Classification of Multimedia Applications
Until a few years ago, almost all multimedia applications were single-user (stand-alone multimedia). The first of these were specialized training, information or sales systems (CBT-Computer Based Training, POI-Points Of Information, POS-Points Of Sales). Then, with the increasing capabilities of personal computers and the introduction of CD-ROM as an inexpensive and practical distribution platform, the use of these applications became more generalized. Most of the applications of stand-alone multimedia are essentially not new. Similar systems have existed for a long time, but they were neither attractive nor effective enough to attract interest. With the addition of multimedia capabilities, they have been given a new dimension and their use has been generalised in many fields, but no new types of applications have actually been created. The attempt to categorise them results in their separation according to their field of application, since they are essentially all interactive applications that enable the user to handle large volumes and many types of information efficiently.
The area of networked multimedia is currently the branch of computer science that has attracted the most interest. Most importantly, the interest is coming from the research community as well as from the business community and the buying public. There is of course still a fluidity in the field, due to the technological barriers of the existing network infrastructure, as we saw in Chapter 8, and the lack of standards, but this has not prevented the first samples of a plethora of new applications from emerging. These applications fall into two main categories:
1. People-to-people multimedia applications
These applications are designed to facilitate communication between two or more people. The nature of this communication can take various forms: from personal social conversation to complex workgroup communication. Applications in this category can be further divided into the following subcategories:
Private versus business applications
Interpersonal applications versus group-oriented applications
real-time applications versus asynchronous applications
2. People-to-systems multimedia applications
These applications enable individual users to access information located on a remote system. Usually, the remote system is a multimedia information server.
Modern People-to-People Applications
Applications in which only two people take part (interpersonal applications)
Person-to-group applications, where the information originates from a single point and there are many recipients. In addition, these applications allow only one direction of communication. A typical example is seminars: the speaker's image is transmitted to many people who are far away from the room.
Group teleconferencing. This model allows bi-directional communication between two or more groups of people. Typically, communication is by means of speech (audio teleconferencing) or speech and video (audio-video teleconferencing). Another form of communication is working in a shared computer workspace (shared computer workspace). When different modes of communication are combined, it is called multimedia teleconferencing. More details about these applications will be given below.
Asynchronous People-to-People applications
Multimedia electronic mail. Its function is similar to conventional e-mail, except that the documents exchanged can contain formatted text, images, audio, video and links to external files.
Multimedia asynchronous computer conferencing. The term 'computer conferencing' refers to applications, which emerged in the 1980s, that allow asynchronous conferencing between individuals via bulletin boards. The addition of multimedia allows the sending of announcements containing other types of information than just text.
Interactive applications. This name is intended to emphasize the fact that the user has the first say in the communication and not the server. Consequently, the communication is done at the request of the user at the time he/she wishes. Usually, these applications are aimed at retrieving some information (information retrieval applications). In other cases, the user's interaction with the system is aimed at some kind of transaction (transaction oriented applications).
Distribution applications. This category has been discussed above. The difference here is that the information distributed is not intended to be communicated between individuals. Distribution may be limited to groups of individuals who have received some form of authorisation or to all those with the appropriate equipment.