1、Computer Specialized English2022-6-28SEI.ECNU1Unit 8 Passage 3Desktop VideoComputer Specialized EnglishComputer Specialized English2022-6-28SEI.ECNU2Desktop video basics Definition Videos constructed and played using a personal computer Can be stored on a hard disk or distributed on CDs, DVDs, video

2、tapes, or the Web. Typically, the footage (片段） is captured by a video camera, or converted into digital format from videotape Although desktop videos do not quite reach the standard of DVD movies, you can use a consumer-quality camera and your PC to create videos that are suitable for a variety of p

3、ersonal and professional uses, such as a video scapbook of your children, a video wedding album footage 以英尺表示的長(zhǎng)度或距離， (電影或電視的)片段Computer Specialized EnglishNon-linear edit 非線性剪輯非線性剪輯, 指對(duì)視頻或音頻素材通過(guò)隨機(jī)存取的方式剪輯。與過(guò)去需要兩臺(tái)以上的錄像機(jī)，從不同的磁帶合成到一盤磁帶的線性剪輯線性剪輯方式相比，能立即重新排列、替換、增加、刪除、修改映像數(shù)據(jù)，以達(dá)到快速編輯的目標(biāo)。1990年代，隨著個(gè)人電腦運(yùn)算能力的提升

4、和普及，非線性剪輯已經(jīng)走入家庭或個(gè)人使用者。 非線性剪輯非線性剪輯是電影和電視后期制作中的一種現(xiàn)代剪接方式，它意味著能存取視頻片段中的任意一幀。它的概念類似于最初使用在電影剪接中 “剪”和“接”的手段。但是，在電影剪接的過(guò)程中，它是一個(gè)破壞性的過(guò)程，電影底片必須被剪斷。數(shù)字視頻技術(shù)出現(xiàn)后，產(chǎn)生了非線性、非破壞性的剪接手段。2022-6-28SEI.ECNU3Computer Specialized English2022-6-28SEI.ECNU4 Video is composed of a series of frames Frame A still picture which can b

5、e stored as a bitmap graphic Frame rate幀率,表示圖形處理器處理時(shí)每秒鐘能夠更新的次數(shù) The number of frames shown per second Most desktop video has a frame rate of 15 fps (frames per second). The bottom line for digital video viewing is that the faster equipment produces better results. Desktop video basicsComputer Special

6、ized EnglishBitmap 位圖位圖是使用像素陣列來(lái)表示的圖像，每個(gè)像素的顏色信息由RGB組合或者灰度值表示。根據(jù)顏色信息所需的數(shù)據(jù)位分為1、4、8、16、24及32位等，位數(shù)越高顏色越豐富，相應(yīng)的數(shù)據(jù)量越大。其中使用1位表示一個(gè)像素顏色的位圖因?yàn)橐粋€(gè)數(shù)據(jù)位只能表示兩種顏色，所以又稱為二值位圖。通常使用24位RGB組合數(shù)據(jù)位表示的的位圖稱為真彩色位圖。 BMP文件是微軟公司所開(kāi)發(fā)的一種交換和存儲(chǔ)數(shù)據(jù)的方法，各個(gè)版本的Windows都支持BMP格式的文件。Windows提供了快速、方便的存儲(chǔ)和壓縮BMP文件的方法。BMP格式的缺點(diǎn)是，要占用較大的存儲(chǔ)空間，文件尺寸太大。2022-6-2

7、8SEI.ECNU5Computer Specialized EnglishBitmap 例子： 位圖與其放大細(xì)節(jié)2022-6-28SEI.ECNU6Computer Specialized EnglishVideo Players Video playback requires a software player that is designed to work with the file format in which the video is stored. Players for most video file formats are available at no cost on t

8、he Web. The most popular players are Windows Medial Player and QuickTime. The former one is shipped with Windows and designed to be used on the PC platform. The latter is popular for both the PC and Mac platforms. 2022-6-28SEI.ECNU7Computer Specialized English2022-6-28SEI.ECNU8 The basic process of

9、producing your own desktop videos Shoot the video footage Transfer the footage to your computers hard disk Edit the video and soundtrack Output the video in its final format by selecting frame rate, window size, file format, and compression levelsfootage 以英尺表示的長(zhǎng)度或距離， (電影或電視的)片段Desktop video basicsCo

10、mputer Specialized English2022-6-28SEI.ECNU9 Popular Desktop Video File Formats AVI QuickTime movie MPEG RealMedia ASFVideo File FormatsComputer Specialized EnglishPopular Desktop Video File Format Format Extension PCPlayersDescriptionAVI (Audio Video Interleave).aviPCMicrosoft Media PlayerSometimes

