Multimedia in Computer Graphics

The word multimedia is made up of two separate words, multi meaning many, and media meaning ways through which information may be transmitted. Therefore, multimedia can be described as an integration of multiple media elements together to influence the given information so that it can be presented in an attractive and interactive manner. In simple words, multimedia means being able to communicate in more than one way. Traditionally, information was presented in a single medium only, be it newspaper or radio or television. With the development of computers, presenting data has taken an entirely new meaning. Multimedia is a computerized method of presenting information by combining audio, video, graphics, texts, and or animation components. For example, a multimedia database of musical instruments may allow a user not only to search and retrieve text about a particular instrument but also to see its pictures and play a piece of music. The advent of high-resolution screens and sound and video playback facilities for computers has resulted in the increased use of multimedia applications.

A typical multimedia application is characterized by some features which are as follows:

· Uses of digital technology

· Demands interaction from the user

· Integrates sound, images, text, and data into seamless applications.

As we know, multimedia is mainly concerned with the computer-controlled integration of text, graphics, drawings, still or moving images (video), animation and audio where every type of information can be represented, stored, transmitted, and processed digitally. The various elements that together constitute multimedia are as follows:

Text

The on-screen display of words, that is, text, is the base of most applications. Humankind developed text and symbols so that they could communicate. Writing helped human to remember things for a much longer period than what is possible with the help of memory (brain). Words and symbols in any form, spoken or written, are the most common means of communication. These days not only is the text capable of displaying information, but it has also gained interactivity; things like an electronic annotation, which assist in navigating through all the information presented on the Web by means of hypertext. A hypertext can be defined as an object in the text that allows the user to jump from one web page to another at a click of the mouse button. It acts like electronic footnotes and assists in navigating through all the information. Files may contain raw text or formatted text. For example, hypertext markup language (HTML), a program language source (C, Pascal) or rich text format (RTF)-a file format for text files that includes formatting like different font styles and typefaces and so on. The basic storage of text is 1 byte per character (text or format character). For other forms of data such as spreadsheet files, some may store format as text (with formatting), others may use binary encoding. Text can be written using various text editing and processing tools such as Word Processing Software such as Microsoft Word and Word Perfect where text file can be developed and later imported into the multimedia authoring tools to integrate with other media elements.

Graphics

It is a generic term used to describe the pictorial representation of data. When one talks about graphics, we generally tend to refer those pictorial representations that are created by the primitive objects such as lines, polygons, circles, curves, and arcs. For example, a picture of a cube can be drawn using lines and a pie chart can be drawn using lines and arcs. Images are still pictures that are represented as a bitmap (a grid of pixels) but, graphics are usually editable or revisable (unlike images). Generally, graphic input devices include keyboard, mouse, trackball or light pens.It is said that a picture is worth a thousand words, so by adding a graphic element into a text-based document can change the user’s perception towards the document. Integration of the graphics element into the application makes it more elegant and understandable. Growing technology has produced a wealth of graphics and visual imagery for a multimedia project. For the development of multimedia project, various images are captured from different sources like scanners, digital cameras, and through the Internet. Once the images are transformed into digitised form, they can be edited and modified using image editing software, namely, Adobe Photoshop, Corel Draw, and Freehand.

Audio

It means the sensation resulting from stimulation of the auditory mechanism by airwaves or vibrations. It is the vibration of air molecules in the atmosphere that can be sensed by the ear. It involves transmission of mechanical vibration by an elastic medium that is capable of being detected by the human ear. Computers and digital technology have changed the face of music industry. Today, digital music is used to produce special effects in televisions, films, in recording studios, and in games. Music and sound effects not only add interactivity with the user but also play with the user’s perception and emotions. Audio can also be used to provide a sense of place or mood as done to perfection in the game. Music is probably the most obvious form of sound. It can be used to set a mood, convey an idea, and even tell a story. Speech is also a perfect way for teaching users the pronunciation of words as done by the speech learning software. Non-speech sound effects can be used in the user interface to inform users about background events. For example, sound of the progress of a file download could be signalled by the sound of water pouring into a glass that gradually fills up. These kinds of background sounds have to be non-intrusive. Moreover, Sounds can be embedded into a web page and can be played.

Video

It refers to the moving picture accompanied by sound such as a movie on television. It is a medium that is as direct as print and catches more attention. It adds richness to content and enhances the user’s experience. It dramatises and gives impact to the multimedia application. Integrating video element in a multimedia application provides a great deal of information in a short time. If used in a planned and well-executed manner, it can make dramatic differences in the multimedia presentation. Digital video is useful in multimedia applications for showing real life objects, such as people talking or real life illustrations of concepts. Video places the highest performance demand on the computer memory and on the bandwidth if placed on the Internet. In terms of computers and Internet, the major problems with most videos are that their production quality is too low and they have a very large file size. To make video usable, video files need to be compressed in different file formats.

Animation

Itis the process of sequencing still images in rapid succession to give the effect of live motion. The sequence of images is shown one after the other very quickly so that the human eye and brain blend the images to produce the effect of motion. It is a powerful tool capable of communicating complex ideas. It is often much easier to show somebody how things work then to try to explain it. Animation is viable because of a natural phenomenon known as persistence of vision. An object seen by the human eye remains mapped on the eye’s retina for a short time interval after viewing. This makes it possible for a series of images that are changed very slightly and very rapidly, one after the other, to seemingly merge into a visual illusion of movement. In other words, if one just changes slightly the location or shape of an object rapidly enough, the eye will perceive the changes as motion. An animated sequence has to show a certain number of frames every second. For professional animation, one needs to have at least 30 frames per second.

In today’s challenging world, if the ideas of the presentation are not expressed in an effective manner then the presentation is a failure. One way of expressing imaginative ideas is by using graphics. Graphics can be presented in various modes which are described as follows:

· Background:It sets the tone and the theme of the presentation. It should be based on the type of information that is to be conveyed. For example, if the information is more text oriented, then simple background images should be used. In case, the information is to be conveyed to little kids then background should be more animated and colourful.

· Two-dimensional (2D) graphics:Usually, when one is looking at a computer screen, then he/she is at a two-dimensional image. The image spans from left to right and top to bottom but usually not in and out of the computer screen. A 2D image definition contains only information about how a scene appears from a particular point.

· Three-dimensional (3D) graphics:A 3D image contains information about the scene in three dimensions (x, y, and z coordinates). However, this 3D data cannot be viewed directly. In order to view it, first the 3D data must be converted into a 2D image by the computer using a process known as rendering. The rendering process takes as input the 3D scene and the location and attributes of a camera and produces as output the 2D image that the camera sees from that particular point in space. The process is done by mathematically projecting a 3D scene onto a 2D surface. In photography, this is done by the camera lens, but in computer graphics, this is done by solving mathematical equations. In both cases, the result is a 2D image that has been generated from a 3D scene.

· Charts and graphs:In business and training-related multimedia projects, charts and graphs are the most appropriate forms of graphics used for presenting facts and figures related information.

· Flowcharts: The use of the flowcharts expresses the systematic order of an event. They are developed mainly to break the complex problem-solving steps into smaller, less complicated steps so that developing logic becomes easier. They are also used for representing 2D graphics.

Source by Neeraj Kr Sharma