HDCP Source KSV Capacity Detection Method
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Solution Overview
Problem
HDCP sources often fail to transmit protected content to downstream sinks when they exceed their supported number of Key Selection Vectors (KSVs), leading to undetected transmission failures in video systems.
Innovation Solution
A method involving sequential testing of varying sets of KSVs to determine the maximum number supported by the HDCP source, where the source reads test KSVs and adjusts the number until it enters a failure mode, allowing the system to route protected content only to the supported number of sinks, preventing transmission interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the HDCP source reads more KSVs from the repeater registers, then the system supports more downstream sinks, but the source enters failure mode and stops transmitting content
Solution Approach 1:
The system performs preliminary testing by sequentially reading sets of test KSVs with different numbers before actual content transmission. This preliminary action determines the maximum KSV capacity of the source, preventing future transmission failures by ensuring the system operates within supported limits.
2Adaptability or versatility
If the HDCP source is configured to support a high number of KSVs, then more sinks can be connected, but the source may not actually support that many and will fail
Solution Approach 1:
The HDCP source automatically determines its own KSV capacity through the sequential testing process. The system self-configures by reading test KSVs and identifying its maximum supported number without requiring manual configuration or complex external setup, making the system easy to operate while adapting to its actual capabilities.
3Device complexity
If the system does not determine the source's actual KSV support, then configuration is simpler, but transmission failures occur undetected
Solution Approach 1:
The system implements feedback by monitoring whether the source enters failure mode when reading different numbers of KSVs. This feedback mechanism allows the system to automatically detect the maximum supported KSV count and adjust configuration accordingly, making transmission failures detectable and preventable without increasing overall system complexity.
Data Source
AI summary
Presented is a method for determining the maximum number of key selection vectors (KSVs) supported by an HDCP source. The method includes providing a number of KSVs to the HDCP source, determining whether the HDCP source has entered a failure mode in response to the provided number of KSVs, increasing or decreasing the number of KSVs in response to the HDCP source not entering or entering the failure mode, providing the increased or decreased number of KSVs to the HDCP source, determining whether the HDCP source has entered the failure mode in response to the provided increased or decreased number of KSVs, and repeating the increasing, decreasing, and determining steps until the difference between a lowest number of provided KSVs resulting in the HDCP source entering the failure mode and a highest number of provided KSVs resulting in the HDCP source not entering the failure mode is one.