視頻剪輯外文翻譯—高效視頻編輯移動(dòng)應(yīng)用程序

1、<p>　　字?jǐn)?shù)：英文2331單詞，11235字符；中文3722漢字</p><p>　　出處：I Vegas,A Agrawal,T Tian.Efficient Video Editing for Mobile Applications[J]International Journal of Advanced Computer Science and Applications.2017,8(1):26

2、-30</p><p><b>　　外文文獻(xiàn)：　</b></p><p>　　Efficient Video Editing for Mobile Applications</p><p>　　Abstract Recording, storing and sharing video content has become one of the

3、 most popular usages of smartphones. This has resulted in demand for video editing apps that the users can use to edit their videos before sharing on various social networks. This study describes a technique to create a

4、video editing application that uses the processing power of both GPU and CPU to process various editing tasks. The results and subsequent discussion shows that using the processing power of both the GPU a</p><

5、p>　　Keywords—iOS programming; Image processing; GPU; CPU; Objective-C; GPUImage; OpenGL</p><p>　　I.INTRODUCTION</p><p>　　Smartphones have become an essential part of our day-to- day life. Ame

6、ricans spend about one hour a day on their smartphones using mobile applications. The iPhone is the most used device, occupying 47% of the smartphone market share.</p><p>　　We consume different types of cont

7、ent on our smartphones such as news, social-media, images, video games, music, films, TV shows, etc. Especially, the number of video content distributed around the Internet is growing exponentially every year due to popu

8、lar video hosting platforms like YouTube, Facebook, Snapchat and Instagram. The consumption of video in mobile platforms is expected to grow 67% year-on-year until 2019 as can be seen in Fig 1.</p><p>　　Fig.

9、 1. Evolution of Mobile video consumed</p><p>　　As a result of the high quality camera in iPhones, we can record video in high quality with a device that is always in our pocket. The videos can then be share

10、d with our friends across different social-media platforms. With more and more videos being recorded and shared, it has become important for the users to be able to edit those videos before being published on the Interne

11、t. Video editing is the process of manipulating video images, adding audio and/ or visual effects. Since smartphones are </p><p>　　This paper presents a study on developing a video editing application for iO

12、S platform. The application uses image processing algorithms and iOS programming techniques. Image processing is the processing of images using mathematical operations by using any form of signal processing for which the

13、 input is an image, a series of images, or a video and the output may be either an image or a set of characteristics or parameters related to the image. iOS programming techniques use a set of libraries, </p><

14、p>　　This application allows the user to record a video or to import a video stored in your iPhone camera roll. The user can select a specific part of the video and crop the video if it is required. The user can then a

15、dd some image filter effects along with a background song. Finally, the user can save the resulted video back to the iPhone.</p><p>　　II.METHODS</p><p>　　A.Technologies used</p><p>

16、　　The application is programmed in iOS version 9.0. iOS version 9.0 runs in 80% of the iOS devices using xCode version 7.3 and Objective-C as language development. Recently, Apple launched a new programming language for

17、iOS called Swift. This application however is programmed in Objective-C instead of Swift since Objective-C is a more evolved language with more documentation about video processing than Swift.</p><p>　　B.Lib

18、raries used</p><p>　　For the entire iOS application flow and user interface, we have used the Cocoa Framework, a group of native libraries provided by Apple to create the user interface of an application.<

19、;/p><p>　　The video capture, video importing/exporting and video cropping, is implemented using UIImagePickerController. This is a class created by Apple to work with media files.</p><p>　　The vide

20、o filter processing is created using GPUImage, a third-party library created by Brad Larson. This library gives you the opportunity to use the GPU to process the video instead of CPU. The video processing tools provided

21、by Apple only allows to process video using CPU. Also, using GPUImage you can use predefined filters or you can create filters of your own.</p><p>　　To preview the video, the application uses Core Image, an

22、iOS native library that allows you to reproduce media content in your application.</p><p>　　AVFoundation is used to add custom background audio to the videos. This is a native iOS library provided by Apple t

