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Video. Multimedia Systems John Sullivan. Using Video. “Full-Motion video on personal computers changes everything. It is like turning a ten-speed bicycle into a Harley-Davidson.” David Bunnell, Editor-in-chief, New Media Magazine

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  1. Video Multimedia Systems John Sullivan

  2. Using Video “Full-Motion video on personal computers changes everything. It is like turning a ten-speed bicycle into a Harley-Davidson.” David Bunnell, Editor-in-chief, New Media Magazine “resort to video only when all other methods pale by comparison” David A. Ludwig, Interactive Learning Design

  3. Using Video Digital Video most engaging of multimedia venues, and it is a powerful tool for bringing computer users closer to the real world. A clip of J.F.K proclaiming, “Ich bin ein Berliner” in video and sound is more compelling than scrolling text field. (Vaughan, 2002)

  4. Video Production for Multimedia • Digital Video • QuickTime and AVI • Interleaving Sound and Video • Capturing and Editing Video • The Process of digitizing video is known as capturing (or sampling)

  5. Video Compression • Digitizing a 10-second video clip at full screen, 24 bits, full-motion requires the storage and transfer of a very large amount of data. • To reproduce one frame of digital video at 24 bits requires approximately 1Mb of computer data. • Of 1.8 gigabytes of memory per minute • The longer the video the more RAM you will need. • This presents a bottleneck therefore compression is needed

  6. Data transfer rate • Hard disk transfer rates range from 1Mb to 10Mb per second. Even though this speed is the highest available, it falls short of the 30Mb per second required for full-motion uncompressed video.

  7. More on Compression • Full-size, full motion video requires that the computer delivery data at about 30MB per second. • Typical hard disk drives transfer data at only about 1 MB per second, and a quad speed CD-ROM player at 600K per second. • This technological bottleneck is currently being overcome by digital video compression schemes or codecs (coders/decoders). A codec is an algorithm used to compress a video for delivery. • Cinepack, RealVideo,

  8. Types of Compression • JPEG - Joint Photographic Experts Group • After a compression rate of about 20:1 visible image degradation occurs • MPEG - Moving Picture Experts Group • After a 50:1 compression rate video degradation occurs • MPEG - is 200:1 • P*64

  9. Video Capture and Playback in Multimedia Applications • To achieve the most effective results, you must consider 5 main parameters: • Data transfer rate of the storage media • Video window size • Video frame rate • Image quality and resolution • Storage capacity of delivery media

  10. Video Capturing • Adobe Premier • File • Capture • Movie • Instructions

  11. Obtaining Video Clips • Consider whether you should shoot new footage or acquire preexisting content. • Acquiring footage that you do not own can be a nightmare – it is expensive, and licensing rights and permissions may be difficult. • Each second of video could cost $50 to $100 or more. • Even a “public domain clip” from the National Archives will cost a minimum of $125 to copy the footage, and turnaround time is up to six weeks

  12. Broadcast Video Standards NTSC – National Television Standards Committee (1952). US and Japan Single frame is made up of 525 horizontal lines drawn every 1/30 of a second by 384 vertical lines (512x384) or 4:3 PAL – Phase Alternate Line used in Europe, Australia, South Africa SECAM- France, Russia HDTV – 1280x720 (16:9) allows viewing in Cinemascope and Panavision movies. See www.atsc.org on latest.

  13. 512 x 384 (4:3) Safe Title Area HDTV 1280 x 740 (16:9) 35 mm slide/photo 768 x 512 (3:2) NTSC television over scan Approx. 648 x 486 (4:3) 640 x 480 Monitor Screen Sizes Ratios

  14. Warning Today’s multimedia monitors are 4:3 (1024 x 768) or (800 x 600), but HDTV specifies a ratio of 16:9 (1280 x 720), much wider than tall. There is no easy way to stretch and shrink existing graphics to fit this aspect ratio, New multimedia designs and interface principles will need to be developed for HDTV

  15. Interlacing • On TV screen, the electron beam makes two passes as it draws, first the odd lines then the even lines – they are interlaced • On RGB monitor – single pixel lines are painted one-pixel thick and are not interlaced. • Interlacing on the Web is different it describes the progressive download giving the image the impression of becoming focused

  16. Video Capture Boards Pinnacle – a sophisticated audio board will allow you to use CD-quality sounds. Install a super-fast RAID (Redundant Array of Independent Disks) to support high-speed data transfer rates.

  17. References • Vaughan, T. (2002). Multimedia: Making it Work, New York: McGraw Hill • Tannenbaum, R. (1998), The Theoretical Foundations of Multimedia, New York: Computer Science Press,

  18. The End of Video By John Sullivan Updated Fall 2002

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