11、 called “video for windows”, the most common format for desktop video on the pc platformQuickTime Movie.movPC/Mac/Unix/ LinuxQuickTime, Microsoft Media PlayerOriginally developed for the mac platform, today one of the most popular formats for web videosMPEG.mpg or .mpegPC/Mac/Unix/ LinuxMediaPlayero

12、ne of the most sophisticated digital video formats, used both for desktop videos and dvd moviesRealMedia.rmPC/Mac/Unix/ LinuxRealplayer, Microsoft Media Playerproduced by RealNetworks,is a popular format for streaming web videosASF (Advanced Streaming Format).asfPCMicrosoft Media PlayerMicrosofts vi

13、deo format for streaming video over the web2022-6-28SEI.ECNU10Computer Specialized English2022-6-28SEI.ECNU11Video cameras Digital video camera stores footage as a series of bits Digital Videotape formats miniDV,DVCPro,DVCam,MiniDV MiniDV is the most popular, and generally is the format used by cons

14、umer digital video camera.Computer Specialized EnglishConferencing Video Cameras You might be familiar with the small, inexpensive videoconferencing cameras that attach directly to a computer. These cameras capture video data in digital format. They produce very low-quality video, and because they m

15、ust remain tethered(通過(guò)繩子拴住的） to your computer, these cameras tend to limit your videos to “talking heads”.2022-6-28SEI.ECNU12Computer Specialized EnglishAnalog Video Cameras Can shoot the footage and store the video signal as a continuous track of magnetic patterns on tape. The three most popular an

16、alog video formats are Hi8, S-VHS, and VHS(producing lower quality video). None of these analog formats produces video that matches the quality of a digital video camera. 2022-6-28SEI.ECNU13Computer Specialized EnglishDigital Video Cameras A digital video camera captures video data in digital formal

17、, which can be directly transferred to a computer for editing. Digital cameras generally produce higher quality video than analog or videoconferencing cameras. Images tend to be sharper and more colorful. The higher the quality of the original video, the better the final video will look2022-6-28SEI.

18、ECNU14Computer Specialized English When desktop videos are processed and stored, some of the image data is eliminated to reduce the video file to a manageable size. Simpler videos tend to maintain better quality as they are edited, processed, and stored. Camera movements, fast actions, patterned clo

19、thing, and moving backgrounds all contribute to the complexity of a video, and should be avoided or minimized. 2022-6-28SEI.ECNU15Computer Specialized English2022-6-28SEI.ECNU16 Techniques help to produce video footage that maintains good quality as it is edited and processed Tripod(三角架) used to mai

20、ntain a steady image Move slowly Zoom in an out slowly Direct your subjects to move slowly Position your shot Ask the subjects to wear solid colored（純色的） clothingTips on producing good quality videos Computer Specialized English2022-6-28SEI.ECNU17Video transfer and storage Send the data over a cable

21、 Analog video footage must be converted into digital format before it is stored on the computers hard disk Video capture software to control the transfer processanalog 模擬(量, 裝置, 設(shè)備, 系統(tǒng), 計(jì)算機(jī)) analog transmission(遠(yuǎn)距離通訊中的)模擬傳輸digital 數(shù)字的,數(shù)碼的Computer Specialized English2022-6-28SEI.ECNU18Desktop video e

22、diting and processing Edit the video footage into the final desktop video using video editing software Video consists of video tracks containing video segments and transitions, plus audio tracks containing voices and music Color image at 1024*768 resolution requires 2359296 bytes for each frame reso

23、lution 清晰度, 析象分解力，分辨率Computer Specialized English2022-6-28SEI.ECNU19Using Cases Videoconferencing Windows Movie Maker for Win7 PhotostageComputer Specialized English2022-6-28SEI.ECNU20Videoconferencing A videoconference or video conference (also known as a videoteleconference) is a set of interactiv

24、e telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. It has also been called visual collaboration and is a type of groupware.Videoconferencing differs from videophone calls in that its designed to serve a conference

25、rather than individuals. It is an intermediate form of videotelephony, first deployed commercially by AT&T during the early 1970s using their Picturephone technology.Computer Specialized English2022-6-28SEI.ECNU21Windows Movie Maker for Win7Step 1: Find photographsStep 2: Watch a demo (optional) Step 3: Download Windows Movie Maker if not on your computer Step 4: Add photos to Movie Make