Harmonic Inc.

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. The playback mode may detect a timestamp discontinuity code in one or more of the arrival timestamps, and adjust the playback system time clock accordingly. The playback mode may also provide null packet interleaving in which a selectable number of null packets are inserted between each valid transport packet to thereby provide a selectable fixed-rate transport packet output. The recording and playback features may be implemented using a spooler card and a storage controller card incorporated into an otherwise conventional personal computer.

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: A method and apparatus for non-seamless splicing of audio-video transport streams configured in accordance with MPEG-2 or other suitable techniques. A first transport stream is to be spliced with a second transport stream at a splice point. The first stream is configured such that the final first stream frame to be displayed will be a black frame or will have another suitable characteristic. Null packets are then delivered in place of the first stream transport packets for a predetermined period of time after the splice point. The predetermined time is generally greater than the sum of the splice decoding delay associated with the splice point and the maximum frame duration in the first stream. The transport packets of the second stream are then delivered. Null packets may be again delivered for a period of time sufficient to allow the final frame of the second stream to be displayed. The final first stream frame can be guaranteed to be a black frame by directing a digital stream insertion device to insert a black I-frame followed by an end-of-sequence code into the first stream. Alternatively, the final first stream frame could be forced to black during an encoding operation, and an end-of-sequence code could then be inserted at the splice point.

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. An apparatus is also disclosed for carrying out the method including a buffer, a scanner (for performing the scanning and allocating steps), a decoder and an encoder.