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Videoconferencing at UVa

Implementation Example

Videoconferencing for small groups includes connecting conference rooms, seminar rooms, or other small groups that are geographically separate. This document describes one videoconference-equipped conference room as an example for departments whose members wish to install their own facility.

Table of Contents

At U.Va. the Information Technology Servicess department has major offices in several different buildings. A conference room at each of the sites has been equipped with a videoconferencing system that provides full-screen video at a fast frame rate over a TCP/IP network connection. A similar system installed in the Curry School of Education is being used to connect seminars at U.Va. with seminars at other institutions.

Choices can be made within some of the categories that will affect the flexibility and overall cost of the system.

VCON Hardware/Software

ITS chose the VCON Armada Escort 25 Pro system after evaluating several other videoconferencing solutions. The VCON system provides up to 768 kilobits per second of bandwidth. This enables the system to achieve a 30 frames-per-second transmission rate with full-screen video.

It is a kit consisting of a video capture board, software which provides a graphical user interface to the audio, video, and data sharing features, a small Philips camera with integrated microphone, and a handset for single-user audio. The board provides a modified S-video connection, which is used by the Philips camera, and a composite video connection. Speakers may also be connected to the board. The kit costs around $700, and provides a low-cost means of acquiring the fundamentals of H.323 videoconferencing. Addition of a higher-quality camera and a Polycom SoundStation (conference phone and converter) further enhance the performance. A headset can also be used (see below).

Windows PC

An ordinary, recent-vintage Dell desktop PC is installed in the conference room. A Gyration wireless RF keyboard/mouse allows for flexible use anywhere in the room.

Network

A standard TCP/IP connection like those found in offices, dorm rooms, and other locations in the University is sufficient for use with any videoconferencing client since it is a dedicated network connection. This connection is not shared with other users in the building. The network traffic is carried directly to the building switch and onto the backbone of the network.

The network at the other site

It is not enough that your network and U.Va.'s network have sufficient and reliable bandwidth. The site at the other end of the videoconference must also have adequate and reliable bandwidth, and all the networks between your two sites must have adequate and reliable bandwidth. U.Va. is connected to Internet II, a network with larger bandwidth and less traffic than the networks that make up the commercial Internet (MCI, Sprintlink, Alter-Net, and other commercial entities combine to form this network). If both ends of the videoconference are Internet II members, the network traffic between them will travel completely within the Internet II network. This provides both a high-bandwidth and a reliable connection. The current members of Internet II are listed on the Internet II web site. In addition, U.Va. is a member of Network Virginia, which provides a high-bandwidth connection to other sites within Virginia.

Video Camera

Transmitted video frames are only as good as the signal provided by the camera. Investing in a good camera is essential.

Videoconference appliances generally have a good built-in camera. Software-based systems such as Polycom PVX depend on a USB camera. Small, cheap "webcams" (in the $30 and less range) are usually not of high-enough quality for a good videoconference experience. Webcams in the $100-range are good quality, and usually include a mic.

Audio Equipment

Paradoxically, audio is harder to handle correctly than video. The problem is that an open microphone in a room with loudspeakers will pick up the voice of the person at the remote site, and echo it back to the remote site. The person who is speaking hears his/her own voice, delayed by several hundred milliseconds. This delayed auditory feedback is more than just annoying. At the right delay for many people, it can actually induce dysfluency. You may have noticed that radio and recording studios use headphones when a person needs to listen to an audio signal that must not be picked up by the microphone. This method does not work well in videoconferencing sessions with groups.

The solution is to incorporate the microphone and speakers into the same unit so that circuitry can be employed which prevents interaction between the two signals. For small groups, a Polycom SoundPoint PC audio unit can be used. The microphone pickup is limited, however -- it is very directional, and the user must be seated close to the unit.

A full-duplex conference telephone is a good backup to have available in a room designed for H.323 videoconferencing, and can solve the audio problem. If the network audio has "technical difficulties" or should there be a problem with the video or network, a speaker phone provides a channel between the sites while the problem is fixed (for instance, should the PC need to be rebooted in the middle of a conference or seminar).

If the conferencer wishes to use the VCON unit with a headset, a "line level" input must be used. Most PC headsets have a mini-phono connector, while a line level input needs both an RCA connector and a different type of signal. Fortunately, such headsets with signal converters can be acquired.

Multipoint Control Unit (MCU)

If more than two sites wish to collaborate, or if sites have different brands of videoconferencing software that refuse to interoperate, a "multipoint control unit" can provide an intermediate link. It can connect a set of H.323 clients to a common conference. It mixes the sound from all sessions and sends the combined conversations to all sites. Each site can choose which remote site to view, and can switch among the other participants during the conference.

The University of Virginia provides two such MCUs.

The Room

If you obtain a computer with an oversize monitor, you must carefully choose a cart or cabinet to house it. In addition to being sturdy (the monitor is heavy), wide, and deep (the monitor footprint is large), the height of the monitor should be low enough that persons who are seated in the room do not have to crane their necks to watch the screen.

A glossy conference table looks nice to persons in the room, but when viewed from a remote site, the gloss reflects everyone sitting around it, and any objects sitting on it. This makes the image visually confusing. A light-colored, non-glossy surface will reflect diffuse light onto those seated around it, improving the video image.

The camera needs to be placed either directly above or below the video screen. Conference participants will look at the video image of the other site, so having the camera in line with the screen will enhance the perception that the groups are looking at each other while interacting.

Dimmable ceiling lights and good blinds on any windows are needed. Sunlight streaming in a window is hard to correct in camera settings. Diffuse sunlight at some times of day (and season) helps to brighten the room, but it can sometimes be far too bright. A good set of blinds provides the flexibility to either use the sunlight or block it. If tracklights are installed, brightness is good, but don't get fixtures that radiate a lot of heat into the room. You don't want to roast the conference participants.

If a single person or very small group will be "speaking" to remote sites in a panel or keynote situation, a light-colored backdrop can be used to hide elements of the room that clutter the image (such as corners, moldings, windows, etc.). Portable studio lights can be used to brighten the image and give a more professional appearance. Attention to these details is more important when the focus is on a single or small group of presenters than in more impromptu conference or seminar situations.

Electronic Whiteboard and Projector

Combination of an electronic whiteboard and projector with an H.323 videoconferencing system enhances collaboration between sites. Although a software whiteboard is a component of most H.323 systems, an electronic whiteboard allows a person to use a pointing device directly on the surface to either activate buttons or annotate with a "highlighter". Many presenters find this to be much more comfortable.

An important consideration when installing a whiteboard/projector to be used in conjunction with H.323 videoconferencing is to not build a system where the H.323 session is projected on the whiteboard only, thus forcing users to either view remote participants or the application on the whiteboard. Although using the projection system to view the videoconference is an excellent option when the whiteboard is not going to be used, provision of a monitor and a switch box (to choose between monitor or projector) gives the most flexibility.

Page Updated: 2012-02-16