4 multimedia basics

1
About Multimedia
Introduction to Multimedia
What does multimedia mean to you?
Multimedia is any presentation that combines
several media such as text, animation,
graphics, sound, video and streaming
content.
Multimedia is the convergence of digital
media. This means media producers must
learn how to use multimedia to create content
for TV, radio, video, and the Web.

2
Types of Multimedia
Still Media
Any media or image that can be viewed
within one single frame or a single
image that does not change.
Examples: Photos or graphic
images, logos, etc.

3
Types of Multimedia
Dynamic Media
Examples: Animation, video, audio, etc.

4
Types of Multimedia
Interactive Media
Examples: Animation, Web sites, CD/DVD
authoring, software programming, etc.

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Types of Multimedia
Animation

6
Types of Multimedia
Digital Video

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Types of Multimedia
Digital Audio

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Types of Multimedia
Streaming Media
So what is streaming anyway?
Streaming software like RealServer or QuickTime
takes your video/audio file, segments it, and
sends the pieces to a buffer on your hard drive.
Then, the buffer renders the packets together to
play like a continuous file, resulting in a smooth,
high-quality track with a painless download time.

9
Types of Software
Software
Text and Graphics: MS Word, Macromedia
Freehand, Adobe Illustrator, Adobe
Photoshop (bitmap), Macromedia Flash
(vector-based)
Animation: Macromedia Flash and Director
Digital Video: iMovie2, Adobe Premiere,
Final Cut Pro

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Types of Software
Software
Digital Audio: Pro Tools, Sound Forge,
iTunes
Streaming: QuickTime, RealServer
Third-Party and Others: Adobe AfterEffects
(add filters & effects to video), Cleaner 5
(encoding/compressing video, audio, etc.),
Real Media, Sorenson Pro

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QuickTime
What is QuickTime?
It’s a file that tells the computer what kind of
media to present and when to present it.
The software is a gateway for distributing
media including images, music, MP3 and
more.
QuickTime lets you experience more than
200 kinds of digital media with a Mac or PC.

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Hardware and Equipment
• Windows PC/Mac G4
• 300-512 Mb RAM
• 30-40 GB Hard Drive
• CD ROM, DVD RAM (CD-R, DVD-R)
• Two 17” Monitors
• FireWire or ATA Drives (30+ GB)
• Removable Media

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• 3CCD Digital Video Camcorder (Sony, Canon)
• Digital Still Camera - 3-5 mega pixels* (Nikon, Sony)
• Converter or Deck (from DV to SVHS)
• Scanner (Hewlett Packard, Epson)
• Printer (optional)
* high-end

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End of Presentation
More Information
• For software, visit www.macromedia.com (free 30-
day trials of Flash, Dreamweaver and more!)
Other Links:
• www.cnet.com (latest prices, tutorials, and more)
• www.techsoup.org (CompuMentor’s site)
• Presentation by: Nettrice R. Gaskins, current Director of the BNN
Multimedia Center & President of DigitalArt Communities, Inc.
Email: nettrice@onebox.com

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Multimedia in the past…
For VIDEO:
VCRs, Laserdiscs, videodiscs
For SOUND:
cassette player or stereo system
For GRAPHICS:
Film Slides or OHPs
For TEXT:
as OHPs (overhead projectors)

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Definition of Multimedia
Interactive multimedia
means that all of
these elements are put
together is such a way
that the user can control
all or some aspects of
your software.
Multimedia is a collection of various elements
called media that when combined form a single unit.
These media elements include
video, sound, graphics, animation, and text.
The multimedia
designer’s job is to
put together a
product that is both
easy to use and
interesting.

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Convergence of industries & technologies
 Multimedia is the convergence of different
technologies. Technologies of sound, video,
graphic design, publishing and animation
combine in an interactive way in:
 Web applications (publishing, streaming
audio, hypertext, graphic design)
 Movies (digital video, animation)
 CD ROM development (audio, PC, DVD)

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Applications of Multimedia
 Games Industry - PC, Video console, etc.
 Entertainment – Television, movies
 Education – Educational software, interactive
programs
 Training and Development

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Multimedia PC Specification
 750-MHz processor
 64 MB RAM
 DVD drive recommended for Consumer & Office
systems; required for Entertainment PCs.
 CD ROM Rewritable (for creation of multimedia)
 56-Kbps V.90 modem (Consumer and Entertainment)
 17” monitor, 3D graphics accelerator card
 Speakers with sound card
 LOTS of hard drive space

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Creating Multimedia - Hardware
In order to create a multimedia application, you will access to:
 Microphone and speakers
 Scanner (capture images)
 video capture card (capture video)
 VCR (play video to be captured)
 Digital camera / still camera (capture images)
 Connection to the internet (capture images/text,
research)

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Creating Multimedia - Software
In order to create multimedia application, you
will need:
 Macromedia Director
 Image editing software – Fireworks,
Photoshop, Paint Shop Pro, etc.
 Sound editing software – Cooledit, etc.
 Video editing software – Adobe Premier,
Videowave, etc.
Try www.download.com for trialware or
shareware of sound, image or video
editing software.

