Multimedia System_BSC

Multimedia: Multimedia is content that uses a combination of different content form such as text, audio, images, animation, video and interactive content. The multimedia may be combined with movie, presentation, interactivity, graphics or animation to give some information which can be stored, transmitted and processed digitally.

Multimedia application can be divided into 3 categories

Information system: It is used to provide information for one or several users. The requested information is stored in database or in media archives. Example weather information systems, electronic publishing.

Remote representation: A user takes part in or monitors events at remote location. Example distance conference, virtual reality, distances learning.

Entertainment: The major application area of multimedia is strongly oriented towards audio and video data. Example digital television, video on demand, distributed games.

Characteristics of Multimedia system: Multimedia system has 4 basic characteristic

Computer controlled: It is a computer controlled because we need to use computer for producing (using image editor, sound and video editor), storing (provide large storage capacity to store information), transmitting (used to transmit stored multimedia through network), presenting (by using display device (monitor), or speaker for sound generation) information to the end users.

Integrated: All multimedia components such as text, graphics, audio, video must be integrated with each other.

Digitally represented: Digitization is the process of transforming analog signal into digital data. All information such as text, audio, image etc must be stored digital in computer so that the content can be display during presentation.

Interactivity: Every multimedia system must be easy to use. It must be able to set or select time at which presentation starts, order of information and speed of presentation. User must be able to modify information and this modification must be recorded.

Elements or components of Multimedia: The component of multimedia include text, audio, video, image and animation

Text: Text is the basic element of multimedia. Text is combination of alphabets symbols, digits, punctuation etc. In a multimedia application, other media or screen can be linked through the use of text. This is what you call Hypertext.

Data (textual or digits) is easy to represent using general character but difficult to represent in computer system, so binary encoding is used for storing and processing. Commonly used encoding are 1) IRA or ASCII and 2) UNICODE

1) IRA (International Reference Alphabet) or ASCII (American Standard Code for Information Interchange) code, each character is represented by 8-bit, and 8th bit is used for parity bit( odd or even parity). It is useful for error detection. It represent well for English character not for National character.

2) Unicode is represented by 16 bits for each character. It is used to represent national character also.

Suppose that a page has following estimates (6 by 9 inch page size, 3 lines /inch and common typeface 10 chars/inch). What is the size of page using IRA encoding if it is full characters, what will be the size if UNICODE is used?

                        Width of paper = 6 inch

                        Height of paper = 9 inch

Lines/inch = 3

Character /inch=10

Number of line in the paper=9x3=27

Character in a line=10x6=60

Total number of character in the page=27x60=1620

IRA encoding is used, 8-bit are used to represent a character

Size of the page=1620x8= 12960 bits

=12960/8= 1620 byte

=1620/1024=1.58 KB

If UNICODE is used, 16 bits are required to represent a character

Size of the page=1620x16= 25920 bits

=25920/8 = 3240 byte

=3240/1024=3.16 KB

Graphics (Image):  A picture is a worth of thousand words. An image, figure, picture or drawing can consider as graphics. Graphics represent still image and defined as static representation. Extensions are jpeg, gif, bmp, png, jpg etc. Common graphic software program are photoshop, paint.Net etc

For example Photoshop of an employee with his/her name, sex, age, address etc from a company's  database of employee's make the employee information much more effective.

There are two types of graphics used: bitmaps (paint graphics) and vector (draw graphics).

Vector Graphics: An image is represented as a collection of straight and curved line segments. We cannot achieve photographic quality image by using vector graphics. CRD, PS uses vector graphics.

Raster Graphics: Raster graphics image is a dot matrix data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium. Raster images are stored in image files with varying formats.

 If each pixel is represented by single bit it is black and white image.

If more than 1 bit is used, gray scale image.

If 24 bit color is used, 8 bit represent each color red, green and blue (RGB).

