MPTS Program Substitution via PCR Extraction and Packet Overwriting
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Solution Overview
Problem
Existing methods for substituting programs within Multiple Program Transport Streams (MPTS) are complex and costly, especially in encrypted multiplexes, as they require de-multiplexing, timing information recovery, and re-multiplexing, which is not feasible due to lack of clear timing information.
Innovation Solution
The method involves overwriting replaced packets at the original MPTS transport rate, recovering the transport rate and timing information of replacement packets, and scheduling their retransmission based on available replaced packet locations, maintaining the original MPTS transport clock to avoid re-multiplexing and re-time stamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If de-multiplexing and re-multiplexing is performed to substitute programs in MPTS, then program substitution is achieved, but device complexity and operational cost increase significantly
Solution Approach 1:
The patent extracts only the essential timing information (PCR - program clock reference) from the encrypted MPTS without requiring full de-multiplexing. By isolating and utilizing just the timing data needed for packet scheduling, the system achieves program substitution without the complex re-multiplexing process, thus reducing device complexity while maintaining substitution capability
Solution Approach 2:
The system performs preliminary recovery of timing information before packet substitution. By pre-extracting PCR values and calculating replacement packet locations in advance, the system prepares all necessary scheduling data beforehand, eliminating the need for complex real-time de-multiplexing and re-multiplexing operations
2Adaptability or versatility
If de-multiplexing and re-multiplexing is performed to substitute programs in MPTS, then program substitution is achieved, but operational cost increases
Solution Approach 1:
The patent extracts only the essential timing information (PCR - program clock reference) from the encrypted MPTS without requiring full de-multiplexing. By isolating and utilizing just the timing data needed for packet scheduling, the system achieves program substitution without the complex re-multiplexing process, thus reducing device complexity while maintaining substitution capability
Solution Approach 2:
The system uses the existing MPTS timing information itself to drive the substitution process. By leveraging the original stream's PCR values and transport timing, the system performs self-scheduling of replacement packets without requiring external timing recovery or complex synchronization mechanisms, thereby reducing operational costs
3Manufacturing precision
If timing information is recovered for replacement packets, then accurate packet scheduling is achieved, but processing time increases
Solution Approach 1:
The system performs preliminary recovery of timing information before packet substitution. By pre-extracting PCR values and calculating replacement packet locations in advance, the system prepares all necessary scheduling data beforehand, eliminating the need for complex real-time de-multiplexing and re-multiplexing operations
Solution Approach 2:
The patent uses copying of timing reference values (PCR) from the original MPTS to the replacement packets. Instead of recovering complete timing information streams, the system copies only the essential timing markers and uses them to schedule replacement packets, achieving precise scheduling with minimal processing overhead
Data Source
AI summary
Provided are methods and systems for substituting programs within an existing multi program transport stream (MPTS). Methods can include identifying a first packet associated with a first input program, determining if the first packet is a packet to be replaced, substituting a second packet for the first packet if the first packet is the packet to be replaced, and applying a timestamp at the stream processor to the second packet with a time for the second input program.