Office and Internet Applications: Multimedia Presentation of Information
1. Multimedia Elements
Multimedia is the use of several different media to convey information. Multimedia
elements
comprise
text,
video,
audio,
animation
and
(graphics.http://www.w3schools.com/media/media_intro.asp)
1.1 Text
Text is a fundamental element used to convey information. It can be enhanced by a
variety of textual effects to emphasize and clarify information, e.g., font size, color,
style or special effects, such as shadow, blinking, bouncing or fading. However,
blinking and bouncing are not recommended by some experts as they may confuse
viewers? attention.
1.2 Graphics
A graphic is a digital representation of non-text information, such as a drawing,
charts or photographs. There are two common graphics types, Vector graphics and
Bitmap graphics. (http://www.rsna.org/Technology/internet5-1.cfm)
1.2.1 Vector Graphics & Bitmap Graphics
Vector Graphics
Vector graphics describe image by mathematical formulas that define all the shapes in
the image. Storage space requirement of a vector graphics depends on the number and
complexity of objects. It is used in drawing software, charting software and
computer-aided design. Programs such as Corel Draw, and all CAD programs use
vector graphics. Their images need to be scaled up or down while retaining all of the
image detail. In order to print CAD drawings you need a printer or plotter capable of
understanding vector graphics
Since vector graphics stores the formulas describing the image, vector drawing can be
scaled up or down without any loss in quality.
Bitmap Graphics
Bitmap graphics describe images as matrix of dots or pixels (picture element), the
smallest element that display or print hardware and software can manipulate. Its
operation is like a mosaic, using different dots (pixels) to depict a picture. Unlike
vector graphics, when a bitmap graph is scaled up too much, the quality of the graph
decreases as there is no information to fill in the expanded space. Digital cameras and
scanners use CCD or CMOS image sensors made up of individual pixel sensors to
capture an image.
The file size of a bitmap file varies a lot, depending on several factors such as
resolution and color depth.
Resolution
There are two different kinds of resolutions used in computer. The resolution of the
screen / monitor is the number of pixels that can be displayed in the monitor.
Traditionally the typical resolution settings of monitor are:
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640 x 480 pixels
800 x 600 pixels
1024 x 768 pixels
1280 x 1024 pixels
The higher the number, the more details of a picture can be shown on the monitor.
Scanner and printer use dpi (dot per inch) to represent the resolution. For an
acceptable print quality, the resolution of the image should be at least 150 dpi.
Color Depth
Resolution refers to the fineness of the image. However, it does not deal with the
number of colors that image can represent. Color depth is used to deal with this issue.
Color depth describes the number of bits used to represent the color of a single pixel
in a bitmap image. Higher color depth gives a broader range of distinct colors.
The number of available colors for each pixel depends on the number of bits used to
store the color information. For examples,
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
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

bit color (21 = 2 colors) monochrome, often black and white
2-bit color (22 = 4 colors)
4-bit color (24 = 16 colors)
8-bit color (28 = 256 colors)
16-bit color (216 = 65,536 colors) (high color)
24-bit color (224 = 16,777,216 colors) (True color)
The printers and scanners commonly found in the market nowadays use 24 or 48 bits
to store the color it can represent in one single pixel. In general an image presented in
high or true color is compatible to traditional photo quality.
Once the resolution and the color depth of an image is known, the file size of that
image can be calculated as:
File size = resolution x color depth / 8 bytes
If the file size is too large, you can compress the image in some cases.
1.2.2 Graphics File Format
There are several graphic file formats used commonly such as bmp, jpg, gif, png, tif,
etc. They can be categorized into two major classes:

Lossless compression - All image color and detail information is retained as
the image is compressed. Lossless compression retains image sharpness and
clarity. Gif, png, and tif are lossless images.