BMP (Windows bitmap), jpeg (Joint Photographic Experts Group, gif (Graphics Interchange Format) use raster graphics.

Size of raster (bitmap) is determined by

Resolution: Number of pixel in row by number of pixel in column of a display screen is called resolution. Example 800x600 resolutions means 800 pixel in row and 600 pixels in column. Higher the resolution better will be image quality but larger will be size.

Color depth: Number of bits used to represent color a pixel is called color depth. 24-bit color means 24 bits are used to represent a single color. Higher the color bit better will be image quality but larger will be size.

Example: Assume that we have black and white monitor having resolution 800 x 600. What will be the size of an image without compression? What will be the size if 32-bit color monitor is used?

Total number of pixel = 800 x 600 = 480000

Since we are using black and white monitor, a pixel is represented by 1 bit

Thus, size of image = 480000bits

= 480000 / 8 = 60000 byte

= 60000/1024 =58.595 KB

If 32 bit color monitor is used to display the image, Thus

Size of the image=480000x32 bits

=15360000/8

1920000/1024

=1875KB

=1.83MB

Audio: A multimedia application may require the use of speech, music and sound effects. These are called audio or the sound element. There are two basic types of audio or sound: analog and digital audio. Applications of audio service are telephone communication, telemarketing, voicemail, audio teleconferencing, radio etc. Audio format include MP3, WMA, Wave, MIDI and RealAudio. Soundcard, headphone, speaker, audio mixer, and microphones are used for generating audio or sound.

Sound wave are characterized by

Amplitude: Maximum height attained by sound wave. It determines loudness of the sound.

Frequency: Number of cycle per second. It is determines pitch of sound and is measured in hertz.

Bandwidth: Range of frequency in a sound wave. It is measured in hertz.

What will be the size of digital audio of telephone voice of 5 minute if 6000 samples per second taken and each sample is represented by 8 bit.

No. of sample per second = 6000

Size of each sample = 8 bit

Size of digital audio of 1 sec = 6000 X 8 bits

= 48000 bits

Thus, size of audio of 5 min = 48000 X 5 x 60

                        = 1400000

                        =1400000 / 8 = 175.78

                        = 175.78 / 1024

                        = 1.716 MB

                       

Video: Video is the sequence of images over time. Video clips can be combined with audio, text, graphics. Video conferencing, television, multimedia, CCTV etc are application of video communication, Common digital video formats include flash, Mpeg, AVI, WMV and QuickTime etc.

We have 32-bit monitor having resolution 800 x 600. What will be the size of a video of length 10 minute without compression? Assume refresh rate is 40.

Total no. of pixel = 800 x 600            = 480000

We are using 32-bit monitor, pixel is represented by 32 bit

Thus, Size of single image = 480000x32 bit  = 15360000 bit

=15360000/8=1920000

=1920000/1024

1875KB

Since refresh rate = 40

Thus, size of video of 10 minute =1875x10x60x40 = 45000000 KB

45000000/1024 = 43945.31 MB

43945.31/1024= 42.9GB

Animation: Animation is the displaying of image in a sequence to create an effect a visual change or motion similar to a movie (video).Image generation tools such as digital camera, scanner and video generation tools such as digital video camera, videocassette Recorder (VCR), Digital Versatile Disk (DVD) are the powerful tool for generating images and videos for animation. Common tools for creating animation are Adobe flash. Example Cartoons on television.

Multimedia System: Multimedia system is a system capable of processing multimedia data and application. Components required for multimedia system are

·       Capture device: video camera, video recorder, keyboard, mouse

·       Storage Device: Hard disk, CD/DVD ROM, Jazz/Zip drivers etc

·       Communication Networks: Ethernet, token Ring, FDDI, ATM, Intranets, Internets

·       Computer Systems:  Multimedia desktop , workstation, MPEG/VIDEO/DSP hardware

·       Display Devices: color printers, HDTV,

·       System Software:  Multimedia is created and display using range of software application. Software tools can be divided into two groups 1) System software- It is used to established communication between system resources and applications.  2) Authoring Tools - It is used to combine text, graphics, animation, audio and video. Example Creation of interactive online quizzes.