23、o manipulate audio in media files.</p><p><b>　　C.Views</b></p><p>　　In iOS, when we talk about a view, we are referring to a screen in the application. Our application has four diffe

24、rent views, as discussed below.</p><p>　　The first view allows the user to select a video for editing. The user can select between recording a video using the iphone camera and importing a video from the iPh

25、one camera roll. The user can also select certain parts of the video to be processed, and delete the rest of the video. The new video segment, thus created, is saved in a temporary directory inside the application.</p

26、><p>　　Once the video is selected for editing, the filter screen appears. This view provides a preview of the video where the user can select a filter to apply. There is an option to keep the video as it is wit

27、hout applying any filters. When a filter is selected, the application sends the video to the GPU. This means that the CPU is not processing the video, as the GPU works as a separate thread. While the video is being proce

28、ssed, a loading icon is displayed. When the process is complete, the processe</p><p>　　The third view is the audio view. This view shows a classical iOS TableView with a list of all the available songs that

29、can be chosen for the video. The song files are stored with the application, as the application only offers a few songs and the durations are not longer than twenty seconds. When the user selects a song, the video is pro

30、cessed again. The processing uses the CPU by creating a parallel thread, so now the application continues to run in the main thread. The user also has the optio</p><p>　　The fourth view offers a final previe

31、w of the video with the new audio included. Here, the user has the option to save the video to the camera roll. Note that, so far, the video is only stored in a temporary folder. This is being done to prevent unnecessary

32、 use of memory space and CPU as it is more efficient to work with a file stored in a temporary directory inside the application space.</p><p><b>　　D.Filters</b></p><p>　　GPUImage wor

33、ks on top of OpenGL shaders. OpenGL Shaders are programs designed to run on some stage of a graphic processor (GPU). As a result, our application can process videos using GPU and also use predefined image filters or crea

34、te a custom filter using OpenGL features.</p><p>　　As mentioned earlier, when the application starts processing the video, the CPU creates a parallel thread. This parallel thread is then processed by the GPU

35、 as shown in Fig.2.The GPU reads every frame of the video and processes each frame separately. When all the frames are processed, the GPU returns the control back to the CPU.</p><p>　　Fig. 2. GPU and CPU sta

36、te while processing a video</p><p>　　The process that OpenGL Shaders use to process an image is called rendering pipeline. The OpenGL rendering pipeline defines a number of stages for this shaders as shown i

37、n Fig. 3.</p><p>　　Fig. 3. States of the rendering pipeline</p><p>　　The vertex shader transforms the video images into individual vertices. Primitive assembly connects the vertices created by t

38、he vertex shader to form figures which are called primitive units. Rasterization is then applied, which transforms the primitive units into smaller units called fragments. In the fragment processing stage, colors and tex

39、tures are applied to the fragments, which is then saved in a Frame Buffer. The frame buffer allows us to create an image or show the image on a screen. The</p><p>　　III.RESULTS</p><p>　　Fig. 4 d

40、isplays the first view of the application. In this view, you can select two options; Record a video using the iPhone camera or import a video from the camera roll. Fig. 5 shows the view where the user can crop the video.

41、 Fig. 6 shows the view where a filter can be applied to the video. The application currently provides 15 popular filters, as shown in Table I.</p><p>　　Fig. 4. First app view with two available options</p

42、><p>　　Fig. 5. Second app view to crop the video</p><p>　　Fig. 6. Third app view to apply filters</p><p>　　TABLE I.FILTERS AVAILABLE</p><p>　　Fig. 7 provides a view where

43、 the user can choose an audio song that will be added to the video. Currently, the application provides 10 audio songs. These songs have been downloaded from jammendo.com, which are under Creative Commons license. The la

44、st view, as shown in Fig. 8, provides a preview of the processed video and gives user the option to save the video on the camera roll.</p><p>　　Fig. 7. Fourth app view to select an audio song</p><

45、p>　　Fig. 8. Fifth app view to save the edited video</p><p>　　IV.DISCUSSION</p><p>　　A.Using GPU or CPU for image processing</p><p>　　In the methods section, we mentioned about us

