AV Stream Processor Segmentation for Timing Modification
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Solution Overview
Problem
Current home gateway devices process both audio video (AV) and non-AV traffic using a general-purpose host processor, which limits efficient processing of AV traffic due to encryption and digital rights management mechanisms, preventing timely modification of presentation timing attributes in AV streams.
Innovation Solution
A dedicated AV stream processor is introduced to handle AV traffic independently, allowing access to transport stream packets without encryption, enabling efficient modification of parameters like presentation time stamps, program clock references, and continuity counters, while the host processor focuses on non-AV traffic processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a general-purpose host processor processes both AV and non-AV traffic uniformly, then device complexity is reduced, but AV traffic processing speed and latency are worsened due to encryption and DRM mechanisms
Solution Approach 1:
The gateway device is segmented into two distinct processor units: a host processor for non-AV traffic and a dedicated AV stream processor for AV traffic. This segmentation allows each processor to be optimized for its specific function, with the AV stream processor handling decryption and AV packet processing independently from the host processor, thereby improving AV processing speed without requiring complete architectural redesign of the entire device.
Solution Approach 2:
An AV stream processor acts as an intermediary component between the encrypted AV traffic source and the host processor. This intermediary performs decryption and initial AV packet processing, freeing the host processor from handling encryption/decryption operations and enabling faster AV traffic processing while maintaining a relatively simple overall device structure.
2Reliability
If encryption and digital rights management mechanisms are applied to AV traffic, then security is improved, but processing time and latency are worsened
Solution Approach 1:
The AV stream processor performs decryption and security-related processing in advance, before AV packets are forwarded to the host processor or output device. By handling encryption/decryption operations proactively in a dedicated processing unit, the system maintains strong security protection while minimizing the time AV traffic spends in the security processing pipeline, thus reducing overall latency.
3Ease of operation
If the host processor handles all traffic uniformly, then ease of operation is improved, but productivity of AV traffic processing is worsened
Solution Approach 1:
The uniform traffic handling approach is segmented into specialized processing paths: the host processor manages non-AV traffic and high-level control functions, while the dedicated AV stream processor handles AV-specific operations including decryption, packetization, and timing attribute modification. This segmentation maintains operational simplicity through clear functional separation while dramatically improving AV traffic processing throughput.
Solution Approach 2:
The AV stream processor is designed as a multi-functional unit that can perform multiple AV-specific tasks: decryption, packet processing, timing attribute modification (PTS, PCR, DTS), and commercial insertion. This multi-functionality in a dedicated processor improves overall AV processing productivity while keeping the host processor's interface simple and easy to operate.
4Manufacturing precision
If presentation timing attributes are modified in encrypted AV streams, then manufacturing precision is improved, but the complexity of processing increases
Solution Approach 1:
The AV stream processor serves as a specialized intermediary that handles the complex task of modifying presentation timing attributes (PTS, PCR, DTS) in decrypted AV packets. By concentrating this precision-critical functionality in a dedicated processing unit with appropriate hardware support, the system achieves accurate timing attribute manipulation without requiring the host processor to handle complex low-level AV packet modifications, thus managing device complexity through functional specialization.
Data Source
AI summary
A system for presentation timing based audio video (AV) stream processing may include a switch device, a first processor, and a second processor. The switch device may be configured to route AV traffic to the first processor for processing and non-AV traffic to the second processor for processing. The first processor may receive transport stream packets that include an audio stream and/or a video stream. The first processor may receive a request to modify presentation timing of the audio stream and/or video stream. The first processor may modify the transport stream packets and/or presentation timing parameters of the transport stream packets based at least in part on the received request. The first processor may provide the transport stream packets to an electronic device. In some implementations, the second processor may be unable to access the content of the transport stream packets in the clear, e.g. due to security considerations.