlashVideo,MPEG4,QuickTimeMovie,WindowsMovie,andRealMedia第55頁/共70頁56DVD-VideoIncorporatedigitalvideosontoDVDswithinteractivemenusDVDauthoringsoftware第56頁/共70頁57DVD-VideoWithadvanceplanning,menusareeasytocreateOutputvideoinDVD-videoformatADVDimageisaprototypeofyourDVDStoredonyourcomputer’sharddiskThoroughlytestDVDonyourcomputerbeforeyouburnitRecordablevs.rewritableDVDs第57頁/共70頁58DigitalRightsManagementDRMBasicsSignalScramblingandDigitalWatermarksCDCopyProtectionDVDandBlu-rayDRMDRMforDigitalDownloads第58頁/共70頁Question082500Digitalrightsmanagementisanimportantaspectofprotectingdigitalmusicandmoviesfromillegaldistribution.Opponentsbelievethat:A.Digitalrightsmanagementistoohardtobreak.B.Digitalrightsmanagementhasnotbeeneffectiveforpreventinglarge-scalepiracy.C.Digitalrightmanagementformoviesiseffective,butitisnoteffectiveformusic.D.DigitalrightsmanagementshouldapplytoCDsandDVDs,butnottodownloads.59第59頁/共70頁60DRMBasicsDigitalrightsmanagement(DRM)isacollectionoftechniquesusedbycopyrightholderstolimitaccessanduseofdigitalcontentTimeshiftingPlaceshiftingFormatshifting第60頁/共70頁61SignalScrambling

andDigitalWatermarksSignalscramblingisatermcommonlyusedforobscuringcableorsatellitetelevisionimagesuntiltheyareunscrambledbyaset-topboxorotherauthorizedmechanismAdigitalwatermarkisapatternofbitsinsertedatvariousplacesinanimageoracontentstreamthatcanbeusedtotrack,identify,verify,andcontrolcontentuseBroadcastflagHDCP第61頁/共70頁62CDCopyProtectionCopyprotectionreferstotechnologiesdesignedtoprohibitconsumersfromcopyingcontent第62頁/共70頁63DVDANDBlu-rayDRMCo