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Creating Multimedia - Skills
In order to create multimedia application, be:
Organised. Creating a multimedia project
is time-consuming. You must be
organised and set time-goals for
yourself.
Creative. Spend time analysing other
software and websites. Search for
graphic design techniques, etc.

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Standards
There are no standard multimedia
platforms, however there are multimedia
standards on individual platforms.
Examples include QuickTime (originally
Apple), AVI, MP3, MPEG, JPG, GIF, PAL,
NTSC, etc.

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What is multimedia?
 A computer-based interactive
communications process that
incorporates:
– text,
– graphics,
– sound,
– animation, and
– video.

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Why Multimedia?
 User control
 Individualization
 Interactivity

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Interactivity: the Key
Component
 Learner Control: The user determines
what content is delivered, when it is
delivered, & how it is delivered.
 Nonlinear:
 Linear:

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Categories of Multimedia
Titles
 Entertainment
 Education: A.D.A.M.
 Corporate Communications
– Marketing & training
– Presentations & training
 Reference

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Categories of Multimedia
Titles (Continue)
 Edutainment
 Training
 Recreation

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Delivering Multimedia
 Compact Disc (CD)
 Digital Video (Versatile) Disc (DVD)
 Kiosk
 Online (Internet & Intranet)

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Multimedia Personal Computer
 MPC: Level 1 (1990)
 MPC2: Level 2 (1991)
 MPC3: Level 3 (1993)
– 8MB
– Pentium 75 MHz
– 540 MB Hard Drive
– 4X Speed CD-ROM
– 640x480 Pixels Video Display (65,536
colors)

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Playback System
 Processor
 Memory
 Monitor & Video Card
 Audio Card
 CD-ROM Drive & DVD-ROM Drive

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Development System
 Processor
 Memory
 Video capture card
 Monitor

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Development System (Continue)
 Peripherals
– Scanner
– External storage
 Zip drive (100 MB)
 Jazz drive (1 GB)
– CD, DVD recorder
– Digital camera, Digital Video Camera
– Microphone
– other

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What is Multimedia?
• Human behavior – sensory, memory,
reactionary
• Five senses – sound, touch, sight, taste,
smell
• A combination of these provides a rich
learning environment
• Only sound and sight can be captured in
computer systems (why?)

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What is Multimedia?
• Sight and sound are captured in a
computer system as video, audio,
and data
• A medium refers to any one of data
such as text, digitized voice, digitized
video, still digitized images, and
graphics.

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What is Multimedia?
Multimedia
- is the combination of two or
more media.

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User perspective
• The user gets input in the form of
data, voice, video, image, graphics,
or a combination of these
• The user generates information in
one or more of these media

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User perspective
U
S
E
R
Data
Voice
Video
Image
Graphics
Data
Voice
Video
Image
Graphics

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What is a Multimedia
System?
• A multimedia system is characterized by
the creation, processing, storage,
manipulation, rendition and distribution of
multimedia information
• Temporal relationship (time) between
media makes multimedia different from
normal data
– synchronization

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Multimedia System
Requirements
• Very high processing power -
processing and movement of large
amounts of data in real-time
• File system capable of handling
multimedia information
• File formats that exploit the inherent
properties of the multimedia
information

42
Multimedia System
Requirements
• Efficient and high I/O rate
• Multimedia operating system
• Storage and memory
• Network support
• Software tools and applications

43
Analog vs Digital Signals
• Voice, music – analog signal –
continuous
• They must be digitized for computer
manipulation
• Conversion is carried out by signal
encoder
• Signal decoder

44
Sampling
• E.g. voice can be sampled at 11 KHz,
22KHz, 44KHz
• Music has a higher range.
• Human hearing 20-20,000 Hz
• CD quality sound is 44KHz

45
Quantization
• 1bit = 1 Binary Digit
• 8 bits = 8b = 1 byte = 1B
• 1000B = 1KiloBytes = 1KB
• 1000KB = 1 MegaByte = 1MB
• 1000MB = 1GigaByte = 1GB
• 1000GB = 1 TeraByte = 1TB
• …

