Telecommunications, especially as it relates to video, has been a regular news item for the past two years. Numerous articles have appeared in the popular press that describe the coming availability of 500 or more channels received through local cable TV (CATV) service. Other articles describe something known as "video dial tone", although this service is not at all well defined. In addition, news stories appear almost daily about how the telephone companies, cable television companies and other telecommunications and entertainment companies have been positioning themselves to take advantage of new developments in telecommunications technology.

This presentation will briefly explain why this high interest in telecommunications and video has surfaced recently, and some of the potential issues related to the future of video and data net-works. While most people have only experienced one-way broadcast video, interactive video has been an anticipated technology from the earliest days of television. It has been a technology waiting to happen. Interactive video has appeared in almost all of our popular depictions of the future, from the cartoon show The Jetsons, to the comic strip Dick Tracy, to the endless series of Star Trek television shows and movies. Interestingly almost all of these depictions focus on the use of interactive video for face to face communications. Our collective idea about interactive video has been molded by the idea of the videophone, a technology first demonstrated at the 1960 World's Fair.

2.THE APPLICATIONS FOR INTERACTIVE VIDEO

While face to face communications will be a logical application of interactive video, I believe it will not be the application that propels interactive video into a high—demand technology. How often do you really want to, or need to, see the person with whom you are having a telephone conversation – especially if the picture will drive up the cost of the call? As the telephone companies are finding out, not very often. But imagine what you can do if you can plug in your portable video camera or camcorder into your telephone jack and send real time video with voice describing and showing virtually anything in your environment. People will be sending, in real time, a baby's first birthday to distant relatives, or showing a distant potential buyer the details of a restored antique car, or showing the family physician the cut on Johnny's arm so the doctor can determine whether or nor Johnny needs to go the emergency room. The portable, easy to use, camcorder is the logical extension to the telephone (Stahl, 1993). Over 60% of homes in the U.S.A. have camcorders, which are almost exclusively used for videotaping. If they can also be used as an adjunct to, or replacement for, the telephone, it is reasonable to assume home owner-ship of portable video cameras will soar. This is especially true when a camera that is only used for transmitting images, rather than recording them, would cost less than $100. The early descri-bers of the future generally missed these mobile applications because they focused on the video display and not the camera. The idea of the average person owning their own fully functioning video camera is, in fact, quite recent.

3. TECHNICAL TELECOMMUNICATIONS ISSUES RELATED TO VIDEO

Historically, the limiting factor that has inhibited the development of interactive video ser-vices has been the capacity of the telecommunications network. This capacity is usually referred to by the term "bandwidth". The videophone demonstrated in 1960 simultaneously used over 4,000 of AT&T’s copper wires to transmit an image. In 1960 such a videophone call would have cost in excess of $1,000 per minute! However, the shift from analog to digital technologies for transmission of all types of communications along with the converging developments in two areas, network bandwidth and video compression, are making reasonable cost interactive video possible.

Network bandwidth has been increasing rapidly and will continue to do so for the foresee-able future. Until recently public switched networks, such as those operated by the telephone industry, have provided bandwidths of 64K bits per second (Kbps), also known as a DS0 circuit, and 1.5 million bits per second (Mbps), also known as a DS1 or T1 circuit. More recently 45 Mbps, also known as DS3 or T3 circuits have become fairly standard. The telecommunications industry is rapidly developing switch technologies such as Asynchronous Transfer Mode (ATM) and transmission technologies, such as Synchronous Optical Network (SONET) that will likely provide bandwidth in excess of two billion bits per second (Gigabits or Gbps) by 1995.

A normal video signal in digital form for a single program requires over 90 million bits per second to be transmitted. The standard telephone circuit, on the other hand, only provides 64 thousand bits per second of transmission speed. As can be readily seen, not even the DS3/T3 networks can accommodate normal video transmission. While higher speed networks, such as ATM/SONET are being developed, they will likely be far too expensive to devote exclusively to video transmission.

Compression is a means of removing portions of the video signal so that it requires less bandwidth. Normal video consists of approximately 30 frames per second. While compression algorithms remove many types of information from the video signal such as color and intensity information, the most noticeable effects come from the fact that compression reduces the number of video frames per second transmitted. Video can be compressed by 50%, down to 45 Mbps or a T3 circuit, with virtually no noticeable effect. At this compression approximately 24 frames per second are being transmitted. However, the cost of leasing a T3 circuit is expensive, often equiva-lent to the cost of leasing 675 telephone lines.

