Image Decoding Device Layer Integrity Bit Stream Extraction
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Solution Overview
Problem
Conventional techniques face issues where parameter sets on lower layers are discarded during bit stream extraction, leading to incomplete decoding of higher layers, resulting in layers that cannot be decoded.
Innovation Solution
An image decoding apparatus that extracts image-coded data based on a target layer ID list and highest temporal ID, discarding NAL units with layer IDs not in the list or temporal IDs greater than the highest temporal ID, and sets non-VCL NAL units' layer IDs to the lowest layer ID in the list to ensure complete decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bit stream extraction is performed by discarding NAL units with layer IDs not in the target layer ID list, then data transmission efficiency is improved, but parameter sets on lower layers may be discarded leading to incomplete decoding of higher layers
Solution Approach 1:
The patent applies preliminary action by determining the minimum layer ID required for decoding higher layers before performing bit stream extraction. The extraction process is designed to preserve parameter sets from lower layers that are needed as reference for inter-layer prediction, ensuring that decoding can proceed correctly without requiring subsequent retrieval of discarded parameter sets.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a layer dependency relationship determination process. This intermediary step identifies which lower layer parameter sets are required by higher layers, acting as a mediator between the extraction process and the decoding process to ensure that necessary parameter sets are retained while unnecessary ones are discarded.
2Reliability
If all NAL units are retained in the bit stream, then decoding reliability is maintained, but data transmission efficiency deteriorates due to redundant data
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting which NAL units are retained or discarded based on layer dependency relationships. The extraction process uses parameters such as target layer ID list and minimum layer ID to determine the optimal subset of NAL units to keep, changing the composition of the bit stream to balance reliability and efficiency based on the specific decoding requirements.
3Measurement precision
If parameter sets from lower layers are preserved for inter-layer prediction, then decoding accuracy is improved, but data redundancy increases
Solution Approach 1:
The patent applies local quality by selectively preserving parameter sets from lower layers only where they are needed for inter-layer prediction. Rather than uniformly retaining all lower layer parameter sets, the extraction process identifies specific parameter sets that have local dependency relationships with higher layers and preserves only those, reducing overall redundancy while maintaining necessary decoding accuracy.
Data Source
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AI summary
A layer incapable of being decoded on a bit stream which is generated through a bit stream extraction process from a bit stream including a prescribed layer set and which only includes a layer set made up of a subset of the prescribed layer set, occurs. An aspect of the present invention specifies a bit stream constraint pertaining to a parameter set, and a bit stream extraction process.