2. Multi-Media
• Multi Media describes several forms of
media which combine to communicate
more effectively than they would
separately.
• Example –text and film
Photos and Sound.
3. Why is Multimedia better than
“Traditional Media”
• Traditional media could be defined as:
• Books /Magazines /Audio /Video
8. Modern Multimedia
• Good Multimedia combines media
elements to communicate MORE
effectively than traditional media types
9. Characteristics of Multimedia that make it
more effective in communicating
• It caters to different learning styles as
some people learn better from listening, or
seeing or reading.
• Good multimedia will combine these or let
the user choose the form of instruction.
• Good multimedia will engage the user by
letting them choose the topic or area of
interest directly.
10. Cont.
• Multimedia allows learners to choose the level of
difficulty that suits them best, unlike a book or a
teacher who must teach to 1 audience.
• It allows learners to choose the pace of
instruction –fast for strong learners, slow for
those having difficulty.
• It allows the repeating of information as many
times as necessary for learners having difficulty
12. Consistency
Users expect that different applications will
have a sameness to them which means
knowledge is transferable to a similar
product. Ie Disk symbol means save on
most programs
• Also consistency is when buttons are in
the same place from page to page or form
to form.
13. Feedback
• Feedback describes elements that gives
the user a response. Example: buttons
clicked make noises. A progress bar
showing how long until a process is
completed.
14. Forgiveness
• High forgiveness allows users to undo
mistakes or undo previous decisions in a
program. All actions should be reversible.
15. Aesthetics
Aesthetics means its level of attractiveness.
Good multimedia should:
• Have adequate amounts of whitespace (clean interface)
• Not use too many fonts (confusing to reader)
• Should not have overly bright or harsh colors (hurts
eyes)
16. Social and Ethical Issues
• Copyright
• Piracy
• Changing nature of work
18. The main theme
• The option topic is about how multimedia can be used to
communicate more effectively in the area:
• Education /Training
• Entertainment – Film and Television, Virtual Reality.
• Business – Take a virtual tour of a house.
• Emerging Technologies – LED TVs / 3D TV
» Digital TV
» IPhones
» Enhanced Reality
19. Vocabulary of Multimedia
• Enhance –to raise to a higher degree; intensify;
magnify: Video and Audio enhanced the
students learning
20. Synergy
• Synergy - the cooperative action of two or more elements for
greater effect than either alone.
• Example: “The effect of Multimedia is one of synergy. Video
and Text together create a more powerful
learning/entertainment/business impact than each shown by
themselves.”
21. Engage
• to occupy the attention or efforts of (a
person or persons): “The video, voice
narration and then interactive test
engaged the student…”
22. Interact
• Interact: To act on each other
• Interactive multimedia means the user and
program act upon the other. Both are
active processes.
23. Vector Graphics
Vector graphics use mathematical
Formulas to store graphic data
This line might be stored as A3:F3
Only 2 points need to be remembered
and stored on the HDD. When it is on
your screen however it must be
displayed as pixels
24. Vector Graphics
• These coordinates or “vectors” are known
as “primitives”. When stored on disk they
are referred to as primitives as they are
not formed yet.
26. Vector graphics
• As co-ordinates only need to be remembered, less
space is needed in storage.
• You can blow up pictures as large as required without
distortion or loss of info
• Because of this it is perfect for plan diagrams such as
blueprints, and technical specifications.
• It is the graphics used in Computer Aided Design or
(CAD)
• Vector graphics can easily be changed.
• If the program is called “*” Draw – It is a vector graphics
program. “*” Paint is bitmap
27.
28. Frame Buffer
• The frame buffer or Video Ram is an area of very fast memory that contains
the bitmap image of the current screen display
• Still pictures and movies must be displayed
Memory
Chip
29. Monitor
Frame buffer
mirrors exactly
the contents
of the frame Frame buffer or VRAM
contains the bitmap image
buffer with the details of each pixel
Each pixel and its
location needs to
be stored on your
HDD
30. The Frame Buffer and Image
size
BIT DEPTH Relationships Number of Colors
1 2 1
2
2 2 2
4
3 2 3 8
4 2 4 16
8 2 8 256
16 (high color) 2 16 65536
24 (true color) 2 24 16777216
31. The Frame buffer and Image size
• Resolution is measured by the number of
pixels per inch
Each Square is the same size but the
one with the most dots has higher
resolution
High Low
32. Jaggies or
Resolution & Bitmaps steps
Bitmaps distort and lose aspect ratio
(relationship between the width and the
height of an image ) unlike vector
graphics
If you enlarge a bitmap image too much it pixelates or has
jaggies
33. Anti-Aliasing
Anti-Aliasing is one of the most important techniques in
making graphics and text easy to read and pleasing to the eye on-screen is
anti-aliasing. Anti-aliasing is a cheaty way of getting round the low
72dpi resolution of the computer monitor and making objects appear as smooth
No Anti-Aliasing Anti-Aliasing
34. How it works
When the computer anti-aliases the line it works out how much of
each in-between pixel would be covered by the diagonal line and
draws that pixel as an intermediate shade between background
and foreground
35. Dithering
Dithering
Dithering is the process of “mixing” pixels of two colors to
create the illusion that a third color is present.
