《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 5.1Different Video Attributes 5.2Common Video File Formats 5.3Balancing between File Size and Video Quality 5.4Making Video Elements Fit our needs 5.5Capturing Video 5.6Converting Video Elements from One File Type to Another 5.7Editing and Processing of Videos Chapter 5 Video

2 Discussion:  Have you ever captured, edited or processed video files ？  Do you know any of the attributes of video files ？  Do you know the uses and characteristics of different video formats ？  Do you know how to compress video files?

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 Video Standards Frame and Frame Sizes Frame Rate Bit Rate （ Bandwidth ） Codec 5.1Different Video Attributes

4 5.1Different video Attributes  Video Standards Different countries in the world have been using different video standards for broadcasting  The TV display standards in the world TV display standard Full Name Countries PAL Phase Alternate LineUnited Kingdom, Europe, Hong Kong, Mainland China, Singapore, Australia NTSC National TelevisionUnited States, Japan, Taiwan SECAM Standards Committee France, Russia

5 5.1Different video Attributes  Frames and Frame Sizes Digitized video is similar to movie film in concept, which consists of sequence of frames(which differs only slightly from the previous frame) accompanied with an audio track. The large the frame size of a digitized movie, the more image details is involved, and the more storage is needed.

6 5.1Different video Attributes  Frame Rate The frame rate is the number of frames or images that are projected or displayed per second, usually measured in framed per second(fps) Animation: frame rate demonstration Animation: frame rate demonstration

7 5.1Different video Attributes  Bit Rate （ Bandwidth ） The bit rate (measured in bps, bit per second(bandwidth) during video encoding

8 5.1Different video Attributes  Compression/Decompression(Codec) Compression （壓縮） / Decompression （解壓） Codec is an algorithm, or specialized computer program, that reduces the number of bytes consumed by large files and programs. Compression － can reduce the amount of data needed to reproduce video. It can save storage space, increase access speed. The contents of a compresses video file cannot be displayed without the appropriate Codec installed Original video （ large ） Compressed video file Decompressed video file 儲存 The idea of video compression and decompression 播放DecompressionCompression

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 AVI (Audio Video Interleaved) MPEG (Moving Picture Experts Group) RealVideo (RV) and Video Streaming QuickTime (MOV) 5.2 Common Video File Formats

Common Video File Formats  AVI (Audio Video Interleaved) It is a sound and motion picture file format for Microsoft’s video for Windows It is one of the earliest video formats in Windows It gains strong support from many video editing software The file size is extremely large

Common Video File Formats  MPEG MPEG stands for Moving Picture Express group, which develops standards for digital video and audio compression under the International Organization for Standardization (ISO) MPEG achieves high compression rate by storing only the changes from one frame to another, instead of each frame

Common Video File Formats StandardOriginally developed for Maximum resolution Common encoding bit rate Remarks MPEG-1 (1992) Video CDs and interactive CD- ROMs 352 x 288 (PAL) 352 x 240 (NTSC) 1.5 MbpsVideo slightly better than VHS with near-CD audio quality MPEG-2 (1994) DVD, digital TV broadcast 720 x 576 (PAL) 720 x 480 (NTSC) Variable bit rate up to 4 Mbps Full screen video with broadcast quality MPEG-3 High Definition TV(HDTV) Obsolete and have merged with MPEG-2 standard MPEG-4 (1998) Specifying a description of digital AV scenes in the form of ‘AV objects’ that have certain relations in space and time From 64 kps up to 4 Mbs depending on available bandwidth MPEG-4 goes beyond MPEG-1 and MPEG-2 which works with “frame-based video” and audio MPEG-4 also commonly used as codec for AVI files

Common Video File Formats  Real Video(RV) and Video streaming Developed by Real Networks, Inc. Aims at providing smooth delivery of video on the web with tailor-made quality Supports video streaming so that a user does not have to wait to download the whole video file before watching it

Common Video File Formats  QuickTime (MOV) QuickTime is a popular audio, video and even virtual reality(VR) formats Supports VR format which can display 360° panoramic scenic

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 5.3 Balancing between File size and Video Quality  The larger the file size, the better the video quality will be  Factors that affect video quality Frame size Frame size Frame rateFile size Frame rateFile size codec and codec bit rate （ quality ） codec and codec bit rate （ quality ）

16 Factors that affect video quality Codec and codec bit rate codec bit rate Frame size File size Frame rate Video quality

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 5.4 Making Video elements Fit our Needs Recommended Video Format （ Codec ） SituationVideo Delivered from Channel bandwidth Real VideoMPEG-1MPEG-2AVI Present ation Local harddisk of notebook or desktop computer From 6 MB/sto over100MB/s  Network video Network video server distributed over a local area network 10 Mbps  100 Mbps   (DivX,MPEG-4) Web video Web video server distributed over the web From 56 Kbps(dial-up) to 3 Mbps(broadba nd)   (DivX,MPEG-4)

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 5.5 Video Capture We can use video card or other devices to convert analogue video signal(e.g. VHS tape) to digital format. It can be used in multimedia presentation.

《高中電腦與資訊科技》 選修單元丁：多媒體製作及網頁編寫 5.6Convert the digital file format A5.6.1 Use Ulead MediaStudio Pro/Ulead Video Studio Change AVI / RealVideo file to convert to MPEG file A5.6.2 Use Helix Producer Change AVI / MPEG / QuickTime file to RealVideo file