This report is also available as an Acrobat file.
3. Range of equipment
One site to one site connections are typically called point to point connections. This reflects the number of sites connected rather than the number of people present at a site. Multipoint connections are also possible. However this is achieved by using a multipoint bridge and switching between sites can be carried out manually or can be voice activated (if you make a noise, you are seen). Multipoint bridges can be rented from British Telecom for the duration of a conference. They are prone to technical problems.
The Rollabout systems are used by corporate meetings when full screen, life-like intimacy is required. The codec, TV monitor, camera and microphone are all integrated into a single unit. Other audio-visual equipment can be used in conjunction with this equipment:
The choice of devices is dependent on the nature of the content of communication between the participants.
- Slide to video devices for displaying slides
- Micro-video systems for displaying microscopic images
- 3-D imaging devices for displaying real images
- PhotoCD presenters
- Video players
- Video Lecterns (visualiser) for documents and prepared presentations.
This form of equipment is more reliable than its DeskTop version. It is also more expensive. A recent setup at Heriot Watt University required investment of £25,000 at both ends of the connection. This type of equipment can be linked with stations supplied by other vendors. We have used this system with Norway, Holland, Australia and California on a regular basis. Although some functionality such as remote control of cameras is lost, the audio and visual connection is manageable. This equipment can be used if the focus of the conference is on the speakers and the materials being discussed are not in a computerized format. The range of audio- visual equipment means that little reworking of material is necessary.
DTVC is the technology which is bringing video conferencing back into focus. However, the frame rate and the tiny picture window makes standalone DTVC an uncompelling application. But when it is used in conjunction with other collaborative work software, such as whiteboards, shared screen and shared control, there is adequate functionality to entice users. This type of video conference is most useful when the documents and information to be exchanged are stored on the computer and of importance rather than the presenter. Information can be shared and discussed quickly over the network. Cutting out the time and cost of a courier.
There are a number of problems associated with this equipment:
The odd thing about DTVC is that it is not the video aspect that sells the system. This is simply incidental to file transfer and other co-operative working activities.
The best DTVC offers 15 fps (frames per second) or 16 fps. This is like watching a pixelated home video. Typical rates are even lower. This may never prove adequate if full screen live interaction is required.
- Crashes and bandwidth problems are common.
- Many systems do not support sound. This is handled via the telephone! This means that the sound and video image are not kept synchronised.
This equipment is not currently 100% reliable. The H261 standard is not well implemented. The equipment is cheaper than others, requiring an investment of around £5,000 per station. But both stations must be identical in terms of hardware and software, including versions.
Virtual Environments Visualisation