Shared Level Signaling for Scalable Video Coding
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Solution Overview
Problem
Current video coding standards, such as H.264 and HEVC, face inefficiencies in level signaling for layered video coding, leading to redundant transmission of sequence and picture parameter sets, increased codeword lengths, and computational resource misalignment, which affect decoding capabilities and coding efficiency.
Innovation Solution
The proposed solution allows all layers in a bitstream to share the same level ID, enabling the use of a single sequence parameter set across layers, with sub-bitstream level indicators providing additional constraints, and signaling profile and level information in SEI messages to optimize decoding capabilities and reduce redundant parameter sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sequence parameter sets are used for each layer to indicate different level requirements, then decoding capability accuracy is improved, but bitstream redundancy and complexity increase
Solution Approach 1:
The patent merges the level indication functionality from multiple separate sequence parameter sets into a single shared sequence parameter set. All layers reference the same SPS containing a level indicator that represents the maximum level across all layers, eliminating redundant parameter sets while maintaining decoding capability accuracy through the sub-bitstream level indicator mechanism.
Solution Approach 2:
The shared sequence parameter set serves multiple layers simultaneously, providing universal level indication for the entire bitstream. The level indicator in the shared SPS universally applies to all layers that reference it, while sub-bitstream level indicators provide layer-specific constraints when needed, enabling one parameter set to fulfill multiple indication functions.
2Reliability
If separate sequence parameter sets are transmitted for each layer, then layer-specific decoding requirements are met, but transmission efficiency decreases
Solution Approach 1:
The patent combines level indication information from multiple layers into a single shared sequence parameter set, reducing the total number of parameter sets that need to be transmitted. This merging approach maintains reliability by preserving layer-specific requirements through sub-bitstream level indicators while improving transmission efficiency by eliminating redundant data.
Solution Approach 2:
The patent extracts layer-specific level requirements from the shared sequence parameter set and places them in sub-bitstream level indicators. This extraction allows the main SPS to remain compact and shared across layers, while specific layer requirements are separately indicated only where necessary, optimizing both transmission efficiency and decoding accuracy.
3Adaptability or versatility
If higher level IDs are assigned to accommodate all layers in the SPS, then decoder capability coverage is improved, but computational resource alignment deteriorates
Solution Approach 1:
The patent applies different level indication qualities to different layers: the shared SPS contains a level indicator that provides broad decoder capability coverage for all layers, while sub-bitstream level indicators provide precise local level constraints for individual layers. This local quality approach ensures that each layer receives the appropriate level of specificity without forcing all layers to use the highest level ID.
Solution Approach 2:
The patent changes the semantics of level indicators by introducing sub-bitstream level indicators that operate at a different parameter level than the shared SPS level indicator. The shared SPS level indicator uses higher level IDs for broad coverage, while sub-bitstream indicators use lower, more precise level values for specific layers, allowing parameter optimization at different hierarchical levels.
Data Source
AI summary
Techniques to determine a level id in a layered bitstream are disclosed, such that the same level id can be used for all layers of a scalable bitstream. Also disclosed are techniques to signal level ids for sub bitstreams that can be indicative of lower computational requirements than the level id used for the layered bitstream.