Multimedia is an interactive media and provides multiple ways to represent information to the user in a powerful manner. It provides interaction between users and digital information. It is a medium of communication. Some of the sectors where multimedia is used extensively are education, training, reference material, business presentations, advertising and documentaries.
The different elements of multimedia are
- Text: is an example of discrete media (existing continuously in space). Interesting use of text in multimedia has been hypertext, which allows links to be made between webpages by clicking on the hypertext. Text can be a powerful form of media when the right words are used. As well as the choice of words the following factors can affect the impact of the text: Whether it complements the other media, colour coordination, placement of the text for balance, and choice of font and layout for mood setting.
- Graphics/images: This involves perceiving both brightness and colour. Colour refers to how we perceive a narrow band of electromagnetic energy. An image is usually a 2D representation of the 3d life object. With bit-mapped graphics, a digital image is obtained through the digitisation process. The device captures the sample pixels which may be quantisation at a level of 2 bits (B&W image) to 24 bits (full colour). Spatial redundancy allows the pixels to be placed next to each other while the human eye perceives it as a solid image. Synthetic images are created in a different way, using vector graphics, which are described by formulae.
- Sound is the physical phenomenon caused by the vibration of material – the vibration cause fluctuation in the air, resulting in continuous waveforms, which are picked up by the human ear and perceived by the brain. The human can hear sounds within the 20 Hz to 20,000 Hz bandwidth range, therefore this is the range within which we digitise audio for multimedia.
- Speech: This has been increasingly significant in the use of speech-controlled applications – highly interactive. It is also very extremely useful in extending the multilingualism of an application.
- Music: Used in multimedia for mood-setting ambience, evoking emotions, giving context within multimedia (such as historically, geographically), etc.)
- Auditory special effects: These can be useful in enhancing the realism of a multimedia piece.
- Video: Digital video is an example of continuous media – it is a number of digital images played one after another. It exploits the use of temporal redundancy to minimise file size in that samples played next to each other will look like one continuous flow of media.
- There are three well know methods for transmitting video: Composite video, separate video, and component video. The latter is the highest quality and uses the most resources.
- Animation: It is a synthetically generated video. The highly sophisticated computer-generated imagery (CGI) is an example of the extent of software capabilities in generating animation. The ongoing challenge is how to create the effect of 3D – animation relies on being able to provide visual cues to create the effect.