Abstract: The preferred embodiment of the present invention provides an improved transport demultiplexor that can receive and filter different data types before sending the data to system memory. The preferred embodiment provides a string comparator to facilitate real time filtering of continuous incoming data before loading the data into system memory. The string comparator preferably uses a bit-maskable matching filter that filters system data in real time as the data is being delivered to system memory. When data matching the filter is located, the destination address of that data is determined and delivered to the processor. This allows the processor to quickly locate the desired data and thus facilitates the real time processing of that data.

Abstract: The preferred embodiment of the present invention provides an improved transport demultiplexor that can receive and filter different data types before sending the data to system memory. The preferred embodiment provides a string comparator to facilitate real time filtering of continuous incoming data before loading the data into system memory. The string comparator preferably uses a bit-maskable matching filter that filters system data in real time as the data is being delivered to system memory. When data matching the filter is located, the destination address of that data is determined and delivered to the processor. This allows the processor to quickly locate the desired data and thus facilitates the real time processing of that data.

Abstract: Copy protection is provided at a mass storage device provided in or connected to a decoder for receiving digital transmissions of audio and video program material by virtual scrambling of blocks of data. Non-sequential storage locations for blocks of data are defined in accordance with a key and the file allocation table is encrypted and stored. Thus blocks of data remain intact and need not be decrypted upon playback, reducing processing time, while the program is effectively protected from reassembly without decryption of the file allocation table. The key(s) may be maintained internally within the decoder and need not be shared, thus avoiding a need for user identification and/or authentication. Software for encryption, including keys may be downloaded to the decoder through the same transmission link used for transmission of data files that may be encrypted in response to control signals or flags transmitted with data files to be protected.

Abstract: An access control function for an integrated system is provided which determines data access based on the master id of a requesting master within the system and the address of the data. The access control function can be inserted, for example, into the data transfer path between bus control logic and one or more slaves. In addition to determining whether to grant access to the data, the access control function can further qualify the access by selectively implementing encryption and decryption of data, again dependent on the data authorization level for the particular functional master initiating the request for data.

Abstract: Two data streams derived from a transmitted data stream are remultiplexed with a coarser granularity for storage in data blocks which assure that corresponding portions of each of the two data streams are made available in the same data block. The data streams are buffered in queues from which sub-blocks are transferred as buffer sections having sizes corresponding to relative bit rates therein in the order the sub-blocks are filled, preferably using bytes to interrupt processing. Thus, the sub-blocks will be grouped into data blocks in accordance with the correspondence of the data streams such as the time correspondence of audio and video data. As applied to digital video data transmissions, a system time clock (STC) value is stored in a sub-block header and/or a data block header and, using a look-up table or other arrangement for estimating a storage location, a data block can be retrieved from storage in accordance with a target STC value.

Abstract: Data corrupted or lost in transmission over a lossy digital transmission link is replaced and/or omitted from data presented in connection with storage to and read out from a mass storage device. Different procedures are used to conceal artifacts corresponding to errored data based upon valid data preceding and following the error in a data stream and a size of the error.

Abstract: An access control function for an integrated system is provided which determines data access based on the master id of a requesting master within the system and the address of the data. The access control function can be inserted, for example, into the data transfer path between bus control logic and one or more slaves. In addition to determining whether to grant access to the data, the access control function can further qualify the access by selectively implementing encryption and decryption of data, again dependent on the data authorization level for the particular functional master initiating the request for data.

Abstract: An apparatus and method for extracting vertical (V-SYNC) and horizontal (H-Blank) sync signals from a digital composite sync signal (C-SYNC) of a master video source for use in controlling a second video source, which allows for an adjustable delay relationship between the C-SYNC from the master source and the generated H-Blank. The present invention also provides a system and method for varying the responsiveness or gain of the genlocking circuit used to synchronize the system pixel clock frequency of the second video source to that of the master video signal.

Abstract: A multi-path access control device for an integrated system is presented which allows simultaneous access to multiple external devices coupled thereto by multiple functional units. The multiple functional units are coupled to the shared access control device across two or more high speed, shared data buses. The control device includes multiple bus ports, each coupled to a different data bus, and a non-blocking crossbar switch coupled to the bus ports for controlling forwarding, with zero cycle latency, of requests from the functional units. Multiple external device ports are coupled to the non-blocking crossbar switch for receiving requests forwarded by the crossbar switch, and each external device is coupled to a different external device port. The crossbar switch allows multiple requests at the bus ports directed to different external devices to be forwarded to different external device ports for simultaneous accessing of different external devices coupled thereto pursuant to the multiple requests.