46、ing GPU processing alongside the CPU processing for many of the processing tasks. For parallel operations like video processing, using GPU has significant performance advantages over CPU. The GPUImage framework takes onl

47、y 2.5 ms on an iPhone 4 to upload a frame from the camera, apply a gamma filter, and display, versus 106 ms for the same operation using Core Image and 460 ms using CPU-based processing. This makes GPUImage 40X faster th

48、an Core Image a</p><p>　　CoreImage is the library provided by Apple to process images and video files. In newer devices like the iPhone 6, we can achieve the same performance using CPU or GPU. However, for t

49、his study we decided to use GPU processing because older devices like the iPhone 4 and iPhone 5 are more responsive when we utilize both GPU and CPU for video editing tasks.</p><p>　　B.Duration of the videos

50、</p><p>　　Several social networks such as Instagram and Snapchat limit the length of videos that can be uploaded to 10 or 15 seconds. When a user uses a mobile application, they want a fast, responsive and a

51、 seamless user experience, and processing a video longer than 20 seconds can take a longer time thus negatively impacting the user experience. So, we decided to limit the duration of the videos that the users can take us

52、ing the application to 20 seconds. Table II shows the video processing time using t</p><p>　　TABLE II. 1080P VIDEO PROCESSING TIME ON AN IPHONE 6</p><p>　　Table III shows the video processing ti

53、me using the application for videos of different durations in 640p (unlike videos in Table II that are in 1080p). </p><p>　　TABLE III. 640P VIDEO PROCESSING TIME ON AN IPHONE 6</p><p>　　Table IV

54、 shows the video processing to apply blur effect using the application on iPhone 5s. All videos are in 1080p with 30 frames per second. As the data shows, the processing time required by an iPhone 5s is almost the double

55、 of the time required by iPhone 6 as shown in Table II. This is as a result of the iPhone 5s GPU being half as powerful as the iPhone 6 GPU.</p><p>　　TABLE IV. 1080P VIDEO PROCESSING TIME ON AN IPHONE 5S<

56、/p><p>　　C.Future Work</p><p>　　Future work will involve improving the scalability of the application. For instance, we will have the songs list stored on the server. The application will be able t

57、o connect to the server and the songs can be downloaded to the smartphone. Another new feature will involve adding the option to select between different image qualities for the output video. With lower quality export vi

58、deos, the processing will be faster as compared to a video generated using the high quality option.</p><p>　　V.CONCLUSION</p><p>　　Mobile applications and video content have become an integral p

59、art of our lives. It has become common for people to use their mobile phones to record, edit and share videos on social networking sites. This paper presents a video editing application for iOS devices that can be used t

60、o record videos and edit them. The edit features include cropping, applying filters or adding background audio. The application describes a technique to use the processing power of both the GPU and the CPU to improve <

61、;/p><p><b>　　中文譯文：</b></p><p>　　高效視頻編輯移動(dòng)應(yīng)用程序</p><p>　　摘要 錄制、存儲(chǔ)和共享視頻內(nèi)容已成為智能手機(jī)最受歡迎的應(yīng)用之一。這導(dǎo)致了對(duì)視頻編輯應(yīng)用程序的需求，用戶可以使用它來(lái)編輯視頻，然后再發(fā)布到社交網(wǎng)絡(luò)上。本研究介紹了一種創(chuàng)建視頻編輯應(yīng)用程序的技術(shù)，該應(yīng)用程序使用GPU和CPU的處理能力來(lái)處

62、理各種編輯任務(wù)。結(jié)果和后續(xù)討論表明，與僅基于CPU的處理相比，在視頻編輯過程中使用GPU和CPU的處理能力會(huì)使得應(yīng)用程序的時(shí)間效率和響應(yīng)速度更快。</p><p>　　關(guān)鍵詞——iOS編程；圖像處理；GPU；CPU；Objective-C；GPUImage；OpenGL</p><p><b>　　1.簡(jiǎn)介</b></p><p>　　智能手機(jī)