Full-color photographs may contain an almost infinite range of
color values. Dithering is the most common means of
reducing the color range of images down to the 256 (or
fewer) colors seen in 8-bit GIF images.
Example: An image with only black and white in the color
palette. By combining black and white pixels we can create
grey
37. How to calculate image size
800 pixels
Bit plane is set
At 24 bits
600 pixels
38. How to calculate the size
• Calculate the number of pixels and Multiply pixels by bit depth / bit plane
600 x 800 x 24 = 11 520 000 bits
• Calculate the number of bytes by dividing total bits by 8
800 pixels
11 520 000 / 8 = 1440 000 bytes
• Calculate the number of kilobytes by dividing by 1024 Bit plane set at 24 bits
600 pixels
1440 000 /1024 = 1406kb
Calculate the number of megabytes by dividing by 1024 since there are 1024 kb in a
megabyte
1406 / 1024 = 1. 44mb (rounded up to the nearest mb)
39. How to calculate the time needed to download or
upload the file USING A 56KB/S MODEM @ 200BITS
PER SECOND
• Formula is Size of file / total amount transferred per second
800 pixels
600 x 800 x 24 = 11 520 000 bits
11 520 000 / 200 bits per sec= 57600 seconds (Number of seconds to transfer)
Bit plane set at 24 bits
600 pixels
57600 / 60 seconds = 960 minutes
960 minutes / 60 minutes = 16 hours
40. Things to think about
Why is file size important when designing your webpage?
Should you choose 16 bit color or 24 bit color?
How can we reduce the amount of memory required for graphics?
Reduce bit plane (Dithering Does this)
Reduce resolution of graphic thereby reducing the number of pixels
41. Charged coupled
device (CCD)
converts light into
digital data or
converts digital
data into light
Video
Firewire
card
USB
Analogue Digital movie
capture file can now be
card edited
Capture digital data from digital video camera
If it is an analogue camera, a video capture card is needed to
sample the analogue data
42. Codec
Firewire card
USB
Codec
Analogue capture
Digital movie file can now
card
be edited
• Coder-decoder." A device or software application that converts analogue
video and audio signals into a digital format for transmission. Also converts
received digital signals back into analogue format.
43. Video Compression Example
Mpeg or Divx
• Frames are analysed and section of the
frames are analysed.
• If sections within frames are the same
such as a car coming down the road.
Repeated elements such as trees are
taken out. They are replaced upon
decompression.
44. Video Compression
Large file sizes of video means compression is often used.
2 types of compression are:
Lossy – Data is lost or shed for the sake of file size. This may be bit
depth ( number of colors) resolution, sound (stereo to mono)
Lossless – A type of compression that reduces data without shedding
information- Example: A word document is compressed. Spaces are
counted and then deleted. When uncompressed the spaces are put
back. The number common vowels may be counted and then
removed and then replaced by the program after decompression.
47. MICROPHONE
How to sample a sound or digitally convert it from
analogue to digital
ADC
000100100101101010101000
COMPUTER
MEMORY
000100100101101010101000 DAC
SPE
48. MICROPHONE
Sampling
ADC
01000
0001001001011010101
COMPUTER
MEMORY
DAC
01000
0001001001011010101
SPEAKER
Real World Analogue signals are converted to “0”s and “1s”
Not all the sound information is recorded. Only important samples along the analogue wave.
What is useful? –Only what humans actually hear
49. Digital Audio
The type, size of the file and quality of digital audio
depends on 3 elements:
1. Frequency (11 khz, 22 khz or 44 khz)
2. Mono / Stereo
3. Resolution: bit size of the samplings
50. Summary
In general, the following rules apply:
Frequency – The higher the rate, the better the sampling quality
Mono/Stereo – 1 (mono) or 2 (Stereo) channels create depth of sound but
needs more memory
Resolution – More bits sampled 8 vs 16 means greater accuracy
51. How to Calculate Digital File Sizing
Audio
video
Audio and video
52. Advantages of digitalised sound
Can be transported electronically or over a network (itunes)
Can be manipulated electronically I.e affects added
Can combine sounds and instruments to create a whole
orchestra
Can be copied easily
DRM can be applied
Can be indexed and databased for access
Can be easily stored on hard drive and other media
Can be compressed
53. M.I.D.I
Musical Instruments Digital Interface
MIDI (Musical Instrument Digital Interface, pronounced /
ˈmɪdi/) is an industry-standard protocol that enables
electronic musical instruments such as keyboard
controllers, computers, and other electronic equipment to
communicate, control, and synchronize with each other.