Multimedia Features:

ü  Very high processing power is needed to deal with large data processing and real time delivery of media.

ü  Multimedia capable File system is needed to deliver real time media. Example audio/video streaming

ü  Data Representation that support multimedia that should allow for compression/decompression in real time.

ü  Efficient and High I/O needs to be effective and fast. It allows for real-time recording as well as playback of data.

ü  Special Operating System allows to access file system and process data efficiently and quick. Support direct transfer to disk, real time scheduling, fast interrupt processing I/O streaming etc.

ü  Storage and Memory should have large storage unit and large memory. Caches are also required.

ü  Network Support such as client server system and distributed system.

ü  Software Tools which are user friendly tools needed to handle media, design and develop application delivered media

Application of Multimedia: Multimedia finds its application in various areas including

1.     Entertainment and fine arts: multimedia is heavily used in the entertainment industry, especially to develop special effects in movies and animations. Multimedia games are a popular pastime and are software programs available either as CD-ROMs or online. Multimedia applications that allow users to actively participate instead of just sitting by as passive recipients of information are called Interactive Multimedia. In the Arts there are multimedia artists whose minds are able to blend techniques using different media that in some way incorporates interaction with the viewer.

2.     Advertisement. It helps in advertisement of product for business organization. The concept of e-commerce is not only needed online purchasing, but advertise products amongst inter users.

3.     Education: Multimedia is used to produce computer based training courses (CBTs) and reference books like encyclopedia. CBT lets the user go through a series of presentations, text about a particular topic, and associated illustrations in various information formats. A large number of university also provide also provide online degree or distance mode of education courses for the higher education. Universities provide study material online, students reads it in their free time by using computer, give examination and receive university degree from their own locations.

4.     Journalism: Freelance journalists can make use of different new media to produce multimedia pieces for their news stories. It engages global audiences and tells stories with technology, which develops new communication techniques for both media producers and consumers.

5.     Multimedia reporters who are mobile (usually driving around a community with cameras, audio and video recorders, and laptop computers) are often referred to as Mojos, from mobile journalist.

6.     Engineering Software may use multimedia in Computer Simulations for anything from entertainment to training such as military or industrial training.

7.     Industry:  Multimedia is used as a way to help present information to shareholders, superiors and coworkers. Multimedia is also helpful for providing employee training, advertising and selling products all over the world via virtually unlimited web-based technology.

8.     Mathematical and scientific research: In mathematical and scientific research, multimedia is mainly used for modeling and simulation. For example, a scientist can look at a molecular model of a particular substance and manipulate it to arrive at a new substance.

9.     Medicine: In medicine, doctors can get trained by looking at a virtual surgery or they can simulate how the human body is affected by diseases spread by viruses and bacteria and then develop techniques to prevent it. Multimedia applications such as virtual surgeries also help doctors to get practical training.

10.  Document imaging: It is a technique that takes hard copy of an image/document and converts it into a digital format (for example, scanners).

11.  Disabilities: Media allows those with disabilities to gain qualifications in the multimedia field so they can pursue careers that give them access to a wide array of powerful communication forms.

12.  Presentation: It is a strong medium of presentation of graphs, reports and any other materials. The business organization, training centers, learning all depend on effective presentation. There are tools and techniques are developing to developed presentation kits.

13.  Virtual reality and Simulations: Flight simulation are used to train pilots, the external effect such as changing weather, required high resolution image and ability to control different aspects of the system.

14.  Training: The school, colleges, business organization etc use video clips, slideshows to trained manpower.

15.  Information Provision: Multimedia encyclopedia is an example of a multimedia system used to provide information. It displays information using text, color, audio and video or animation.