f you believe the recent claims about interactive multimedia technology, we will soon be able to view movies, play video games, I browse libraries, order pizza, and participate in office meetings (in our bare feet!) from within the confines of our homes. Some critics have called interactive multimedia "a technology looking for an application.'' This skepticism appropriately highlights the distinction between the technology (computers and communications) and the applications that use the technology and make it ubiquitous. There is good reason for the excitement. Interactive systems will give users the flexibility of selecting and receiving specific information using a hybrid paradigm of the TV remote control and information retrieval techniques. This differs from traditional television delivery mechanisms, in which the user is a passive participant receiving what the service provider offers. The availability of enormous communication bandwidth and computing power has made it possible to process and deliver information on a per-user, per-session basis in real time. The ability to process information at the source enables the information provider to extract relevant data and modify their characteristics to specific user tastes. Users of such services will have flexibility in choosing the kinds of information they receive. They can also control, based on individual preferences, the manner and time of receipt of this information. The kind of interaction supported depends to a large extent on the kind of information retrieved and on the particular application under consideration. (Often, service providers distinguish interactive services as consumption services, in which they deliver information primarily one way-like movies-and communication services, in which a bidirectional channel is necessary-like teleconferencing.) A home user interacting with movies requires the system to support virtual VCR capabilities, such as the ability to play, forward, reverse, and pause. Most systems use a remote-control device to browse a menu and select movies on a TV screen ( Figure 5 ). Other interactive features include the ability to avoid or select advertisements, to investigate additional details about news events (through hypermedia, for example), to save or annotate programming for later reference, and to browse, select, and purchase goods. Figure 1 illustrates one example of this technology applied to distance learning. Clearly, the distinction between the computer and the television is blurring. ' Several applications deliberately take advantage of interactive information retrieval and dissemination, such as the Internet tools Mosaic and Gopher. Current Internet growth indicates the demand for these services: There are currently close to 300,000 Mosaic/World-Wide Web, or WWW, sites. However, the transmission characteristics of the Internet are not appropriate for high-bandwidth, low-latency audio-and videobased applications. Telephone and common antenna TV (CATV) cable networks have such capabilities, and they are establishing their own multiservice networks. Developing this new information delivery infrastructure requires considerable planning and effort. While most media attention has focused on what these information systems will deliver, little is said about how they will be assembled or what they will cost. Much of the technology required to support these systems exists, but it is disjoint, and significant efforts in integration are necessary to yield a working end-to-end system. Developing accepted international standards is a first step in the right direction to make this vision a reality, for example, Asynchronous Transfer Mode (ATM) switching in communication and Moving Picture Experts Group (MPEG) standards for video compression. Establishing standards for set-top devices, video-file servers, and metadata databases, standards that enforce interoperability and allow competition among suppliers, is important for such systems to grow. Other issues requiring attention include billing for services, information security, copyrights, user interface design, and indexing schemes for efficient retrieval.
According to Little and Venkatesh, in the interactive services, virtual VCR capabilities and interfaces to view parallel media streams are the most crucial requirement for video on demand system REF .
Prospects for Interactive Video-on-Demand
IEEE MultiMedia
IEEE MultiMedia
Computer Science