Abstract: The invention is directed to a method comprising intercepting a download request, originally directed to an original destination, for content; processing the download request; searching for the content in a local cache; servicing the download request from the local cache if the content is found in the local cache; forwarding the download request to the original destination if the content is not found in the local cache; and notifying a server of the intercepted download request, wherein the server transmits the content to one or more clients via one or more video channels. The invention is also directed to a method comprising listening for requests from a client; receiving, from the client, an intercepted download request for content; managing the amount of available bandwidth in one or more video channels; encapsulating the content in a format suitable for video channels; and transmitting the content to one or more clients via one or more video channels.

Abstract: Roughly described, a system and method for delivering video content to a user's client device in a video-on-demand (VOD) system, which includes providing a collection of video segments, the segments having a predefined default sequence; establishing a streaming video session according to a session-oriented protocol; transmitting toward the client device a script executable by the client device, the script operable to transmit navigational codes toward the head-end equipment in response to and indicating user selection among navigational choices; beginning transmission of the video segments in the collection toward the client device in accordance with the default sequence of segments; and in response to receipt of one of the navigational codes, and without tearing down the streaming video session, altering the transmission sequence to jump to the segment that the user selected.

Abstract: The invention is directed to a method for providing client-server data transfer over a Hybrid Fiber Coax network, comprising interfacing, at a client, a video channel, intercepting a content request made from an end-user computing device, notifying a server of a relevant intercepted message via one of using an interactive channel and tagging the request, selecting content sent by the server over the video channel, processing the content selected so as to return it to its IP traffic format, and forwarding the content in its IP traffic format to the end-user computing device.

Abstract: The invention is directed to a method for providing client-server data transfer over a Hybrid Fiber Coax network, comprising interfacing, at a client, a channel, wherein the channel is one of a video channel and a DOCSIS channel, intercepting a content request made from an end-user computing device, notifying a server of a relevant intercepted message via one of using an interactive channel and tagging the request, selecting content sent by the server over the channel, processing the content selected so as to return it to its IP traffic format, and forwarding the content in its IP traffic format to the end-user computing device.

Abstract: A scalable video compression method and apparatus for encoding an input frame sequence having temporally sequential frames includes partitioning each of the frames of the input frame sequence into a top field and a bottom field to form a base layer sequence of fields and an enhancement layer sequence of fields. The base layer sequence and the enhancement layer sequence each comprise temporally alternating top and bottom fields of the partitioned frames of the input frame sequence. The base layer sequence and the enhancement layer sequence are encoded, wherein at least one field of the enhancement layer sequence is encoded in dependence upon at least one of the fields of the base layer sequence.

Abstract: Methods and systems for video coding are provided. A method includes receiving a digital video stream. The digital video stream includes multiple sequential independent frames. The method further includes storing a first frame of the digital video stream. The method also includes encoding a second frame of the digital video stream using motion compensation with the stored first frame as a reference.

Abstract: Optical transceivers used in data communications equipment are typically bidirectional and require two-way communications in order to maintain their operability. However, in some applications such as cable television, the traffic is highly unbalanced with very high bandwidth requirements in one direction and minimal bandwidth requirements in the opposite direction. Hence for such efficient and cost effective one-way communication applications, unidirectional fiber optic transceivers are useful. There is provided here a unidirectional transceiver provided internally with a keep-alive signal generator to enable unidirectional transmissions. The keep alive signal is, for instance, idle characters for a Gigabit Ethernet communication system, or any other suitable handshake signal which provides the desired operability.

Abstract: An optical receiver, for use for instance in an analog optical communications system such as a return path in cable television, operates over a wide range of input power to its photodetector. This is accomplished by providing in the optical receiver a series of RF amplifier stages where at least one of the stages includes a fixed attenuator and a parallel amplifier with switches suitably connected so that, at any one time, only one of the fixed attenuator or the amplifier is in the signal path. The switches are controlled so that the dynamic range of the optical receiver is improved in order to make gain reduction more accurate. Hence by redirecting the RF signal path to either the attenuator or amplifier of the amplifier stage, excessive noise and distortion by the amplifier stage are eliminated or reduced.

Abstract: This invention relates to novel chemical compositions and manufacturing methods for producing electro-conductive, metal-ceramic materials having improved structural stability to operate at high temperatures in oxidizing atmospheres.

Abstract: An optical transmitter for coarse wavelength division multiplexed (CWDM) optical communication systems uses a conventional laser (e.g. laser diode) and in addition a heater element is provided thermally coupled to the laser. A thermal sensor and associated control circuit drive the heater so as to control the power consumed by the heater to assure that the laser's temperature is not lower than a predetermined minimum working temperature. When the sensed laser temperature is above this predetermined minimum temperature, the control circuit turns off the heater. The total operating range of the transmitter in terms of ambient temperature is thus extended beyond its inherent operating range by the maximum laser temperature rise created by the heater. This allows a CWDM optical transmitter with the heater and control circuitry to be used in outdoor applications where a wide ambient temperature range is required.

Abstract: A statistical multiplexing apparatus and method for encoding and combining a diversity of video signal resolutions and formats. Higher resolution signals are reduced to lower resolution signals for simplifying the a priori statistics gathering process. Alternately, input video signals in multiple formats are converted to a single common format prior to their application to an a priori statistics gatherer. A storage device contains the a priori statistics which are indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The original video signals are applied to encoders which compress the signals in accordance with bit allocation decisions generated by a statistics computer. The statistics computer uses the a priori statistics from the storage device to generate bit allocation decisions. Subsequently, the statistics computer may use both the a priori statistics and the a posteriori statistics received from the encoders in allocating bits.