63、已成為我們?nèi)粘Ｉ畹闹匾M成部分。美國(guó)人每天大約花一個(gè)小時(shí)在他們的智能手機(jī)上使用移動(dòng)應(yīng)用程序。iPhone是最常用的設(shè)備，占智能手機(jī)市場(chǎng)份額的47％。</p><p>　　我們?cè)谥悄苁謾C(jī)上使用不同類型的內(nèi)容，如新聞、社交媒體、圖像、視頻游戲、音樂、電影、電視節(jié)目等。特別是，由于受歡迎的視頻托管平臺(tái)，如YouTube、Facebook、Snapchat和Instagram，互聯(lián)網(wǎng)上發(fā)布的視頻內(nèi)容數(shù)量每年都在成倍增長(zhǎng)

64、。預(yù)計(jì)到2019年，移動(dòng)平臺(tái)的視頻消費(fèi)量將同比增長(zhǎng)67％，如圖1所示。</p><p>　　圖1.移動(dòng)視頻消費(fèi)的發(fā)展</p><p>　　iPhone具有高品質(zhì)的攝像頭，我們可以用其設(shè)備錄制高質(zhì)量的視頻。這些視頻可以通過不同的社交媒體平臺(tái)與我們的朋友分享。隨著越來(lái)越多的視頻被錄制和共享，用戶在發(fā)布互聯(lián)網(wǎng)之前就能夠編輯這些視頻變得非常重要。視頻編輯是處理視頻圖像、添加音頻和/或視覺效果的過程

65、。由于智能手機(jī)在處理和內(nèi)存方面越來(lái)越強(qiáng)大，因此可以構(gòu)建iPhone應(yīng)用程序來(lái)編輯用戶錄制的視頻，而無(wú)需計(jì)算機(jī)，并且具有更好更快的用戶體驗(yàn)。</p><p>　　本文介紹了一個(gè)開發(fā)iOS平臺(tái)視頻編輯應(yīng)用程序的研究。該應(yīng)用程序使用圖像處理算法和iOS編程技術(shù)。圖像處理是使用數(shù)學(xué)運(yùn)算處理圖像的過程，它使用任何形式的信號(hào)處理，其中輸入是圖像、一系列圖像或視頻，輸出可以是圖像或與圖像相關(guān)的一組特征或參數(shù)。iOS編程技術(shù)使用

66、了一組用于構(gòu)建iPhone應(yīng)用程序的庫(kù)、算法和最佳實(shí)踐。</p><p>　　此應(yīng)用程序允許用戶錄制視頻或?qū)氪鎯?chǔ)在iPhone相機(jī)相冊(cè)中的視頻。用戶可以選擇視頻的特定部分，并在需要時(shí)裁剪視頻。用戶可以添加一些圖像濾鏡效果以及背景歌曲。最后，用戶可以將結(jié)果視頻保存回iPhone。</p><p><b>　　2.方法</b></p><p>&

67、lt;b>　　A.技術(shù)應(yīng)用</b></p><p>　　該應(yīng)用程序在iOS版本9.0中進(jìn)行編程。iOS版本9.0運(yùn)行在80%的iOS設(shè)備中，使用xCode7.3和Objective-C作為語(yǔ)言開發(fā)。最近，Apple推出了一款名為Swift的iOS新編程語(yǔ)言。然而，這個(gè)應(yīng)用程序是在Objective-C中編寫的，而不是Swift，因?yàn)镺bjective-C是一種更進(jìn)化的語(yǔ)言，其中有關(guān)于視頻處理的文

68、檔比Swift更多。</p><p><b>　　B.庫(kù)應(yīng)用</b></p><p>　　對(duì)于整個(gè)iOS應(yīng)用程序流和用戶界面，我們使用了Cocoa Framework，這是Apple提供的一組本機(jī)庫(kù)，用于創(chuàng)建應(yīng)用程序的用戶界面。</p><p>　　視頻采集、視頻導(dǎo)入/導(dǎo)出和視頻裁剪使用UIImagePickerController來(lái)實(shí)現(xiàn)。這是

