Abstract: Highly asymmetrical nature of digital video allows a single Cable Modem Termination System (CMTS) like device to support the transmission over a thousand individual high-quality IP packetized video data channels terminating into low cost cable modem units. A Video Modem Terminating System (VMTS) unit handles housekeeping information. As the amount of upstream housekeeping data are small, even for 1000 simultaneous TV channels, the data can be inserted into the digital video cell streams and packaged within IP packet envelopes. The VMTS unit is equally effective for MPEG-2, MPEG-4, Microsoft Media 9 and other digital encoding of video and audio signals.

Abstract: A conditional access method and apparatus for use with a system for controlling of digital TV program start time. Subscriber access is authorized to digital program streams. Content are divided into a plurality of working periods. Each working period of the plurality of working periods is scrambled with a different working key. A working key of a given period is delivered ahead of the given period. The working key is synchronized with scrambling control bits in an header. working keys are inserted into an entitlement control message (ECM) packet, and the ECM packet is encrypted using a service key. A time period is inserted into the ECM packet during which the service key is valid. A service key is inserted in an entitlement.

Abstract: A method for generating a wide range of clock rates from a single clock. A delta is generated from a first clock signal and a second clock signal. An accumulative offset is generated from adding the delta to a previous accumulative offset for each clock period of the first clock signal. Whenever an overflow is encountered, the value of the accumulative offset is truncated. The second clock signal is interpolated between adjacent values.

Abstract: A system for the delivery of video on demand (VOD). A wireless remote control device generates keystroke signals for controlling a TV display and has a single button for restarting a selected program at a beginning of the selected program. A head-end unit supports separate downstream virtual channels for each separate TV set connected on a common TV feeder-cable; The head-end unit locally records and stores many programs, and transmits each program using a compressed digital format. The Compressed digital format may use MPEG-2 or MPEG-4. The head-end unit has means for protecting against signal theft. A set top unit encapsulates the keystroke signals and transmits the keystroke signals via a two-way channel to the head-end unit.