Lossy compression - Image color or image detail information is reduced to
compress the image. Lossy compression makes much smaller image files than
lossless. Jpg is lossy image.
GIF File (Graphics Interchange Format)
It is commonly used image format for Internet graphics. It can store only to 256
different colors, including "transparent"
colors such as icons, but are less suitable for photo-realistic images due to the limited
number of colors it can show.
JPG/JPEG File (Joint Photographic Experts Group)
It is commonly used in general applications and internet. It is a lossy compression. It
is suitable for displaying photo-realistic images because can contain up to 16 million
colors.
BMP File (Basic Multilingual Plane)
It is not a very efficient format because it is not compressed, which makes it
unsuitable for online use. It is a loss less format. In the past it was used to present both
graphics and photo. However, because of its huge file size, it was gradually faded out
when internet is getting more popular as it was not convenient to send pictures with
large file size, especially when the internet connection speed was not fast.
PNG File (Portable Network Graphics)
It uses a lossless compression method like GIF. It has two formats, PNG-8, which
supports up to 256 colors, and PNG-24 which supports millions of colors. It has a
better compression than GIF, meaning smaller files, without losing information as in
JPEG
TIFF File (Tagged Image File Format)
It was originally developed for scanned images, providing high-quality graphics. It is
the most universal format and is compatible with a wide range of software
applications and can be used across platforms such as Macintosh, Windows, and
UNIX. Its format is complex, so files are generally much larger than GIF or JPEG
files.
Here is a summary table comparing different file formats:
bmp
tif
jpg
gif
png
Lossless
Lossy
Lossless
Lossless
24-bit
24-bit
8-bit
24-bit
Transparency No
No
No
Yes
Yes
No
No
No
Yes
No
Compression Lossless
Color depth
Animation
24-bit
1.2.3 File Conversion
Most output devices, including dot-matrix printers, laser printers, and display
monitors, are bitmap devices. As a result, vector objects should be converted into
bitmaps before being output. Moreover, except SVG (Scalable Vector Graphics),
vector graphics cannot be shown in internet browser without appropriate plug-in.
Therefore for convenience it is better to convert vector graphics into bitmap graphics.
Converting Vector Graphics into Bitmap Graphics
It is not difficult to convert a vector graphic into bitmap graphic. In a vector graphics
program, open the file and retrieve the vector graphic file, then use the ?SAVE AS?
Function to convert the vector graphic into a bitmap one, such as gif, jpg or png.
1.3 Audio
Sound can be recorded in different formats.
1.3.1 MIDI (Musical Instrument Digital Interface)
A standard protocol for the interchange of musical information between musical
instruments, synthesizers and computers. MIDI was developed to allow the keyboard
of one synthesizer to play notes generated by another.
MIDI does not record analog sound waves like a tape recorder. MIDI encodes
keyboard functions, which includes the start of a note, its pitch, length, volume and
musical attributes, such as vibrato. As a result, MIDI files take up considerably less
space than digitized sound files. (http://www.answers.com/MIDI)
The MIDI format is supported by many different software systems over a large range
of platforms. MIDI files are supported by all the most popular Internet browsers.
Sounds stored in the MIDI format have the extension .mid or .midi.
http://www.w3schools.com/media/media_soundformats.asp
1.3.2 Digital Audio
Traditional audio devices are analog, because they handle sound waves in an
analogous form.
Audio is processed in a computer by converting the analog signal into a digital code
using various techniques, such as PCM. Digital audio are the sound waves that have
been digitized and stored in the computer. Common digital audio formats are music
CDs, MP3 and WAV.
The WAVE (waveform) format, which is developed by IBM and Microsoft, is
uncompressed digital samples derived from the analog source. It is supported by all
computers running Windows, and by all the most popular web browsers. Sounds
stored in the WAVE format have the extension .wav. The WAV format is widely used
as the audio medium for professional recording and editing.
MP3 is a popular digital audio encoding and lossy compression format. It was
designed to greatly reduce the amount of data (10:1 compression is common) required
to represent audio.
1.4 Animation
http://www.livemotioncentral.com/tutorials/lm1/0006/
Animation describes moving diagrams or cartoons that are made up of a sequence of
images displayed one after the other. The two most popular animation formats on the
Web are animated GIFs and Flash.
1.4.1 Animated GIF
http://www.answers.com/animated%20GIF
A moving picture in GIF format, which is made up of a series of frames. When
displayed, they provide an animated sequence that cycles over and over without
stopping. Although popular on the Web, animated GIFs are larger than single-frame
GIFs and take longer to download.
1.4.2 Flash
An animated graphics technology and format from Macromedia. Flash supports
vector graphics images, which scale with the application window as it is resized.
Animation is planned out using one or more sequential timelines in which actions and
interactions are defined.
Flash is popular on the Web for instructional sequences as well as animations of all
kind. Flash is an interactive format and its vector images take up much less space than
GIF's bitmapped images.
1.5 Video
A video is the technology of processing electronic signals for representing moving
pictures. It consists of images and sound.
It commonly refers to related types of carrier formats ?which can either be digital or
analog. Though television broadcasting and home movies have long been the
traditional application of video technology, with the Internet has come the rise of
compressed video file formats to syndicate video files to a global audience. Digital
video camera and Web cam can be used to create digital video while Video Cassette
Analogue camcorder to produce analogue video.
1.5.1 AVI File (Audio Video Interleave)
A Windows multimedia video format from Microsoft. AVI files are limited to 320 x
240 resolution, and 30 frames per second, neither of which is adequate for full-screen,
full-motion video. This format is supported by all computers running Windows, and
by all the most popular web browsers.
1.5.2 MPEG File (Moving Picture Experts Group)
Any of a set of standards established for the compression of digital video and audio
data. The MPEG codecs (compressor and decompressor) use lossy data compression
using transform codecs.
MPEG formats include:
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MPEG-1 for Video CDs
MPEG-2 for DVD, Digital TV
MPEG-4 for transmitting video and images over a narrower bandwidth.
1.5.3 Video Streaming
Video Streaming is the process of transferring data in a continuous and even flow. It
allows users to access and use a file while it is transmitting. It is important because
most users do not have fast enough Internet connections to download a large
multimedia file quickly. It enables you to listen to the sound (the data) as it downloads
to your computer.
The popular Streaming media programs are Windows Media Player and RealPlayer.
Reference:
http://www.w3schools.com/media/default.asp
http://www.answers.com/multimedia