46
Binary Code
Decimal Binary
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001

47
Quantization
• The value of each sample is also
represented digitally
• In the discrete domain not all the
values of the continuous domain can
be found
• How many bits are sufficient?
• Music – 16 bits
• Pictures – 24 bits

48
Types of Media
• Discrete
– Text
– data
– image
– graphics
• Continuous
– Audio
– Video

49
Text and Data
• Numbers can be converted from
decimal to binary
• Characters can be converted using a
look up chart called ASCII
• Each character is assigned a decimal
number e.g. A = 65
• Data files are usually small

50
Graphics
• Graphics are constructed by the
composition of primitive objects such as
lines, circles, polygons, curves, and
splines
• Each object is stored as an equation
• Each object has a number of attributes
– shape
– size
– color (border)
– color (fill)
– shadow etc

51
Graphics
• Takes less space than bitmaps for
uncomplicated pictures
• Not suitable for photographs with a
lot of shades etc.

52
Images
• Continuous-tone pictures are
digitized
• Images are bitmaps
• Divide the picture into pixels –
picture cells
• E.g. 100 x 100
• Each pixel has a n bit quantization
• N = 1, 2, 4, 8, 16, 24

53
Images
Bits Number of
colors
1 2
2 4
4 16
8 256
16 65536
24 16777216

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Color
• Three primary colors - RGB
• Additive color mixing leads to a color
gamut
• eg. Black = 0R + 0G + 0B
• Java applet to mix colors
http://www.phy.ntnu.edu.tw/java/image/rgb
Color.html
• Java applet to display color gamut
http://www.cs.rit.edu/~ncs/color/a_chroma.
html

55
Aspect Ratio
• Screen width / screen height
4
3
4/3 = 1.33

56
Audio
• Sampling rate and quantization
• Mono, stereo or surround (number of
channels)
• CD specification
• DVD specification

57
CD-DA
• CD - Digital Audio
• Stereo, 44KHz Sampling, 16 bit
quantization
• 73 minutes of music on CD

58
Surround Sound• Mono - one channel
• Stereo - Two channels
• Five channel - Left , center,
right, left surround, right
surround

59
Video
• Most colors of the visible spectrum
can be constructed from three
primary colors
• Red, Green, Blue RGB
• Each uses an 8 bit representation
• 256 levels of each color
• Total 24 bit = 16 million colors

60
Video
• Frame rate – 12, 15, 25, 30
frames/sec
• NTSC video uses 30 frames / sec
• NTSC has 4:3 aspect ratio
– Length/height = AR
– 1, 1.33, 1.66, 1.85, 2, 2.5 etc.

64
Letterbox
• When showing a widescreen movie
on a 1.33 screen, letterboxing is
used to display the entire frame

65
Pan and Scan
• Broadcast television uses pan and
scan to utilize the entire height of
the screen thus losing information on
the sides

Definition of Multimedia
Multi (Latin multus - numerous)
Media, medium (Latin medius, medium: middle, center,
intermediary; Latin mediat: intermediary, means)
Multiple types of information captured, stored,
manipulated, transmitted, and presented.
Specifically: Images, Video, Audio (+Speech) and Text
Related terms: hypermedia, hypertext
Problem: “hypertext”, “hypermedia”, “multimedia” so
overused/generalized they now convey little meaning

Top Ten Misconceptions about
Multimedia Computing
Ramesh Jain, founding chairman of Virage and CTO of
Praja, www.praja.com, presented the following “top ten”
MISCONCEPTIONS list as part of his keynote speech at
the ACM Multimedia Conference, Ottawa, Canada,
October 2, 2001:
10. Video = Multimedia.
9. Multimedia = multi X separate medium.
8. All information is ONLY in the images or video.
7. Editing of media is almost always off-line.
6. Query by example is best access method.

Top Ten Misconceptions about
Multimedia Computing, Continued
5. All users have PhDs in multimedia computing.
4. Users have no memory or context.
3. Computers are for computing.
2. Medium is the message.
1. We work for computers.
Ramesh Jain concluded his keynote talk with the
observation:
Information Builds Experience, Experience is Life.

