User`s guide

2 Background Information
2.1 Uses for Videoconferencing
Videoconferencing allows users who are remote from each other to work and play cooperatively. The
foundations of videoconferencing are in video telephony. The first video telephone call was made in
1927 (Kraut 1994), but since then, no video telephone product has been successful. Recent devel-
opments have had more success but the telephone is still the main form of remote communication.
Videoconferencing systems need to be carefully adapted to human needs.
The technology for computer-based videoconferencing has only been available for about ten years
(Fish 1994), and commercial systems have only been viable for approximately five years (PictureTel
2000, First Virtual 2000, VTEL 2000). The systems have grown rapidly from being used mainly in
research to being off-the-shelf products.
Videoconferencing systems can be classified into two types: (1), narrow-angle systems, in which
each person has their own camera, and (2), wide-angle systems, in which a number of people share
a single camera. These systems will be referred to as “personal” and “group” videoconferencing
systems respectively.
Personal systems may be used as “video telephones”, or users may see a number of others simul-
taneously, usually in separate windows, although each user will have their own camera. Sound is
usually monophonic. Sometimes these systems are referred to as desktop videoconferencing systems
(Kraut 1994).
Group systems are most commonly found in corporate board rooms or conference rooms. The
display is usually a large screen television or projector. Sound is usually stereo, and is audible
throughout the entire room.
The VideoWindow (Fish 1990) and Cruiser (Fish 1993) systems are good examples of each of the
two types of videoconferencing systems — group and personal, respectively. The group system is
designed for conversations between two or more people, while the personal system is designed to be
used on a user’s personal computer. Each one has different problems associated with it, as will be
discussed later.
Videoconferencing systems consist either of a view of a group of people or a single-person view,
and, as mentioned above, each is suited to different situations. There are uses for both hardware-
and software-based videoconferencing systems. Hardware systems are better suited to conferences
between groups, or where the system will be running for long durations. Software systems are better
suited for communication between two people, where conferences are short, or for streaming to a
number of people in separate locations.
IP videoconferencing has some advantages over hardware-based videoconferencing, such as lower
cost, use of existing network infrastructure, and the ability for users to use videoconferencing sys-
tems from their personal computers. However, hardware systems offer higher frame rates, better
picture quality, and typically use a dedicated link so bandwidth isn’t shared with LANs and Internet
connections.
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