69、Apple創(chuàng)建的用于處理媒體文件的一個(gè)分類。</p><p>　　視頻濾鏡處理是使用由BradLarson創(chuàng)建的第三方庫(kù)GPUImage來(lái)實(shí)現(xiàn)的。該庫(kù)使用戶有機(jī)會(huì)使用GPU來(lái)處理視頻而不是CPU。Apple提供的視頻處理工具只允許使用CPU處理視頻。另外，使用GPUImage可以使用預(yù)定義的濾鏡，也可以創(chuàng)建自己的濾鏡。</p><p>　　要預(yù)覽視頻，應(yīng)用程序使用了Core Image，這

70、是一個(gè)iOS本機(jī)庫(kù)，允許用戶在應(yīng)用程序中重現(xiàn)媒體內(nèi)容。</p><p>　　AVFoundation用于為視頻添加自定義背景音頻。這是Apple提供的的本機(jī)iOS庫(kù)，用于處理媒體文件中的音頻。</p><p><b>　　C.視圖</b></p><p>　　在iOS中，當(dāng)我們談?wù)撘粋€(gè)視圖時(shí)，我們指的是應(yīng)用程序中的一個(gè)屏幕。我們的應(yīng)用程序有四種

71、不同的視圖，如下所述。</p><p>　　第一個(gè)視圖允許用戶選擇一個(gè)視頻進(jìn)行編輯。用戶可以選擇使用iPhone相機(jī)錄制視頻和從iPhone相機(jī)相冊(cè)導(dǎo)入視頻。用戶還可以選擇要處理的視頻的某些部分，并刪除視頻的其余部分。新創(chuàng)建的視頻片段保存在應(yīng)用程序內(nèi)的臨時(shí)目錄中。</p><p>　　一旦選擇了視頻進(jìn)行編輯，就會(huì)出現(xiàn)濾鏡屏幕。此視圖提供視頻預(yù)覽，用戶可以在其中選擇要應(yīng)用的濾鏡。有一個(gè)選項(xiàng)可

72、以保留視頻，因?yàn)樗恍枰獞?yīng)用任何濾鏡。當(dāng)選擇濾鏡時(shí)，應(yīng)用程序?qū)⒁曨l發(fā)送給GPU。這意味著CPU不處理視頻，因?yàn)镚PU可以作為單獨(dú)的線程工作。在處理視頻時(shí)，會(huì)顯示一個(gè)加載圖標(biāo)。該過程完成后，可以使用應(yīng)用的濾鏡查看已處理的視頻。如果用戶不喜歡應(yīng)用的濾鏡，他們可以選擇另一個(gè)濾鏡并重復(fù)上述過程。視頻處理完畢后，它仍保留在臨時(shí)目錄中。</p><p>　　第三個(gè)視圖是音頻視圖。該視圖顯示了一個(gè)經(jīng)典的iOSTableView

73、，其中列出了可供視頻選擇的所有可用歌曲。歌曲文件與應(yīng)用程序一起存儲(chǔ)，因?yàn)閼?yīng)用程序僅提供幾首歌曲，并且持續(xù)時(shí)間不超過20秒。當(dāng)用戶選擇一首歌曲時(shí)，視頻會(huì)再次被處理。該處理使用CPU創(chuàng)建一個(gè)并行線程，所以現(xiàn)在應(yīng)用程序繼續(xù)在主線程中運(yùn)行。用戶還可以選擇在視頻中不添加任何歌曲。音頻歌曲添加到視頻后，視頻再次保存在臨時(shí)目錄中。</p><p>　　第四個(gè)視圖提供了包含新音頻的視頻的最終預(yù)覽。在這里，用戶可以選擇將視頻保存到

