Reconstitution of program streams split across multiple packet identifiers
First Claim
1. A method of providing multiple packet identifier (PID) information for a multiple carriage television content delivery system, comprising:
- constructing a program association table (PAT) that associates programs with primary PIDs;
constructing a plurality of program map tables (PMT), one for each program in the PAT;
constructing a lookup table that maps at least one primary PID that identifies a portion of a program encrypted under a first encryption system to at least one shadow PID that identifies a duplicate of the same portion of the program encrypted under a second encryption system; and
at a television transmitter device, broadcasting the PAT, the PMTs and the lookup table over the television content delivery system.
1 Assignment
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Accused Products
Abstract
A method and apparatus for reconstituting packetized data streams representing a television program when the program uses multiple packet identifiers (PID) as in selective encryption schemes. Transmission of multiple sets of system information (SI) is avoided by incorporating a lookup table within a private data packet. A dual buffer arrangement in the set-top box provides ease of reconstitution of a data stream by generation of an interrupt upon receipt of a packet with a shadow PID. The buffers are toggled as a result of the interrupt and a corresponding packet can be found either at the beginning of the newly active buffer or the end of the inactive buffer. The stream of packets representing a program can then be reconstituted by creation of a new packet having the primary PID and shadow packet'"'"'s payload.
519 Citations
51 Claims
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1. A method of providing multiple packet identifier (PID) information for a multiple carriage television content delivery system, comprising:
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constructing a program association table (PAT) that associates programs with primary PIDs; constructing a plurality of program map tables (PMT), one for each program in the PAT; constructing a lookup table that maps at least one primary PID that identifies a portion of a program encrypted under a first encryption system to at least one shadow PID that identifies a duplicate of the same portion of the program encrypted under a second encryption system; and at a television transmitter device, broadcasting the PAT, the PMTs and the lookup table over the television content delivery system. - View Dependent Claims (2, 3)
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4. A method of demultiplexing a data stream having multiple packet identifiers for a program carried out at a television receiver device, comprising:
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at the television receiver device; receiving a program association table (PAT) that associates programs with primary PIDs; receiving a program map table (PMT); receiving a lookup table relating primary PIDs to shadow PIDs; determining, from the PMT and the lookup table that a program is associated with both a primary PID that identifies a portion of the program encrypted under a first encryption system and a shadow PID that identifies a duplicate of the same portion of the program encrypted under a second encryption system; and setting a PID filter to permit passage of packets having both primary and shadow PIDs. - View Dependent Claims (5, 6, 7)
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8. A method of constructing a stream audio/video of data packets having related primary and shadow packet identifiers (PIDs), the packets having headers and payloads, comprising:
at an audio/video receiver device; receiving an incoming audio/video data stream having packets with the related primary and shadow PIDs, where the related primary and shadow PIDs each identify duplicated portions of an audio/video program where one of the duplicated portions is encrypted under a first encryption system and another of the duplicated portions is encrypted under a second encryption system, respectively; providing a stream of packets having the primary PID to a first buffer; detecting a packet having the shadow PID and a shadow payload in the incoming data stream; switching the stream of packets having the primary PID to a second buffer in response to the detecting; and searching a last packet stored in the first buffer for a packet corresponding to the packet having the shadow PID. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of constructing a stream of digital television data packets having related primary and shadow packet identifiers (PIDs), the packets having headers and payloads, comprising:
at a digital television receiver device; receiving an incoming digital television data stream having packets with the related primary and shadow PIDs, where the related primary and shadow PIDs each identify duplicated portions of a program with one duplicated portion encrypted under a first encryption system and another duplicated portion encrypted under a second encryption system, respectively; providing a stream of packets having the primary PID to a first buffer; detecting a packet having the shadow PID and a shadow payload in the incoming data stream; switching the stream of packets having the primary PID to a second buffer in response to the detecting; and searching a first packet stored in the second buffer for a packet corresponding to the packet having the shadow PID. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of constructing a stream of digital television data packets having related primary and shadow packet identifiers (PIDs), the packets having headers and payloads, comprising:
at a digital television receiver device; receiving an incoming digital television data stream having packets with the related primary and shadow PIDs, where the related primary and shadow PIDs each identify duplicated portions of a program where one duplicated portion is encrypted under a first encryption system and another duplicated portion is encrypted under a second encryption system, respectively; providing a stream of packets having the primary PID to a first buffer; detecting a packet having the shadow PID and a shadow payload in the incoming data stream; switching the stream of packets having the primary PID to a second buffer in response to the detecting; and searching a first packet stored in the second buffer and a last packet stored in the first buffer for a packet corresponding to the packet having the shadow PID. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of constructing a stream of digital television data packets having related primary and shadow packet identifiers (PIDs), the packets having headers and payloads, comprising:
at a digital television receiver device; receiving an incoming data stream having packets with the related primary and shadow PIDs, where the related primary and shadow PIDs each identify duplicated portions of a program where one duplicated portion is encrypted under a first encryption system and another duplicated portion is encrypted under a second encryption system, respectively; providing a stream of packets having the primary PID to a first buffer; detecting a packet having the shadow PID and a shadow payload in the incoming data stream; switching the stream of packets having the primary PID to a second buffer in response to the detecting; determining a memory address for a storage location in the first buffer at a time of the detecting; and searching for a packet stored at approximately the memory address in the first buffer for a packet corresponding to the packet having the shadow PID. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
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44. A digital television receiver apparatus that reconstitutes/reconstructs a stream of data packets having related primary and shadow packet identifiers (PIDs), the packets having headers and payloads, the receiver comprising:
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a micro computer; a first primary packet buffer; a second primary packet buffer; a demultiplexer receiving an incoming data stream having packets with the related primary and shadow PIDs, where the related primary and shadow PIDs each identify duplicated portions of a program where one duplicated portion is encrypted under a first encryption system and another duplicated portion is encrypted under a second encryption system, respectively, and providing a stream of packets having the primary PID to one of the toggled primary packet buffers; means for detecting a packet having the shadow PID and a shadow payload in the incoming data stream; an interrupt handler that generates an interrupt as a result of detecting the packet having the shadow PID; means for toggling the stream of packets having the primary PID to the other of the first and second primary packet buffers in response to the interrupt; and program means running on the microcomputer for identifying a location of a packet adjacent the detected packet at least one of the first and second primary packet buffers. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51)
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Specification