Abstract: Apparatus and methods for multiplexing data received from a plurality of sources to a communication channel. Each of the sources is assigned to one of at least two scheduling layers based in part upon one or more bit rate characteristics of the sources.

Abstract: In hybrid fiber coaxial cable networks such as used in cable television where two-way digital communications are desired, a distributed termination system is provided. In such a system the home terminals are digital terminals, such as digital set-top boxes or cable modems using bi-directional transmission standards. The functionality of the head end controller in a conventional system is in this system distributed between the head end and the fiber nodes which link the coaxial cable and optical fiber portions of the system. Thereby the upstream detection takes place in the fiber nodes rather than in the head end by placing upstream burst receivers in the fiber nodes. Further there is a distributed method to enable this by providing synchronization and calibration control between the head end and the fiber nodes. Also, the return path is a digital return path supported by having the burst receivers located in the fiber nodes.

Abstract: In one embodiment, an edge or border processor modifies the undisplayed edges of an uncompressed video input signal before it is applied to a compression engine. This configuration reduces the number of bits used in the compression process. The undisplayed edges of the video signal are modified either by being turned black, by blurring, or by copying, depending on the application. As an aspect of this embodiment, the edge processing functions are integrated into the compression engine or video encoder. In another embodiment, edges of the uncompressed video input signal are not preprocessed prior to encoding the signal. Instead, a video encoder includes a motion estimator with special edge processing that, e.g., uses only zero motion vectors for edge macroblocks. Further, the video encoder includes a quantization processor having a special edge processor. In either embodiment, the configuration of the output bit stream is compatible with the MPEG-2 standard.

Abstract: A method is provided for transcoding, i.e., decoding, and re-encoding, a previously encoded video signal, to a second encoded representation. A number k>1 of previously encoded pictures of the previously encoded video signal are received in a buffer. Each of the k previously encoded pictures in the buffer is scanned to gather information on each of the k previously encoded pictures. An encoding parameter is allocated to a first one of the k previously encoded pictures which precedes each other one of the k previously encoded pictures in encoded order of the previously encoded video signal. The encoding parameter is allocated based on the information gathered for each of the k previously encoded pictures. The first previously encoded picture is decoded to produce a decoded picture. The decoded picture is re-encoded to generate a re-encoded picture in a second encoded representation of the video signal. The re-encoding is performed in a fashion which depends on the encoding parameter allocated thereto.

Abstract: An optical transmission system that includes an optical amplifier coupled to the input of an optical modulator having at least two complementary output ports for providing complementary modulated optical output signals can be used such that the relative intensity noise (RIN) associated with the optical amplifier is coupled into the modulated optical output signals as common mode noise and can therefore be eliminated using a differential detection scheme. Removing the RIN associated with the optical amplifier advantageously increases the carrier to noise ratio (CNR) for the optical transmission system.

Abstract: An amplifying circuit and associated method that outputs a distortion-free signal. The circuit includes an output amplifier driven by two intermediate amplifiers having differing gain factors. The intermediate amplifiers are coupled via an attenuator, a phase shifter, a signal splitter, and signal combiner and produces a predistortion signal that cancels the distortion signal generated from the output amplifier. Another similar amplifying circuit includes an additional combiner and splitter loop, and independently cancels the distortion signal generated by the first intermediate amplifier and the distortion signal generated by the output amplifier.

Abstract: A method and apparatus for recording and playback of transport stream packets including multiplexed audio, video and other data streams. The transport streams may be generated in accordance with an MPEG-2 standard. In a record mode, an arrival timestamp is generated for each input transport packet to be recorded in a peripheral storage device. A given arrival timestamp indicates the arrival time of the corresponding transport packet in the recording system. Each of the transport packets are then stored with their corresponding arrival timestamps. The record mode may utilize a packet identifier (PID) decoder to perform packet filtering such that only incoming transport packets with selected PIDs are stored. In a playback mode, transport packets and corresponding arrival timestamps are retrieved from the storage device and the arrival timestamps are utilized to direct synchronous delivery of the transport packets to, for example, a decoder or a transport stream broadcast system.

Abstract: An RF choke for separating or joining an RF signal and an AC power signal on e.g. a CATV transmission line has a large current carrying capacity. The RF choke uses 14 to 16 gauge magnetic wire in order to carry currents as high as 15 amps. In addition, the RF choke has excellent performance as measured by RF frequency response and hum modulation.

Abstract: A laser transmitter used in an optical communication system provides automatic compensation/stabilization of CNR (carrier to noise ratio) and OMI (optical modulation index) in conditions that would have caused these parameters to change if the compensation circuitry was not employed. The compensation circuitry is an open loop that operates in conjunction with a conventional APC (automatic power control) loop. When certain parameters change (i.e., temperature, laser aging, intentional change in optical power) they will affect the laser DC current (either directly or because of the existence of the APC loop) and as a result the CNR/OMI will change. The compensation circuitry senses the change in the laser DC current and changes the modulating current to the laser as required to minimize changes in CNR/OMI.