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首页 MP3与无损(flac.APE)的本质区别和音质差异

MP3与无损(flac.APE)的本质区别和音质差异.doc

MP3与无损(flac.APE)的本质…

紫色草cs神
2018-04-14 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《MP3与无损(flac.APE)的本质区别和音质差异doc》,可适用于领域

MP与无损(flacAPE)的本质区别和音质差异MP与无损(flacAPE)的本质区别和音质差异TheessentialdifferencebetweenMPandflacAPEandtonequalitydifferenceEveryoneislisteningtotheformatshouldbeMPnow(accordingtothesurvey,ninetypercentoftheoilislisteningtoMP,whichincludestheuseofprofessionalplayers,mobilephones,computersandothersongsoftheengineoilWhilesevenpercentoftheoilwilllistentoOgg,AACandothersmallformatmusic,whileonlythreepercentoftheoilwilllistentoFLAC,APEetc),losslessmusicrarelylistentomusic,alargepartofthereasonisbecauseitisaportableplayeratpresentonthelosslessformatsupportistoosmall,evenifthereissuchaproductisoftenthepricenotcheap,dauntingAlotofoil,andnowdonotknowthelosslessmusic,andevenabithavenotheard(Ihavealotoffriendsarelikethis),todayIsimplypresentthemainstreammusicformatintroduceditWhenthesinger'ssongrecordedintotheoriginalfileofdigitalmusic,thenthemusicfileisverylarge,itisnoteasytostore,sopeopleputitincompression,almostallpopulardigitalmusicformatsarecompressed,likeMPaacoggflacAPE,buttheirencodingjustnotthesameway,weoftensaythatthelossless(flacAPE)thatislosslesscompression,whilethoseinfrontoftheMPsmallformatislossycompressionLosslesscompressionisliketryingtoflattenapieceofbreadThevolumeissmaller,butthequalityremainsthesameWerecordedthesound,infactmostbecausethefrequencyistoohighortoolow,isourearshearnot(someanimalsuchasbats,dogscanhearapart),sincenottohearthatwestillhavewhatSowehavetolistentothispartofthevoicedatadeletecannotsee,themusicdataisthatpartoftheleftearcanhearbecomesverysmall,easytostore,thiscompressionmethodcalledlossycompression(suchasMP)Sowhat'sthedifferencebetweenlosslessandlossysoundqualityHaveyouhadanyexperiencelikethat,thesamesong,thenextMPandaFLAC,andthenputonheadphones,butwecan'tfindthedifferenceinsoundqualityatall!ButifyoulistentotheMPalldaylongandlistentothewholedaywithoutdamagingit,itwillbedifferent!It'seasytogettiredoflisteningtoMPearsalldaylong,butit'snoproblemhearingit(aslongasyoudon'tfallasleep)!WhatisthecauseofthisThat'swhatIsaidtodayaboutthedifferencebetweenlosslessandlossysoundquality!Weknowthatmusicisrhythm,rhythmandrhythmaredifferent,suchasthetrebleandbassbetweenboththesongandhowquicklyorslowly,itwillhaveanexcessive,losslessmusicfeatureisbothinrhythmwithnosound(whetherwecanhearit),thedataisalwaysthesteadyflow,letyourheadsetinmagneticfaststablevibration,soundnaturalandtrueandMPlossyformatbecauseofroundingthehumaneartohearsomeofthedata,soyouinthemagneticblockvibrationheadsetisnotnatural,resultinginasoundvibration,whennosoundisshakingthismagnetwillproduceexcessivevibrationisnotsmooth,burrmurmur,maybeyoucan'thear,butsuchalongtimelisteningearwilluncomfortableit(ofcourse,Somegoodheadphonescanavoidthisglitch,butmostofthemwon'tbeabletoaffordthem!Oftenpeoplelaughatthemusicfans,noticethatthesongsareinnocentandthefeverisreasonable!Hethatlistenstotheeardoesnotnecessarilyhaveafever,buthewhohasafeverwillsurelyhearnothing!wavaudioformatofthethreemajorparameters,andtheparametersforthemeaningofaudiofilesThewavfilehasparameters:samplingfrequency,channelnumber,quantizationbitnumber,andrateofThebestoftheseparametersisthesoundtracknumber,sodon'tintroducethisparameterThentheparametersIwillintroducearesamplingfrequencyF,quantizationbitB,andrateRsamplingfrequencyInthethreeparametersinsidethemostimportantisthesamplingfrequency,behindthetwoparametersarebasedonthetransmissionandstorageprocessaccordingtotherequirementsandget,butitisthesamplingfrequency,signaltheanalogworldtothedigitalworldbridgeBeforetalkingaboutthesamplingfrequency,wecanfirstrecallthesituationwhenwestudiedparabolainjuniorhighschoolInjuniorhighschool,whentheteachertaughtustodrawparabola,whatmethodwasusedtodrawIfyouthinkback,youshouldremember,it'sthepointmethodYes,theparabolacanbedrawnwithpointsWhatisanaudiosignalisactuallycosinewave,butthefrequencyandamplitudeofthisYuXianboarevariableovertimeWewanttorecordthisaudiosignal,itisimpossibletorecordthevalueofeachmoment,butwecanrefertotheparabolamethodtodescribetheaudiosignalexactlyaslittleaspossibleAndsamplingfrequency,itisdoingthiswork,thatis,inasecondwewanttorecordthenumberofaudiosignals,howmanypointscanbeapproximatelyaccurateexpressionofthisaudiosignalInsignalprocessing,thereissuchatheoremcalledNyquist'stheoremHowdoyougetthistheoremYoudon'tneedtoknowThisisasignalprocessingprofessionalYouneedtoknow,likemeUndefinedWeneedtoknowisthatthistheoremtellsusthatifwewanttoaccuratelyrecordasignal,thesamplingfrequencyoftwotimes,wemustbegreaterthanthemaximumfrequencyisequaltotheaudiosignalthatisthemaximumfrequencythatisF>=*fmaxInthewavformat,F=kHzWeknowthatthefrequencyrangeofthehumaneariskHz,thatistosay,ifwewanttoaccuratelyrecordthisaudiosignal,thesamplingfrequencyisthelowest,atleastkHzAsforwhykHz,nototherfrequencies,I'msorry,Idon'tknowUndefinedBut,atleastwecanbesurethatthekHzsamplingfrequencycanrecordexactlylessthankHzoftheaudiosignal,thisisenoughQuantizationBitsAlthoughwehavethesamplingfrequency,wecanrecordtheaudiosignalsaccuratelyHowever,therecordedaudiosignalsareanalogandcannotbeprocessedbythecomputerHerewearegoingtocomeupwithanewconcept,analoganddigitalThereisadifferencebetweenanaloganddigitalLetmegiveyouabriefintroductionForexample,thisrangeAlinesegment,wecanarbitrarilytakeapoint,thevalueofthispointcanbedetermined,thepointoftherangeofvaluescanbedetermined,butthepointofthenumberofvaluescannotbedetermined,andthisistheanalogAcomputerthatcannotdeterminethenumberofpossiblevaluescannotbeprocessedbyacomputerThequantityisthesameastherest,andthethirdisnotthesameThenumberofvaluescanbedetermined,sothatthecomputercanhandleitthisrange,dependingontheaccuracyrequirements,wecandeterminethenumberofvaluesrequiredAndthequantizationbit,whichisdoingthisjob,determinestherecordingpointoftheaudiosignalandthepossiblenumberofitsvaluesWeknowthatthequantizationbitwavofBis,andthisisadigitnumberHetellsusthatthenumberofpointsatwhicharecordpointcanbeis,orsplitittimes,andIthinktheprecisionisenoughUndefinedRateNow,thesamplingfrequencyandquantizationaccuracyaretold,theturnofthecoderate,firstdrinksalivafirstUndefinedHowdoyougettherateVerysimple,thatis,samplingfrequency,Xquantizationbit,Xchannelnumber,thatis,R=F*B*R=kHz*b*=kbps~=kbpsThisistherate,althoughtherateiscalculated,buthehasanexactmeaning,thatis,itcanstoretheamountofinformationinasecond,rememberthattheamountofinformationHere,youmightberemindedthatMP,kbps,AAC,Kbps,losslesscompressionformatkbpsThensomepeoplewonder,isnotit,thegreatertherate,thebetterForlossyformats,thenthegreaterthebitrate,thebetterHowever,thereisapremisethattheconvertedsongmustbealosslessformatthatisburnedfromthegenuineCD,andthetransformationisthesamelossyformat,suchasMPOtherwise,youconvertakbsMPsongintoakbpsbitrateMP,andthesoundqualitywillnotimproveForlosslesscompressionformats,thesizeofthecoderateswillbemeaninglessThesizeofthebitratetellsyoujusthowwellhiscompressionalgorithmisgoodenoughButIhavetoremindyouthatthisbitofcoderateisjustlikethisHecan'ttellyouthatthesavedinformationisgoodorbadHecanonlytellyouthathehassavedsomuchinformationYes,he'sactuallyawarehouseHedoesn'tcarewhatheputsinthewarehouseHejustkeepsitfullUndefinedWell,here,thethreeparametersofthewavformatarefinished,theremaybealotofpeoplewonderingwhyItalkaboutthisantiquewavformat,notMPahAACtheselossyformat,orFLAC,apelosslesscompressionformatThereasonissimple,becausewavisthenearestanalogdigitalquantity,themostprimitivedata,andthelatterformatisbasedonWAV,accordingtotheirowncharacteristicstodealwithitWhat'smore,thethreeparametersmentionedabovearestillusedinthelaterformatNaturally,firstintroduceWAV,undefinedcompressionprincipleinlossyformatInthissection,aswellasthefollowinglosslessformatcompressionprinciple,Similarly,asecondaudio,afterlossycompression,theratevalueofkbp,thenthesizeisonlyKB!!!forwavformat!!!Useaslittledataaspossibletostoreasmuchusefulinformationaspossible,anddosoinalossyformat!!!That'swhytheformatissopopularUndefinedcompressionprincipleoflosslesscompressionformatWiththedevelopmentofstoragetechnology,theamountofinformationwecanstorebecomesmoreandmorebig,andthestorageofwavformatbecomesnothinginterestingSincethereisnopear,whyshouldtheintroductionoflosslesscompressionformatThereasonissimple,sinceIMBcanstorelosslesscompressionformats,whydoIstillstorewavformatsSolosslesscompressionformatshavedevelopedLosslesscompressionformatsandlossyformatshaveonethingincommon,thatis,compressionThedifferenceis,losslessThen,howcanwedolosslesscompressionWecanrefertosecondmethodsoflossycompressionForexample,thesamerecordpoints,,,,,,ifwewantlosslesscompression,weonlyneedtorecord(),(),and()Inthisway,weonlyneedthreerecordpointstorecord,soweneedrecordpoints,anditiscompressedaswellWhat'smore,losslesscompressionThat'sonewayofthinking,buthetellsusthatlosslesscompressionispossibleforinformationprocessingTorecordanaudiocomplete,donotneedtogotoWAVformat,losslesscompressionwilldoSimilarly,therateofthisparametertocompare,asecondaudio,afterlosslesscompression,theratevalueofkbps,thesizeofMBIt'sabouthalfofwavLargecapacityplayersupportlosslesscompressionformat,smallcapacityplayerisfun,lossyformat,eachhasitsownlocation,technologydevelopmentisindeedagoodthing,undefinedWhenIseesomeoneaskingwhetherWAV,FLACandapemakeanydifference,I'llmakeasummaryhereAftertheintroductionoftheabovealgorithmprinciple,wecanseethat,ifonlyfromthefileitself,WAVandallotherlosslesscompressionformatsarenotdifferentfromthesavedinformationInforums,peopleoftenseethetwoquestionsrelatedtolosslessformat:losslesscompression,whetherthereisanydifferencebetweentheformatandlosslesscompressionformat,andwhetherthereisanydifferencebetweenwavandlosslesscompressionformatsThefirstquestion,Icananswernow,yesButthedifferenceisnotinthewholecourseoftheinformationrecording,butinthedifferencebetweenthecompressionalgorithmandtheformatadoptedbythealgorithmThat'swhythesamesong,apeformatissmallerthanFLAC,becausethealgorithmisdifferentAsfortheacoustics,theperformancewillcomewithsecondquestions,inthefifthpartFrequencyspectrumanalysisofaudiofilesThissectionanalyzesdifferentaudioformatsanddifferentbitratesinthesameaudioformatProvideareferenceforthosewhoworryaboutwhichaudioformattochooseTheaudioformatstobeanalyzedareMP,AAC,threeformats,losslessformatasreferenceformatSinceI'musingFBconversion,theMPformatonlyhastheVBRmodeandthehighestcbrSo,MaybefamiliarwiththecoderateisdifferentHowever,Iusedparenthesestoindicatethecorrespondingbitratevalue,whichisaprobablevalue,notnecessarily,butitcanbereferredtoTheMPbitratesareVBR,V(~kbps),V(~kbps),V(~kbps),andCBR'skbpsInordertocorrespondtotheVBRschemaofMP,AACusestheVBRpatternaswellTheAACbitratesareQ(kbps),q(kbps),q(kbps),Q(kbps),Q(bps)Thereasonforthischoiceisthatpeopleareaccustomedtotheratevaluesofkbps,kbps,KbpsandkbpsWhenselectingtheconversionmodeofMP,thereferencerateisascloseaspossibletothecustomaryratevaluesBecauseAACismuchbetterthanMPincoding,theAACconversionmodeistheconvertedfilesizeasclosetotheMPsizeaspossibleAsfortheQmodel,itisincontrasttolosslesscompressionformatsFirst,comparetheformatofeachaudiofilewiththecorrespondingbitrateattachattachPriortothedescription,theaudiofileinterceptionisEason'stenyears(ss)thissection,usingtheonlinedownloadlossless,interceptionsoftwareusinggoldwaveFirst,avolumetricanalysisObviously,thesmallestvolumehereisVMP(kbps),correspondingtotheqaac(kbps)ThesecondgradeisVMP(~kbps),correspondingtoqaac(kbps)ThethirdgradeisVMP(kbps),correspondingtoqaac(kbps)ThefourthgradeiscbrMP(kbps)andthecorrespondingqaac(kbps)Finally,qaac(kbps)andthecorrespondingflacIftheoriginaldiskisgenuine,itscorrespondingqualityislower,junior,intermediate,advanced,andhighestFirstonthehighestlevelofspectrogramNondestructivespectrogramQaacspectrogramLetmeexplainfirst,theabscissaistime,theordinateisthefrequency,thewhitenessofthepointistheintensityofsoundcorrespondingtothetimeandfrequencySocallspectrumBycontrast,wefindthatthefrequencyreproductionrangeoftheqaacinthesoundisnotdifferentfromthelossless,andthedrytokHzwithoutpressureHowever,thefrequencyreproductionstrengthofthesoundisdefective,andthefrequencyandsoundintensityareabsentinsometimeperiodsPicturedaboveQaacdefectTheredcircleispartofthemissingpartAsyoucansee,qaacstillfailstorecordperfectlyindetail(afterall,itisharmful),but,asawhole,theinformationitretainsisveryclosetolosslessPersonally,asahighfidelityformat,thehighbitrateAACisqualifiedThenthespectrogramcomparisonchartofhighgradeQaacMPBycomparison,wecanfindthatthespectrumofMPishigherthankHzacrosstheboard,thefrequenciesareremoved,whiletheqaacisdrytokhzpear,indetail,thetwoaresimilar,Iamnotonthemap,so,thisroundofAACwonIntermediategradespectrumcomparisonchartQaacVmpTotheintermediatelevel,theMPformatreacheskHzinspectralreproduction,whileAACiskHzIntermsofsounddetail,thetwoarebasicallysimilar,thisroundisMPformatwinsTheprimarygradesofspectrogramQaacVmpAttheprimarylevel,thefrequencyoftheMPformataveragesatkHz,andmanycangouptokHz,whiletheAACformatisthesameHowever,intermsofdetailpresentation,AAC'svoiceoverkHzismuchmorethanMP'sAndbelowthekHzpart,thetwoareprettymuchthesameSo,thisround,AACwinsLowgradeQaacVmpInthelowerlevel,MPisonesizefitsalltokHz,andAACisanaveragekHz,manycapabletokHzBelowthekHzpart,theAACrecordisnotMPcompletePersonallyfeelthatthisboutofplayandThroughthiscomparison,wecanfindthedifferencebetweentheconceptofMPandAACinlossycompression,andMPasfaraspossibleinthefrequencyrangethathecanrecordWhileAACissacrificingthelowfrequencypartofthedetailsinexchangeforhighfrequencyreservations,atlowbitrates,whoisgood,whodoesnotlookgood,personalchoiceAthighbitrates,AACisclearlysuperiortoMP,andAACcanretainasmuchaspossibleinthelowfrequencypartorthehighfrequencypart,whiletheMPisstillpowerlessinthehighfrequencypartpersonalrecommendationsforaudioformatselectionInthethirdpart,I'veraisedtwoquestionsaboutthequalitydifferencebetweenlosslesscompressionformatsandthedifferencebetweenwavandlosslesscompressionformats,whereI'llanswerInthefourthpart,weunderstandtheadvantagesanddisadvantagesoflossyaudioformatsthroughthespectrogramcomparison,thelossyformatselectionasthegroundworkHowever,beforeIanswerthethirdpartandrecommendtheformat,I'dliketointroducetheflowchartoftheaudiowhenitisbeingplayedWAVformat:wavdatastream"DAC"filtercircuit"amplificationcircuit"outputLossyformat:lossydatastreamdecoding"DAC"filtercircuit"amplificationcircuit"outputLosslesscompressionformat:losslesscompression,datastreamdecompressionDACfiltercircuitamplificationcircuitoutputExplanation:thefunctionofDACistochangedigitalsignalsintoanalogsignalsThefiltercircuitistoremovetheunwantedfrequencycomponentsandamplifythecircuitThisistoenlargetheanalogsignalssothattheycanbeoutputeasilyThroughtheplaybackflowchart,wecanseethatwavformatplaybackisthesimplest,whilelossyformatsandlosslesscompressionformatsareonestepmoreInthesignalprocessing,thereissuchasentence"erroriseverywhere""Theimplicationofthissentenceisthatthegreatertheprobabilityoferrorgenerationandthegreatertheaccumulationoferrors,ineachstepoftheprocessForlossyformats,theonlyadvantageofalosslessformatinformatisthatthecompressionratioislargeenough,andthiscompressionrateisbasedonsacrificingsoundquality,andthesoundqualityisnotaslosslessasnormal"Arethereanydifferencesbetween"ape"and"FLAC","Wavisbetterthanlosslesscompressionformats,"InowansweronebyoneBeforeyouanswer,wecomparethelosslesscompressionformatwiththewavplaybackprocess,andyoucanseethatthelosslesscompressionformathasonemore"decompression"stepthanwavFordifferentlosslesscompressionformats,thealgorithmsfordecompressionaredifferentThosewhosaythatwavisbetterthanlosslesscompressionformatmaketheirviewsreasonableWhywouldIsaythatNo,losslesscompression,sinceit'slossless,thereshouldbenodifferenceYes,intermsoftheinformationintegrityofthedocument,yes,WAVandotherlosslesscompressionformatsdonotmakeanydifference!!!Thedifferenceisnotinthefileitself,butintheplaybackprocess!!!Becausethelosslesscompressionformatisonestepmorethanthewavformatintheplaybackprocess!!!That'sdecompression!!!!SupposewecanguaranteethatthefollowingDAC,filtercircuits,andamplifiercircuitsarethesameHowever,moreunderstandingofthisstepofcompressionmayhaveanimpactonthequalityofsoundWhydoIsaythisDecompressionmayaffectsoundqualityIdon'tknowtheprincipleofinfluence,buttheerroriseverywhere,aswehavesaidbeforeThismeansthattheerrorgeneratedbythisstepmayaffecttheoverallqualityofthesoundAstowhetherthisinfluencecanbeignored,itdependsonthemanufacturer'sskillSimilarly,thelosslesscompressionformatsdonotlookatthefinaldifferenceinquality,noristheformatitself,butwhetherthe"decompression"isgoodenoughtoignoretheimpactoftheerrorWiththeabovebroadcastflowisintroduced,andthefourthpartofthespectrumanalysis,wecanaccordingtotheuseoftheenvironment,theformatrecommendedRegardlessofthesizeofaudiofiles,thepreferredchoiceforqualityisofcourselosslessformatIfyourfrontendcansupportlosslesscompressionformats,andyourplaybacksystemcanrecognizethedifferencebetweenwavandlosslesscompressionformats(thatis,youcanheartheerrorofthedecompression,wav)Otherwise,onlosslesscompressionformatConcernedaboutthesizeofaudiofiles,butalsothepursuitofsoundquality,thehighbitrateaacHowever,hereisapremise,youplaysystemtobeabletolistentothehighrateofAACandMPdifference,otherwise,orobedientlyontheMP,donottossaboutIfyoudon'tcareaboutthesoundquality,justgowiththeMPThere'sabigpremisehereTheseaudiofilesarereallylossless,notfakeOtherwise,foralargewarehouse,thecontentsarestillgarbage

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