74、相機(jī)相冊(cè)。請(qǐng)注意，到目前為止，視頻只存儲(chǔ)在臨時(shí)文件夾中。這是為了防止不必要地使用內(nèi)存空間和CPU，因?yàn)槭褂么鎯?chǔ)在應(yīng)用程序空間內(nèi)的臨時(shí)目錄中的文件更有效。</p><p><b>　　D.濾鏡</b></p><p>　　GPUImage在OpenGL著色器的基礎(chǔ)上工作。OpenGL著色器是設(shè)計(jì)用于在圖形處理器（GPU）的某個(gè)階段上運(yùn)行的程序。因此，我們的應(yīng)用程序可以使

75、用GPU處理視頻，并使用預(yù)定義的圖像濾鏡或使用OpenGL功能創(chuàng)建自定義濾鏡。</p><p>　　如前所述，當(dāng)應(yīng)用程序開始處理視頻時(shí)，CPU會(huì)創(chuàng)建一個(gè)并行線程。然后這個(gè)并行線程由GPU處理，如圖2所示。GPU讀取視頻的每一幀并分別處理每一幀。GPU處理完所有幀后，GPU將控制權(quán)返還給CPU。</p><p>　　圖2.處理視頻時(shí)GPU和CPU的狀態(tài)</p><p>

76、;　　OpenGL著色器用于處理圖像的過程稱為渲染管線。OpenGL渲染管線為這個(gè)著色器定義了多個(gè)階段，如圖3所示。</p><p>　　圖3.渲染管線的狀態(tài)</p><p>　　頂點(diǎn)著色器將視頻圖像轉(zhuǎn)換為單個(gè)頂點(diǎn)。原始程序集連接由頂點(diǎn)著色器創(chuàng)建的頂點(diǎn)以形成被稱為基本單元的圖形。然后應(yīng)用光柵化，將基元單位轉(zhuǎn)換為稱為片段的較小單位。在片段處理階段，將顏色和紋理應(yīng)用于片段，然后將其保存在幀緩沖

77、區(qū)中。幀緩沖區(qū)允許我們?cè)谄聊簧蟿?chuàng)建圖像或顯示圖像。使用OpenGL著色器的關(guān)鍵優(yōu)勢(shì)在于可以在GPU中并行運(yùn)行各種操作，從而實(shí)現(xiàn)更加靈敏的應(yīng)用程序。</p><p><b>　　3.結(jié)果</b></p><p>　　圖4顯示了應(yīng)用程序的第一個(gè)視圖。在此視圖中，用戶可以選擇兩個(gè)選項(xiàng)；使用iPhone相機(jī)錄制視頻或從相機(jī)相冊(cè)導(dǎo)入視頻。圖5顯示了用戶可以裁剪視頻的視圖。圖6顯

78、示了濾鏡可以應(yīng)用于視頻的視圖。該應(yīng)用程序目前提供了15個(gè)流行的濾鏡，如表1所示。</p><p>　　圖4.具有兩個(gè)可用選項(xiàng)的第一個(gè)應(yīng)用程序視圖</p><p>　　圖5.用于裁剪視頻的第二個(gè)應(yīng)用程序視圖</p><p>　　圖6.應(yīng)用濾鏡的第三個(gè)應(yīng)用程序視圖</p><p><b>　　表1.提供的濾鏡</b><

79、/p><p>　　圖7提供了一個(gè)視圖，用戶可以在其中選擇將被添加到視頻的音頻歌曲。目前，該應(yīng)用程序提供了10首音頻歌曲。這些歌曲已從jammendo.com下載，它們受Creative Commons的許可。最后一個(gè)視圖，如圖8所示，提供了經(jīng)過處理的視頻的預(yù)覽，并給用戶選擇將視頻保存在相機(jī)相冊(cè)中。</p><p>　　圖7.選擇音頻歌曲的第四個(gè)應(yīng)用程序視圖</p><p&g

80、t;　　圖8.保存編輯視頻的第五個(gè)應(yīng)用程序視圖</p><p><b>　　四.討論</b></p><p>　　A.使用GPU或CPU進(jìn)行圖像處理</p><p>　　在“方法”部分，我們提到了一起使用GPU喝CPU來(lái)處理許多任務(wù)。對(duì)于像視頻處理這樣的并行操作，使用GPU比CPU具有顯著的性能優(yōu)勢(shì)。在iPhone4上，GPUImage框架只需

