Video

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 201 visible
  image degradation occurs
• MPEG - Moving Picture Experts Group
• After a 501 compression rate video degradation
  occurs
• MPEG - is 2001
• P64

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 43
• PAL Phase Alternate Line used in Europe,
  Australia, South Africa
• SECAM- France, Russia
• HDTV 1280x720 (169) allows viewing in
  Cinemascope and Panavision movies. See
  www.atsc.org on latest.

13
Screen Sizes Ratios
14
Warning

• Todays multimedia monitors are 43
• (1024 x 768) or (800 x 600), but
• HDTV specifies a ratio of 169 (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