Understanding Multimedia Elements

1
Understanding Multimedia Elements Sound,
Animation, Video

• Unit C

2
Objectives

• Understand sound
• Sound on the Web
• 2-D animation
• 3-D animation
• Animation on the Web

3
Objectives

• Video
• Video compression video editing
• Video on the Web

4
Understanding Sound Analog

• Sound waves
• Analog wave pattern
• Volume height of each peak
• Higher the peak, louder the sound
• Frequency(pitch) distance between peaks
  measured in hertz(Hz)
• Greater the distance, lower the sound

5
Understanding Sound Digital

• Converted to bits via sampling
• Quality depends on
• Sample rate number of times sample is taken
  (11.025 kHz, 22.05 kHz 44.1 kHz)
• Sample size amount of information stored (8 bit
  and 16 bit)

6
Digitizing Process

• Cassette tape player, videotape player, CD or
  microphone is captured by sound card
• Software/user controls sample rate and size
• Sound-editing program used for manipulation

7
Sound File Formats

• WAV
• Windows or Macintosh
• Used on the Web
• AIFF (Audio Interchange File Format)
• AIFFC (AIFF Compressed)
• Windows or Macintosh
• RealAudio (.ra)
• Allows streaming of sound over Web
• MP3 (MPEG Layer 3)
• Compresses entire songs for Web
• Near stereo quality

8
MIDI Sound Files

• Musical Instrument Digital Interface
• Electronic musical instruments create sound then
  stored on computer
• Contain code/commands, not digitized sounds
• Very small files

9
Sound on the Web

• File size is an issue
• File compression used for certain file formats
  (RealAudio and MP3)
• Sounds stored on Web server
• Media player installed on user computer
• RealPlayer, Windows Media Player, MP3, QuickTime

10
Streaming Media

• Audio and video can be played in real time
• File starts playing immediately doesnt wait
  for full download
• Connection to web server is continuous

11
Tips for Using Sound on Web

• Is the sound appropriate? Is there a benefit?
• Is it a good sound quality?
• Can you afford the cost of recording the sound?
• Should you just use sound with still images
  instead of video?
• Can you stream the files?
• Can you give the user control?

12
2-D Animation Can Provide
Simulation of actual events
Action and realism in entertainment
Visualization and demonstration in education
13
2-D Animation Issues

• Movement is made up of many still images
• Each still image has its own frame
• Speed of moving these frames
• Movies on film 24 fps
• Television 30 fps
• Computer animation 12-15 fps

14
2-D Animation Types Cel Animation

• Based on changes that occur from one frame to
  another
• Background image is stationary
• Celluloid images placed on background
• Celluloid images change from frame to frame

15
2-D Animation Types
Cel Animation
16
2-D Animation Types Path Animation

• Object moved along predetermined path on screen
• Object can stay the same, be resized or rotated
• Tweening in an authoring program
• Define beginning position in one frame
• Define ending position in another frame
• Software fills in intervening frames

17
2-D Animation Types
Path Animation
18
2-D Animation Software Allows

• Frame rate changes
• Transitions
• User playback control
• Looping
• Object drawing and animating
• Sound clips

Cheap shareware to expensive authoring packages
19
3-D Animation

• Games and adventure titles
• Users are participants, not spectators
• Much more complex than 2-D
• Involves
• Modeling
• Animation
• Rendering

20
3-D Modeling and Animation
Draw views by setting points on a grid
Create contours and structure
Define objects motion, lighting perspective
views
21
3-D Rendering

• Give objects attributes
• Colors
• Surface textures
• Transparency amounts
• Programs
• Strata 3D
• LightWave 3D
• 3D Studio Max
• Maya
• Houdini

22
3-D Morphing
23
Warping

• Distort a single image
• Change a frown into a smile

24
Virtual Reality (VR)

• Creates an environment that surrounds the user so
  the user becomes part of the experience
• Examples
• Boeing Corporation flight simulators
• CD-based adventure games Myst and 7th Guest
• Virtual tour sites
• Some require special equipment like goggles
  gloves

25
Animation on the Web

• Animated text
• Animated GIF
• Macromedia Director applications
• 3-D environments

You must have the plug-ins to play these
animations!
26
Animated Text on the Web

• Rotating, zooming, scrolling, distorting,
  blinking
• Use authoring software
• Use HTML
• ltblinkgtHellolt/blinkgt

Scrolling Text
Scrolling Text
Scrolling Text
27
Animated GIFs on the Web
Each .gif image file is a little different
28
Macromedia Applications on the Web
Director or Flash to author
Shockwave to deliver on Web
29
VRML

• Virtual Reality Modeling Language
• Creates interactive 3-D on the Web
• User is moved through the environment (instead of
  object moving)
• Environment is dynamic and always changing

30
Understanding Video

• Video can be
• Very expensive
• Time-consuming to create
• Very large files
• Video can be found in stock film companies
• Video must be digitized from an analog signal

31
Digitizing an Analog Video Signal
32
Editing Video

• Digitized video is not linear like analog video
• Can access any part of video randomly
• Can cut and paste
• Can use special effects and transitions

33
Digital Video File Size Considerations

• 1 second of high-quality color video on ¼ of the
  computer screen 1 MB file size
• Determining file size
• Frame rate lower the better (15 fps minimum)
• Image size use smaller playback window
• Color depth 8-bit vs. 16-bit vs. 24-bit color

34
Video Compression/Decompression

• Codecs
• Lossless gives larger file by preserving exact
  image
• Lossy eliminates some image data smaller file,
  but poorer quality

35
MPEG Compression Format

• Motion Pictures Experts Group
• Reduce file size by eliminating redundant
  information (backgrounds)
• Also looks for changes from frame to frame

36
Video Compression Software

• Apples QuickTime and QuickTime for Windows
• Dual platform
• Lossy compression
• Microsoft Windows Media Player
• AVI format
• Both synchronize sound and motion
• Synchronized Multimedia Integration Language
  (SMIL)
• Markup language like HTML

37
Video Editing Software
Adobe Premiere

• Transitions dissolves, wipes, spins
• Animations fly-in logo
• Special effects twisting, zooming, rotating
• Filters color balance, brightness/contrast,
  blurring, distortions, morphing

38
Video on the Web

• Only practical for 56K or higher connections
• Planning
• Is animation or still images with sound better?
• Are stock videos better?
• Quality-versus-cost and relevance of video to
  application

39
Video Transfer Types HTTP

• HyperText Transfer Protocol
• Downloads entire video to hard drive of user
• User can play it over and over quickly
• Better for small video clips

40
Video Transfer Types RTSP

• Real-Time Streaming Protocol
• Continuous playing/streaming
• Not saved on hard drive
• User can randomly access any video part
• Better for large videos and live broadcasts

41
Streaming Video

• HorizonLive live video presentations

42
Video and Virtual Reality

• Apple QuickTime VR system
• iPEX system
• Starts with panoramic photographs
• Camera rotated after each picture for 360 degrees
• Photographs electronically stitched together
• User can navigate and zoom (White House site)

43
Issue The Napster Controversy

• Intellectual Property Rights and Emerging Web
  Technologies
• Sharing MP3 files through the web
• Recording Industry Association of America filed
  suit

44
Understanding Multimedia Elements Sound,
Animation, Video

• End