MIDI allows computers, synthesizers, MIDI controllers,
sound cards, samplers and drum machines to control one
another, and to exchange system data.
MIDI data files are very small and are often used as website
background music
54. How to calculate size of
uncompressed video
Calculate the size of a video file 10 seconds long at 5
frames per second, 50 pixels high and 50 pixels wide with a
bit depth of 8bits. Express in bytes
5 frames x 10 sec x (50 x50 x 8 ) / 8 = total
uncompressed size
56. Cell based animation
Cell based animation is when picture movement is drawn or
created a little bit different each time. When viewed in quick
succession it appears to move. This is the traditional method that
Disney used on transparent pieces of cellulose, hence “cells”
•Each picture is a frame or a cell
•Each one is drawn individually and requires memory storage
57. Cel Based Animation
Cont.
Notice the picture of the
sun. Each frame consists
of a background and a
“sprite/s” that move
58. Path Based Animation
Path based animation relies on the computer program to do most of the
work. The artist specifies the “path” for each moving object. Key points
are specified and then the program calculates what changes are needed
between points
Bang
Key point
Sprite
Key point Key point
59. Computer Fills the gaps between key
points of the animation
Bang
Key point
Sprites Key point
Key point
60. Path Based Animation cont.
• This use of key points in which the
computer generates everything that goes
between points is also known as
“tweening”.
61. Morphing
• Morphing is when 1 object changes to
another. Example: A man turning into a
lion
In this example, it is one person turning into another person
62. Warping
Warping should never be confused with Morphing. Warping is when the
original image is distorted, and twisted about
63. Digital Rights Management
• Technology designed to prevent the copying and distribution of
digital media.
Itunes. Prevents the moving of songs from one machine to the other.
Youtubes forthcoming digital fingerprinting.
Digital fingerprinting technology is when media is tagged so that if it is
uploaded, it is instantly recognised as copyrighted material and
automatically deleted.
Big pond movies – Media will only be playable for a given amount of
time.
64. How MP3s Work
• MP3 algorithms compress a digital sound
file to a much smaller size.
• Compression Algorithms are used to
reduce the size of the file using “lossy”
• An compression algorithm is a set of
instructions that process the sound file to
reduce it using a set of criteria.
65. How it works
• To make a good compression algorithm
for sound, a technique called perceptual
noise shaping is used. It's "perceptual"
partly because the MP3 format uses
characteristics of the human ear to design
the compression algorithm.
66. What the algorithm looks for to
leave out or emphasise
• certain sounds that the human ear
cannot hear.
• certain sounds that the human ear
hears much better than others.
• If there are two sounds playing
simultaneously, we hear the louder one
but cannot hear the softer one.
67. MP3
• certain parts of a song can be eliminated without
significantly hurting the quality of the song for
the listener.
• Compressing the rest of the song with well-
known compression techniques shrinks the song
considerably -- by a factor of 10 at least. When
you're done creating an MP3 file, what you have
is a "near-CD-quality" song. The MP3 version of
the song does not sound exactly the same as
the original CD song because some of it has
been removed.
68. How Film Compression works
• Files such as DivX, Mpeg and .AVI have been reduced
using the following methods:
• Reduce the number of frames per second.
• Reduce the sampling rate and size of the audio
• Removing from the video parts of the image that were
already shown.
Example: in a video where there is one person talking
and that this person is not moving. On the first frame the
image is shown complete, but on the second frame the
parts of the image that are identical to the first frame are
removed from the image. If only the mouth of the person
is moving, only the area around the mouth will be drawn
on the second frame.
69. Multimedia Types
• Text – includes words and numbers and special characters such as
#@$.
• Hypertext / Hyperlink – Clickable text that links to a URL (universal
Resource Locator) in the format of a www.domainname.com or file
location.
• Hypermedia- Is clickable media other than text. Example: we can
click on a photo or animated gif. It will link to a URL or file much the
same way as a hyperlink.
• Streaming video – Video which is sent over a network using UDP
protocols to be played on embedded video players on a browser.
• Whitespace – The area of a webpage left white. Too much clutter
confuses the user and inhibits communication. The correct amount
of whitespace will direct user focus.
70. New Technologies used to share
information via Multimedia
• RSS – Real Simple Syndication is a method by which
information is published to users to keep them updated.
A user elects to accept a RSS feed in their browser.
• Share features like Digg allow user ratings of web
content. Higher ratings result in a higher profile of the
content in the Internet community. (User interactivity)
• Twitter – information and opinion sharing forum that
played a prominent part in showing what happened in
Iran this year.
• Youtube – Video Streaming
71. Convergence
• Convergence describes the coming
together of technologies to form a new
one that is more powerful in its ability to
communicate.
• Example – Camera / Phone
» Camera /Phone/Computer
» Watch / GPS
» Video camera /GPS