At 1.5 Mbps (T1) compression, video is being transmitted at the rate of approximately 20 frames per second. At this rate some ghosting of motion becomes apparent. As the compression become greater (768 Kbps, 384 Kbps, 128 Kbps and 64 Kbps) ghosting becomes more noticeable and problems arise such as lip movements not being synchronized with the voice. The more highly compressed video, such as Integrated Services Data Network (ISDN) video at 128 Kbps is primarily geared for desktop interactive video conferencing, where the video appears as a small window on a desktop computer. Video which requires less than about 45 Mbps of bandwidth is generally not considered "full motion" video. Full motion is generally considered to be visually equivalent to the video received from standard analog television broadcasts or CATV networks. However, it is anticipated that eventually "full motion" video will be defined by the developing Motion Picture Engineering Group II (MPEG II) standard which will only require 6 Mbps of bandwidth. The combination of increasing bandwidth and video compression is making inter-active video feasible today. As compression techniques improve, so will the quality and accepta-bility of the video.

Overall bandwidth capacity is not the only technical limitation to transmitting video over digital networks. Most existing digital network technologies slow down as the network traffic increases. This slowing down is known as network latency. Network latency is usually not a problem with transmitting data, which does not require a constant stream of bits to be sent, like voice and video does. However, having video slow down and speed up randomly would be unacceptable to users. The developing technologies, such as ATM and SONET, will allow video and other "synchronous" data, such as voice and multimedia to be sent at a "real time" speed.

The increased bandwidth of the networks and the development of fast switching and trans-mission technologies is due to the increasing use of fiber optic cable by the network providers such as the telephone and CATV companies. Fiber optic cable is being used initially because the cost has become competitive with the copper cables used in the past, and fiber optic cable has a longer life span and is much more reliable and easier to maintain than copper cable. Fiber optic cable can accommodate much greater bandwidth than is physically possible with copper cable. Some estimate that the theoretical bandwidth limit for fiber optic is around 25,000 Gbps! The challenge to the public network providers is how to effectively use this greatly increased available bandwidth. Electronic mail, data file transfers and voice are not heavy bandwidth users. Video and related applications such as high resolution graphic images and multimedia do, on the other hand, require extensive bandwidth.

4. THE ROLE OF THE TELEPHONE AND CABLE TELEVISION COMPANIES

There are significant differences between the major public network providers. The telephone companies and related public network providers have large amounts of bandwidth available in their major "trunk lines", but the bandwidth they provide to the individual customer is usually quite limited. In the case of the telephone companies this bandwidth is usually 64 Kbps. The telephone companies do have connections in over 90% of the homes and businesses in the U.S.A. While the telephone companies and other public network providers can supply their customers with higher bandwidth, these circuits are not inexpensive. Some telephone companies are currently experimenting with a technology known as Asymmetrical Data Service Loop (ADSL), which provides 64 Kbps going out of the customer’s home or office, but provides up to 1.5 Mbps going into the customer’s home or office over existing telephone wires. The interest in ADSL currently is in providing broadcast video from digitally stored video on "video servers". It is not suitable for interactive video.

The CATV companies, on the other hand, have high bandwidth going into over 60% of the homes in the U.S.A. and can reach an additional 15% without having to install additional trunk lines. This bandwidth is normally delivered to the home by copper coaxial cable, but it has adequate bandwidth to provide interactive video services. However, the CATV companies do not have the large, highly coordinated regional networks that the telephone companies do. Also, the bandwidth into homes and offices provided by the CATV companies is not currently configured for interactive services. The large majority of the bandwidth goes from the CATV company into the customer’s premise. There is only a very small amount of "reverse bandwidth" allocated to go from the customer to the CATV company. The CATV companies need to re-engineer their sys-tems to provide for a more balanced allocation of bandwidth to support interactive video.

While there is a great deal of competition between the telephone companies and CATV to capture the anticipated market for interactive video, it is reasonable to assume that cooperative ventures between the telephone companies and the CATV will become common. Among other things, it is estimated that it would cost the telephone companies between $700 and $1,000 per household to duplicate the bandwidth provided by the CATV.

