Distribution of full motion video data has evolved from early television broadcasting to meet viewer demand. Earliest video distribution was by point-to-point wiring between a camera and a video monitor. This was followed by scheduled television broadcasting of programming over the public air waves. In the 1960s, Community Antenna Television (CATV) was chartered to provide off-air television signals to viewers in broadcast reception fringe areas. Later, under FCC regulation, the CATV industry was required to provide local access and original programming in addition to off-air broadcast signal distribution.
In response, several sources of cable network programming were established. Because of the wide bandwidth available on cable television systems, additional channels were made available for the new programming. However, programming was generally prescheduled, with the viewer left to tune to the designated channel at the appointed time to view a particular program.
To increase revenues, cable television systems have initiated distribution of premium channels viewable only by subscribers having appropriate descramblers. The descramblers are tuned to receive only premium channels, descramble the video and audio information and supply a signal capable of reception on a standard television set.
Pay-per-view programs, which evolved later, include recently released movies, live concerts and popular sporting events. Subscribers wishing to view a pay-per-view program place an order with the cable operator. At the designated time, the subscriber's descrambler is activated to permit viewing of the pay-per-view programming. However, the subscriber is restricted to viewing the programming at the scheduled time. There is no capability of delivering programming to a subscriber on demand, that is, immediately or at a subscriber-specified time and date.
In the early 1980s, technological advances resulted in the proliferation of Video Cassette Recorders (VCR), establishing a second course for video programming distribution. Pre-recorded video programs are now available for sale and rental to VCR owners. Using a VCR, the viewer selects from among many titles available for sale and rental, and views the program when convenient. The VCR owner further has the capability to selectively view the programming using special functions of the VCR, such as pause, fast forward, reverse, slow motion, etc. The viewer can thus manipulate and replay portions of the program at will.
The penalty for this convenience, however, is in the necessity to travel to the local video rental/sales store, if necessary wait for a popular video program tape to become available, once the program is obtained return home to view it and then revisit the video store to return the tape.
Telephone lines have been suggested as an alternative means of video distribution in Goodman et al., U.S. Pat. No. 5,010,319 and Kleinerman, U.S. Pat. No. 4,849,811. However, systems using the public switched telephone network (PSTN) are often bandwidth limited, providing only still frame or video conferencing capabilities. Because telephone system carriers for the most part use the PSTN only for connectivity between subscribers, there is no capability for dynamic routing of digitized video without dedicated leased, wide bandwidth circuits. Telephone line based systems also fail to provide acceptable VCR type functional control of the programming.
Copending application Ser. No. 07/766,535, filed by the assignee of the present invention on Sep. 27, 1991, entitled PSTN ARCHITECTURE FOR VIDEO-ON-DEMAND SERVICES and upon which the present invention is an improvement, describes a so-called Video-on-Demand service that provides video programming to subscribers over the PSTN. A menu of video programming information is accessible at the subscriber's premises. The subscriber may transmit ordering information via the PSTN to the independent video information providers. Video programming may be accessed and transmitted to the subscriber directly from a video information provider (VIP) or through a video buffer located at a central office (CO) serving the subscriber.
The VIP transmits coded digital video data over wideband PSTN supplied connectivity to a central office. The video data may be buffered at the central office for transmission over a POTS line to the subscriber. A subscriber may use either a standard telephone instrument over the PSTN or a dedicated control device over an ISDN packet network to order the video programming. Such a device is located at a television set of the subscriber and permits a display of the program menu on the television screen.
Connectivity between the central office and the subscriber for transmission of video data is provided by an asymmetrical digital subscriber line (ADSL) system. ADSL interface units perform multiplexing of digital video information with voice information to be transmitted to the subscriber and support transmission on the ISDN packet data network of a reverse control channel from the subscriber to the central office.
However, video-on-demand service does not include an integral library of video program material, hence enabling only limited storage capabilities for video and audio data supplied by a VIP. Enhanced functionality is required to efficiently support multiple program storage. Furthermore, to support network management, a need remains for a system which dynamically interacts with network facilities to reconfigure network resources in real-time and in response to information requests.
Furthermore, certain operational enhancements have been found to be desirable in the video-on-demand service described in the aforementioned parent application. For example, it is occasionally desired to order a video program from the subscriber's office to be played later at the premises of the subscriber. On the other hand, the subscriber must be home and remember to turn a decoder on at the reserved time, to watch the requested program. If not, the subscriber will not have the opportunity to view the selection but will be charged for it anyway. Hence, it would be desirable to transmit the program and enable a charge to be incurred only if it can be determined that the subscriber is going to view the program.
In accordance with video-on-demand service as described in the copending application, the subscriber can order any programming from the video information provider through the telephone keypad or remote control unit. However, the unrestricted ability of anyone at the subscriber's residence to place an order for any programming is undesirable, for example, where children are involved. It would be desirable to restrict the ability of viewers to order only those types of programming they are permitted to view.
Accordingly, a broad object of the invention is to implement video programming on demand using components of the PSTN.
Another object of the invention is to enable access by a telephone subscriber to multiple sources of video programming over the PSTN.
Still another object of the invention is to enable subscribers of the PSTN to have real time control of video programming delivery to their television sets.
Another object is to enable a subscriber to select video programming from a remote location and receive the selection at the subscriber's premises.
A further object of the invention is to ensure that the video program decoder at the subscriber's premises is turned on before a previously ordered selection is transmitted.
Still another object is to establish service constraints that prevent an unauthorized requester, e.g., a child at the subscriber's premises, from ordering restricted programming.