Video Encoder Verification Using Safe-Partitioned Decode Comparison
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Solution Overview
Problem
Existing video encoding and decoding systems, particularly those using codecs like H.264/AVC and H.265/HEVC, are complex and lack effective methods to verify compliance with safety regulations such as IEC 61508, EN 50128, and EN 50657, making them vulnerable to safety hazards in critical applications.
Innovation Solution
A method for verifying video data in an encoder unit is implemented by disabling loop filtering, using a safe part to compare encoded data with acquired data through deterministic algorithms, and generating safety sequences like checksums or signatures to ensure compliance with safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If complex video compression algorithms (H.264/AVC, H.265/HEVC) are used to reduce network bandwidth, then transmission efficiency is improved, but verification of safety compliance becomes difficult and system reliability deteriorates
Solution Approach 1:
The encoder is divided into a safe part and a non-safe part. The safe part handles video acquisition and verification functions, while the non-safe part handles complex encoding operations. This segmentation allows the system to use complex compression algorithms while maintaining a verified safe component for safety-critical functions.
Solution Approach 2:
A safety sequence (checksum or signature) is introduced as an intermediary verification mechanism. The safe part generates this safety sequence based on acquired video data, and the decoded video data is verified against it. This intermediary enables safety verification without requiring the entire encoding system to be safety-qualified.
2Manufacturing precision
If loop filtering is enabled in the encoder, then video quality is improved, but verification complexity increases and deterministic behavior becomes difficult to achieve
Solution Approach 1:
Loop filtering is removed from the safe part of the encoder. The safe part performs video acquisition and generates safety sequences without applying loop filtering. This extraction allows the safe part to maintain deterministic, verifiable behavior while the overall system can still produce high-quality video through the non-safe encoding portion.
3Reliability
If safety-qualified components are extensively developed to meet standards like IEC 61508 and EN 50128, then system reliability is improved, but device complexity and development effort increase significantly
Solution Approach 1:
The encoder is segmented into safe and non-safe parts, where only the safe part (handling acquisition and verification) needs to be safety-qualified. This segmentation dramatically reduces the amount of code and functionality that requires extensive safety certification processes while still enabling compliance with standards like IEC 61508 and EN 50128.
Solution Approach 2:
Instead of verifying the entire complex encoding process, the invention copies the essential verification function into the safe part by generating safety sequences that represent the expected output. This copying approach simplifies verification to comparing against a predetermined safety sequence rather than verifying the entire encoding chain.
4Reliability
If deterministic comparison algorithms are used to verify decoded video data, then safety verification reliability is improved, but processing time increases
Solution Approach 1:
The verification process uses partial action by comparing only essential features represented in the safety sequence rather than performing exhaustive frame-by-frame pixel comparison. This partial verification approach maintains high reliability for safety-critical checks while reducing processing time compared to complete video data verification.
Data Source
AI summary
The present application relates to a method for verifying video data encoded in an encoder unit, wherein the encoder unit comprises a safe part and a non-safe part, wherein loop filtering in the encoder unit is disabled, and wherein the method (1) comprises the steps of:Acquiring video data in the safe part of the encoder unit (2,11,21);Encoding the acquired video data by a non-safe encoder in the non-safe part of the encoder unit (3,12,22);Decoding the encoded video data by a non-safe decoder in the non-safe part of the encoder unit (4,13,23); andComparing the decoded video data with the acquired video data in the safe part of the encoder unit using at least one comparison algorithm (5,14,24), wherein if the decoded video data does not match the acquired video data exactly nor within an acceptable threshold for the comparison a safety focused reaction is initiated, and if the decoded video data matches the acquired video data exactly or within the acceptable threshold for the comparison a first safety sequence is generated based on the decoded video data in the safe part of the encoder unit and the encoded video data and the first safety sequence are transmitted to a decoder unit for decoding the encoded video data.