81、要2.5毫秒即可從相機(jī)上傳幀，應(yīng)用伽馬濾鏡并顯示，而使用CoreImage執(zhí)行相同操作的時(shí)間為106ms，使用基于CPU的處理時(shí)為460ms。這使得GPUImage比CoreImage快40倍，比基于CPU的處理快184倍。在iPhone4S上，對(duì)于這種情況，GPUImage比CoreImage快4倍，比基于CPU的處理快了102倍。</p><p>　　CoreImage是Apple提供的用于處理圖像和視頻文件

82、的庫(kù)。在像iPhone6這樣的新型設(shè)備中，我們可以使用CPU或GPU實(shí)現(xiàn)相同的性能。但是，對(duì)于這項(xiàng)研究，我們決定使用GPU處理，因?yàn)楫?dāng)我們同時(shí)使用GPU和CPU進(jìn)行視頻編輯任務(wù)時(shí)，像iPhone4和iPhone5這樣的老設(shè)備會(huì)更加靈敏。</p><p><b>　　B.視頻的持續(xù)時(shí)間</b></p><p>　　Instagram和Snapchat等幾個(gè)社交網(wǎng)絡(luò)將可上

83、傳視頻的時(shí)間長(zhǎng)度限制在10秒或15秒。當(dāng)用戶使用移動(dòng)應(yīng)用程序時(shí)，他們需要快速、靈敏且無(wú)縫的用戶體驗(yàn)，處理超過20秒的視頻可能需要較長(zhǎng)的時(shí)間，從而對(duì)用戶體驗(yàn)產(chǎn)生負(fù)面影響。因此，我們決定將用戶可以使用該應(yīng)用程序的視頻的持續(xù)時(shí)間限制為20秒。表2顯示了使用具有不同視頻持續(xù)時(shí)間的應(yīng)用程序的視頻處理時(shí)間。所有視頻都是1080p，每秒30幀。對(duì)于這個(gè)實(shí)驗(yàn)，使用iPhone6應(yīng)用了模糊效果。</p><p>　　表2.iPho

84、ne 6上的1080p視頻處理時(shí)間</p><p>　　表3顯示了在640p中使用不同持續(xù)時(shí)間的視頻應(yīng)用程序的視頻處理時(shí)間（與表2中1080p視頻不同）。</p><p>　　表3.iPhone 6上的640p視頻處理時(shí)間</p><p>　　表4顯示了使用iPhone5s上的應(yīng)用程序來(lái)應(yīng)用模糊效果的視頻處理。所有視頻都是1080p，每秒30幀。如數(shù)據(jù)所示，iPho

85、ne5所需的處理時(shí)間幾乎是表2中iPhone6所需時(shí)間的兩倍。這是由于iPhone5s GPU的功能僅為iPhone6 GPU的一半。</p><p>　　表4.iPhone 5s上的1080p視頻處理時(shí)間</p><p><b>　　C.未來(lái)的工作</b></p><p>　　未來(lái)的工作將涉及提高應(yīng)用程序的可伸縮性。例如，我們將在服務(wù)器上存儲(chǔ)

86、歌曲列表。該應(yīng)用程序?qū)⒛軌蜻B接到服務(wù)器，歌曲可以下載到智能手機(jī)。另一項(xiàng)新功能將包括添加選項(xiàng)，以在不同圖像質(zhì)量的輸出視頻之間進(jìn)行選擇。使用較低質(zhì)量的導(dǎo)出視頻，與使用高質(zhì)量選項(xiàng)生成的視頻相比，處理速度會(huì)更快。</p><p><b>　　5.結(jié)論</b></p><p>　　移動(dòng)應(yīng)用程序和視頻內(nèi)容已成為我們生活中不可分割的一部分。人們經(jīng)常使用手機(jī)在社交網(wǎng)站上錄制、編輯和分