Audio
Images
Information
Retrieval
Storage
Systems
Networking Psychology
HCI
Data
Compression
Natural
Language
Processing
Multimedia
CPU Power
Video

Multimedia Physics
• Sound is a waveform
• Imagery is a waveform
• light is electromagnetic radiation with different intensity in
spatial coordinates
• color corresponds to wavelength (red is the longest
wavelength visible by people)
• Introductory treatment of “light behaves as both particle
and wave” at http://www.howstuffworks.com/light1.htm
• “Distributed Multimedia” by Palmer Agnew and Anne
Kellerman, published by Atomic Dog Publishing,
http://www.atomicdogpublishing.com

A Quick Introduction to Light Waves
• Derived from:
http://www.pbs.org/deepspace/classroom/activity2.html
• Waves characterized by wavelength and frequency
• Light is a type of electromagnetic radiation in a range for which our
eyes are sensitive
• Sound is not electromagnetic radiation, but sound is a wave as
well. Higher pitches are caused by higher frequencies of vibrating
molecules that reach your eardrum. Lower pitches are likewise
caused by lower frequencies.
wavelength

Wavelength/ Frequency Spectrum
Long radio waves Microwaves X-rays Gamma rays
TV, FM Infrared Ultraviolet
700 nm 600 nm 500 nm 400 nm
4.5x1014 Hz 5x1014 Hz 6x1014 Hz 7x1014 Hz

Migration from Analog to Digital Representation
• Analog signals to sensors
• E.g. vinyl records
• Fidelity is faithfulness to the original
• Digital representation (1960s)
• Sampling
• Quantizing
• Coding
• Limiting factors in move to digital:
• Storage limits
• CPU speeds
• I/O speeds
• Network bandwidth

Why Digital?
• Universal storage, transmission format
• CD, Internet
• Precision (range of values, number of bits, floating
point)
• Lossless transmission/storage
BUT:
• Sampling rate distorts information
• Size requirements may be huge compared to analog,
e.g., 4.2 million pixels for single 35 mm photograph!
 results in lots of work on perception-based lossy digital
compression strategies

Why Perception Matters
http://www.libertarian.on.ca/images/Florida%20Recount.jpg

Audio
• Sounds
• Hear 15 Hz to 20 kHz
• Speech is 50 Hz to 10 kHz
• Speech Recognition
• It is hard to wreck a nice beach / It is hard to recognize
speech
• Ice cream / I scream
• Synthesis
• Speech
• Music
• MIDI for 127 instruments, 47 percussion sounds
• Notes, timing

Speech Recognition Issues
• Continuous vs. discrete
• Vocabulary size
• Channel (microphone)
• Environment (location of microphone and speaker)
• Speaker dependent/speaker independent
• Context (language model)
• Interactivity (dialog model)

Acoustic Modeling
Describes the sounds that
make up speech
Lexicon
Describes which
sequences of speech
sounds make up
valid words
Language Model
Describes the likelihood
of various sequences of
words being spoken
Speech Recognition
Speech Recognition Knowledge Sources

Speech Variations
Style Variations
careful, clear, articulated, formal, casual
spontaneous, normal, read,
dictated, intimateVoice Quality
breathy, creaky,
whispery, tense,
lax, modal
Context
sport, professional,
interview,
free conversation,
man-machine dialogue
Speaking Rate
normal, slow, fast,
very fast
Stress
in noise, with increased vocal
effort (Lombard reflex),
emotional factors (e.g. angry),
under cognitive load

Video
• Video is made up of frames
• Frame rate = delay between successive frames
• Minimal change between frames
• Sequencing creates the illusion of movement
• 16 frames per second (fps) is “smooth”
• Standards: NTSC 29.97 fps, PAL fps, HDTV 60 fps
• Interlacing
• Display scan rate is different
• Monitor refresh rate, e.g., 60-70 Hz = ~1/second

Captured vs. Synthetic
• Animation vs. Video
• Vector Graphics vs. Bitmap/Raster Pictures
• Synthesizer vs. Recording
• Storage? Manipulation? Processor Requirements?
• Fidelity to real world
• Hybrids are possible

Why is Multimedia Important?
• Our society -
• captures its experience,
• records its accomplishments,
• portrays its past
• informs its masses
……in pictures, audio and video
• For many, CNN has become the “publication of record”
• Multimedia learning leverages “multiple intelligences”
• Multimedia Digital Libraries are an essential component
of
• formal, informal, and professional learning
• distance education, telemedicine

Technology Push vs. Market Pull
• Home Entertainment
• Catalog Ordering
• Multimedia Training, Education
• Videoconferencing
• Professional Video Services
• Videomail
• Speech Recognition

Hype vs. Reality
What is feasible, under what circumstances?
What is possible?
What is impossible?
What is unlikely?

4 multimedia basics

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4 multimedia basics