视频编辑外文翻译文献.docx

视频编辑外文翻译文献.docx

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视频编辑外文翻译文献

文献信息：

文献标题：

EfficientVideoEditingforMobileApplications（高效视频编辑移动应用程序）

国外作者：

IVegas，AAgrawal，TTian

文献出处：

《InternationalJournalofAdvancedComputerScienceandApplications》,2017,8

（1）:

26-30

字数统计：

英文2331单词，11235字符；中文3722汉字

外文文献：

EfficientVideoEditingforMobileApplications

AbstractRecording,storingandsharingvideocontenthasbecomeoneofthemostpopularusagesofsmartphones.Thishasresultedindemandforvideoeditingappsthattheuserscanusetoedittheirvideosbeforesharingonvarioussocialnetworks.ThisstudydescribesatechniquetocreateavideoeditingapplicationthatusestheprocessingpowerofbothGPUandCPUtoprocessvariouseditingtasks.TheresultsandsubsequentdiscussionshowsthatusingtheprocessingpowerofboththeGPUandCPUinthevideoeditingprocessmakestheapplicationmuchmoretime-efficientandresponsiveascomparedtojusttheCPU-basedprocessing.

Keywords—iOSprogramming;Imageprocessing;GPU;CPU;Objective-C;GPUImage;OpenGL

I.INTRODUCTION

Smartphoneshavebecomeanessentialpartofourday-to-daylife.Americansspendaboutonehouradayontheirsmartphonesusingmobileapplications.TheiPhoneisthemostuseddevice,occupying47%ofthesmartphonemarketshare.

Weconsumedifferenttypesofcontentonoursmartphonessuchasnews,social-media,images,videogames,music,films,TVshows,etc.Especially,thenumberofvideocontentdistributedaroundtheInternetisgrowingexponentiallyeveryyearduetopopularvideohostingplatformslikeYouTube,Facebook,SnapchatandInstagram.Theconsumptionofvideoinmobileplatformsisexpectedtogrow67%year-on-yearuntil2019ascanbeseeninFig1.

Fig.1.EvolutionofMobilevideoconsumed

AsaresultofthehighqualitycamerainiPhones,wecanrecordvideoinhighqualitywithadevicethatisalwaysinourpocket.Thevideoscanthenbesharedwithourfriendsacrossdifferentsocial-mediaplatforms.Withmoreandmorevideosbeingrecordedandshared,ithasbecomeimportantfortheuserstobeabletoeditthosevideosbeforebeingpublishedontheInternet.Videoeditingistheprocessofmanipulatingvideoimages,addingaudioand/orvisualeffects.Sincesmartphonesaregettingmoreandmorepowerfulwitheachpassingdayintermsofprocessingandmemory,itispossibletobuildiPhoneapplicationstoeditvideosthattheusersrecord,withouttheneedofacomputerandwithabetterandfasteruserexperience.

ThispaperpresentsastudyondevelopingavideoeditingapplicationforiOSplatform.TheapplicationusesimageprocessingalgorithmsandiOSprogrammingtechniques.Imageprocessingistheprocessingofimagesusingmathematicaloperationsbyusinganyformofsignalprocessingforwhichtheinputisanimage,aseriesofimages,oravideoandtheoutputmaybeeitheranimageorasetofcharacteristicsorparametersrelatedtotheimage.iOSprogrammingtechniquesuseasetoflibraries,algorithmsandbestpracticesthatareusedtobuildiPhoneapplications.

ThisapplicationallowstheusertorecordavideoortoimportavideostoredinyouriPhonecameraroll.Theusercanselectaspecificpartofthevideoandcropthevideoifitisrequired.Theusercanthenaddsomeimagefiltereffectsalongwithabackgroundsong.Finally,theusercansavetheresultedvideobacktotheiPhone.

II.METHODS

A.Technologiesused

TheapplicationisprogrammediniOSversion9.0.iOSversion9.0runsin80%oftheiOSdevicesusingxCodeversion7.3andObjective-Caslanguagedevelopment.Recently,ApplelaunchedanewprogramminglanguageforiOScalledSwift.ThisapplicationhoweverisprogrammedinObjective-CinsteadofSwiftsinceObjective-CisamoreevolvedlanguagewithmoredocumentationaboutvideoprocessingthanSwift.

B.Librariesused

FortheentireiOSapplicationflowanduserinterface,wehaveusedtheCocoaFramework,agroupofnativelibrariesprovidedbyAppletocreatetheuserinterfaceofanapplication.

Thevideocapture,videoimporting/exportingandvideocropping,isimplementedusingUIImagePickerController.ThisisaclasscreatedbyAppletoworkwithmediafiles.

ThevideofilterprocessingiscreatedusingGPUImage,athird-partylibrarycreatedbyBradLarson.ThislibrarygivesyoutheopportunitytousetheGPUtoprocessthevideoinsteadofCPU.ThevideoprocessingtoolsprovidedbyAppleonlyallowstoprocessvideousingCPU.Also,usingGPUImageyoucanusepredefinedfiltersoryoucancreatefiltersofyourown.

Topreviewthevideo,theapplicationusesCoreImage,aniOSnativelibrarythatallowsyoutoreproducemediacontentinyourapplication.

AVFoundationisusedtoaddcustombackgroundaudiotothevideos.ThisisanativeiOSlibraryprovidedbyAppletomanipulateaudioinmediafiles.

C.Views

IniOS,whenwetalkaboutaview,wearereferringtoascreenintheapp