What is Videoconferencing?

Videoconferencing in its most basic form is the transmission of synchronized image (video) and speech (audio) back and forth between two or more physically separate locations, simulating an exchange as if the participants were in the same physical conversation. This is accomplished through the use of cameras (to capture and send video from your local endpoint), video displays (to display video received from remote endpoints), microphones (to capture and send audio from your local endpoint), and speakers (to play audio received from remote endpoints). Although there are many factors that serve to modify or increase the complexity of this basic definition, several of which are discussed in this cookbook, it is useful to keep the concept simple in the beginning when deciding why or how you may be able to use videoconferencing for yourself or your organization.

In understanding the role that videoconferencing could play, consider two general situations: 1) those where you are already able to communicate with someone who is not physically nearby, but you wish that communication could be richer, and 2) those where you wish to access or communicate to a location that may or may not be nearby but access to it is limited by situational or physical constraints.

Distance education often comes to mind when considering the first situation. However, it is worth reminding ourselves that videoconferencing can also be used to connect people with remote data, events, places and objects in real-time fashion. Several other types of communications can also be enhanced or extended. These include organizational and cross-organizational meetings, counseling, foreign language and cultural exchanges, and telecommuting. Communication is already occurring in each of these applications, but could be made more compelling, more effective, or less expensive through the use of videoconferencing. (Imagine a telephone call where you can see the speaker, or a television through which you can talk.)

For the second situation, the introduction of videoconferencing has enabled communication to restricted areas such as clean rooms, nuclear facilities, operating rooms, and the space shuttle. Videoconferencing enables us to teach students about the science and specialized equipment at hard to reach places such as remote laboratories, installations near volcanoes, remote lighthouses, telescopes, and microscopes. It has been used to observe wildlife in their natural habitat, to establish interactive surveillance and security and, combined with micro-instrumentation, to observe inside the human body. This side of videoconferencing may not come to mind as readily as the enhancement of simple communication but it can be quite powerful. Simply imagine situations where you might like to be a "fly on the wall" with the ability to interact if desired. To imagine even further, consider that videoconferencing can be point-to-point (between two endpoints), or multi-point (combining two or more endpoints into the same "conversation"). When you begin to combine diverse endpoints into one setting where audio and video from each can be shared in real-time, whole new levels of interaction are enabled and entirely new ideas for communication can result.

Once you determine that videoconferencing is for you, you need to be aware that there are a variety of technologies that provide this functionality and, overall, it is not at the point of being a "plug-and-play" technology. Videoconferencing actually began over a decade ago with the introduction of expensive group conferencing systems designed to send and receive compressed audio and video over network connections that could guarantee a dedicated rate of transmission and predictable service (i.e., point-to-point T1 or fractional T1 communication links, switched connections using ISDN, or ATM). Standards surrounding how the audio and video would be compressed, how the endpoints would communicate with each other (i.e., initiating/terminating calls, negotiating audio/video compatibility, indicating error conditions during a call), and how the video streams would travel over the network eventually evolved but systems were not fully interoperable at the start. Arguably the most popular and extensible early compressed videoconferencing was enabled via the ITU (International Telecommunications Union) standard called H.320 (videoconferencing over dedicated circuits - ISDN.) However, even with H.320, videoconferencing remained largely restricted to a) those that could afford the technology, network connections and meeting rooms, or b) those who were able to travel to a videoconference-enabled meeting location.

As time has gone on, the above restrictions have lessened. The technology for conducting videoconferencing has become less expensive, more flexible, and now includes options for desktop videoconferencing as well as group videoconferencing. More ubiquitous network types, particularly TCP/IP as used on the Internet, are commonly used to provide less expensive and more flexible connections. In conjunction with this, standards have emerged for supporting audio/videoconferencing over IP. The H.323 standard was first approved by the ITU in 1996, has evolved through several versions since then and is implemented in a wide variety of commercially available products. The IETF SIP Working Group is working to move the SIP protocol from proposed to draft standard and SIP-based videoconferencing tools are on the market today. Products in each of these standards are the primary focus of this cookbook today, however, information regarding other standards and means for videoconferencing is also included. In addition, the cookbook touches on many other factors required for a thorough understanding of videoconferencing. These include the importance of standards in general; videoconferencing needs assessment; application possibilities; basic equipment selection and use; advanced components and services; and new developments. It is both hoped and anticipated that the cookbook will help you to move from imagining what you might do with videoconferencing to a successful and effective videoconferencing deployment.