Another difference between the major network providers is their understanding of interactive video. The telephone companies understand interactivity primarily through their experiences with telephone service, including various types of conferencing services. The CATV companies on the other hand, view interactive video from the perspective of commercial television and entertain-ment, such as home shopping. A recent issue of Time (Elmer—Dewitt, 1993; Zoglin, 1993) pro-vides a very good overview of this market for interactive video. The difficulty is that while the market for interactive video includes both the applications anticipated by the telephone and CATV, interactive video will likely include many unforeseen applications. Interactive video has always been difficult to market because it has not been common or widely available. Operators of existing full motion interactive networks, such as the CONCERT and Vision Carolina networks in North Carolina, commonly have found interactive video difficulty to explain, but easy to demons-trate. These video network operators report that people immediately understand and begin to identify applications for interactive video once they experience it. In order to market interactive video, companies need to be able to articulate the value of the technology to potential users – something that is very difficult to do with interactive video. These companies can only guess what the market is likely to be. In general, the developers and early providers of new technologies have not been good about predicting the technology’s real value. In the meantime the companies must move forward with very expensive investments in high speed network technology in order to be well—positioned for the future. This investment is made risky because no one wants to buy the technology too early, nor do they want to invest in the wrong technology. The latter point is especially difficult because the technologies are still in the developmental stages and there are many competing technologies and many standards have yet to be established.

A major issue network providers must face is pricing. These companies historically have been in the business of selling constant bandwidth circuits. The telephone company provides as a telephone connection a constant 64 Kbps circuit which is available 24 hours per day, 7 days per week, whether or not the bandwidth is actually needed. While George Gilder (Kelly, 1993), among others, argues that eventually bandwidth will be so plentiful it will be very cheap, for the immediate future bandwidth will have to be priced on a "bandwidth on demand" basis for inter-active video to be reasonably priced. A user that wants to have a one hour—long video conference that will require 45 Mbps of bandwidth will not want to pay to have that bandwidth all the time if this bandwidth will cost thousands of dollars per month. However, if the user only pays for 45 Mbps for the one hour it is needed, then interactive video becomes affordable. Moving from circuit pricing to bandwidth on demand pricing will require changes in legal restrictions on the telephone and CATV companies currently in place. It will also require a major change within those companies, because they have generally operated on a guaranteed revenue stream from circuit pricing. However, bandwidth on demand pricing will generate a potentially widely variable stream of revenue.

One aspect that is often being underplayed as companies pursue the market for interactive video is that of data on the networks. The common assumption is that if a network can handle interactive video, it certainly has the capacity to handle data. Technically this is true. However, from the service standpoint, it is safe to assume that most users will want both interactive video and data connectivity simultaneously. It has been a common experience with existing interactive video networks that one of the first enhancements of the interactive video network requested by users is data connectivity. Video will not replace the need for data. People will want to exchange data files as they collaborate over video networks. Data will continue to have important uses in such areas as electronic funds transfer, home shopping, and even entertainment. The successful vendors of interactive video services will be those that provide both interactive video and data services together. The telephone and CATV companies generally do not yet understand how to market and support data services like those available through CompuServe™.

5. THE IMPACT OF INTERACTICE VIDEO ON IFORMATION PROFESSIONALS

While all technology is additive, a new technology always changes the way previous techno-logies are used. The railroads did not go away, but their use has certainly been changed by the highways. The same is true for the telephone and its impact on the postal system. Information professionals, whether they are librarians or communications, data processing or video profes-sionals must begin addressing how the advent of pervasive interactive video services will impact the services they provide. It would be a mistake to depend exclusively on the telecommunications industry to develop this market and to assume that interactive video will be a small niche techno-logy. The services will become too important to be ignored by staff responsible for providing information to clients. With the large amount of attention being given to multimedia, it is ironic that interactive video is not considered more often. After all, interactive video, especially when combined with collaborative data exchange and stored video clips, is nothing more than real time multimedia.
 

REFERENCES

Elmer—Dewitt, Philip, "Take a Trip into the Future on the Electronic Superhighway,"Time, 141 (15): 50—55 (1993).

Kelly, Kevin, "When Bandwidth is Free: The Dark Fiber Interview with George Gilder," Wired, 1 (4): 38—41 (1993).

Stahl, Bil, "Will Camcorders Replace PCs? The Impact of Interactive Video on Data Networks," In Martha Williams (ed.). Proceedings of the fourteenth National Online Meeting. Medford, NJ: Learned Information, 1993.

Zoglin, Richard, "When the Revolution Comes What will happen to….", Time, 141 (15): 56—58, 1993.