 |
 |
 |
 |
 |
 |
 | |||
 |
 |
 |
 |
 |
|
|
|||
Contents
Home
In business, multimedia technology, is expected to push a more versatile desk-top environment. Videomail could provide an easier to use replacement for text base e-mail, and databases could take the form of visual encyclopaedias. In the UK Telecom operators have emerged as the most active players in the multimedia market. A partnership has been formed between BT, Videologic and Motorola with the aim of developing multimedia semiconductors. Videologic will contribute VLSI silicon design while BT develop the Motorola Multimedia Communications chipset. The initial focus being on the development of the market for BT’s PC integrated videophone. BT are working this technology in conjunction with their video on demand work, offering a dial up video service over existing phone lines.
Currently there are four platforms that offer full desk-top video.Appendix 2 has descriptions of a selection of PC integrated videoconferencing products. This is simply to give an idea of the large range of systems currently available, but cannot possibly be all encompassing. Prices are listed when known, this also gives an indication of the range of possibilities. One of the most important price determinants is the interoperability, or compliance with standards. A system fully compliant with CCITT standards will cost several hundreds, or even thousands of pounds, less expensive systems should be used with caution.
Many people are gaining access to CUSeeMe, which requires no more than the Shareware application, an Ethernet connection with an IP (Internet Protocol) address and a camera. The software is free and provides video communication at up to 25 frames a second.
As a consequence the most prevalent form of video communication at the moment in higher education is by CUSeeMe, and growing.
It is also possible to run multipoint conferences using reflectors. A reflector is a Unix computer, running the reflector program, that enables multiparty conferencing. The CU-SeeMe Reflector was constructed out of necessity, there being no support in the Macintosh TCP/IP facilities for multicast. CU-SeeMe reflectors provide the ability to send multicast but not to receive.
CUSeeMe runs on the MBone, a virtual network that has been in existence since early 1992. It originated from an effort to multicast audio and video from meetings of the Internet Engineering Task Force. The MBone shares the same physical media as the Internet. It uses a network of routers (mrouters) that can support multicast. These mrouters are either upgraded commercial routers, or dedicated workstations running with modified kernels in parallel with standard routers. CUSeeMe complies with the H.261 standard for video encoding, but not with the full range of H.320 standards.
Their main suite of systems if the system 4000 family. There are five systems to choose from ranging from the model 20, a monochrome, desk-top system through to the model 800 boardroom system complete with single or dual 35 inch direct view monitors. The model 150 is the full colour desk top version, the 200 a compact office system, 400 a roll about system, whilst the 600 is a budget executive system, with a 25 inch monitor. All of these systems comply with the CCITT standards and full CIF video format.
PictureTel have produced a system called LIVEShare, which enables sharing and editing of applications in real time to be used in conjunction with their Live PCS100 PC integrated videotelephony product. The video frame rate is 10 or 15 frames per second, which is user configurable. The video component supports full CIF format, running under Windows.
Their larger systems are the VTEL 227 with a 27 inch monitor and the VTEL 235 with the 35 inch monitor. With additional software these can also be used with document sharing, and shared whiteboard facilities.
Satelcom were due to release their C200 videoconferencing system, which is a roll-about system intended for small group meetings (3-4 people per location). It has a 21 inch monitor, runs over ISDN, and is compliant to all CCITT rec ommendations. This system retails at about £20,000. Two other systems make up the new Satelcom range; the C300 (a roll about system with a 28inch monitor, with an option for a 34 inch monitor), and the C600 which additionally allows interactive sharing of documents on a complementary second screen. These two systems run over ISDN, comply fully to CCITT standards and retail at approximately £22,000 and £33,000 respectively.
There are currently nine products in the BT videotelephony range;
They have their own videoconferencing centres (nine in the UK) which can connect to over 450 international videoconferencing centres World-wide. These centres incorporate extensive audio visual facilities. Their top of the range system is the VC5000 Dual Monitor System at about £30,000. These are designed to accommodate larger groups of people, in a conference room environment. The system has two screens plus a self view screen, so that visuals can be displayed in addition to face to face contact on the other screen.
For £10,000 less is the VC5000 Single monitor system, and for about £15,000 is their VC6000 system. This is a more compact alternative, and a true roll-about system.
BT have a range of desk top options including the VC7000 compact system, with a 10 inch screen. This is more like a telephone, with a handset, and numeric keypad. Their smallest system is the Presence unit, a collaborative venture between BT and Panasonic. This is a telephone with full motion and full colour video with a six inch colour LCD display. Running over ISDN, it will be available in February 1995 at approximately £2,500.
BT also produce the relate videophone which runs on the standard telephone network (non ISDN). This plugs into a standard telephone socket, but consequently has a reduced video quality (approximately 4 fps).
BT produce the PC Videophone comprising VC8000 multimedia commmunica tions card and video camera. It can be used in conjunction with other application software, to enable file transfer, simultaneous sharing of documents etc. This retails at approximately £3,500, and runs on ISDN networks.
The main manufacturers and products have been covered in this chapter, but there are many more systems in the market place, which may suit one’s needs. The key factors to consider are price, compliance with standards, ancillary features, and support from the suppliers and/or manufacturers. All of these will interact with each other, and prioritisation of these is a personal decision.
Contents
Home
Graphics Multimedia Virtual Environments Visualisation Contents