Video Parameter Set Coding with OLS-Adaptive PTL Signaling
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Solution Overview
Problem
Existing video coding standards face inefficiencies in signaling Video Parameter Set (VPS) and Sequence Parameter Set (SPS) structures, leading to increased signaling overhead and reduced coding efficiency due to inconsistent and redundant signaling methods for Profile, Tier, and Level (PTL) syntax structures, Decoded Picture Buffer (DPB) parameters, and Hypothetical Reference Decoder (HRD) parameters across different Output Layer Sets (OLSs).
Innovation Solution
The proposed method involves determining equalities between the number of PTL, DPB, and HRD syntax structures and OLSs, allowing for the omission of redundant index signaling and the use of variable-length coding for PTL syntax elements, thereby optimizing the bitstream signaling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If index signaling is used for PTL syntax structures in VPS, then the signaling can handle cases with unequal numbers of PTL structures and OLSs, but the signaling overhead increases when the numbers are equal
Solution Approach 1:
The patent applies local quality by making the PTL syntax structure signaling adaptive to the specific case: when the number of PTL structures equals the number of OLSs, no index signaling is performed (simpler approach), but when they are unequal, index signaling is performed (more complex approach). This localized adaptation optimizes signaling overhead for each specific scenario while maintaining the ability to handle both cases.
2Ease of operation
If fixed-length coding is used for PTL syntax elements, then the decoding is simpler and more predictable, but the bitstream size increases
Solution Approach 1:
The patent changes the coding parameter from fixed-length to variable-length coding for PTL syntax elements. This allows the bitstream size to adapt to the actual information content, reducing redundancy while maintaining decoding capability through proper syntax definitions and context in the bitstream.
3Adaptability or versatility
If redundant PTL syntax structures are signaled for each OLS, then each OLS can have independent PTL parameters, but the signaling overhead and processing complexity increase
Solution Approach 1:
The patent merges the PTL syntax structure signaling by allowing a single PTL structure to apply to multiple OLSs when they share the same PTL parameters. This is achieved by not signaling an index when the number of PTL structures equals the number of OLSs, effectively combining the signaling for multiple OLSs into a single shared definition, thereby reducing overhead and complexity.
Solution Approach 2:
The patent implements universality by making PTL syntax structures applicable to multiple OLSs simultaneously. A single PTL structure can serve as the PTL configuration for multiple output layer sets, allowing the same PTL parameters to be universally applied across different OLSs, which reduces redundancy while maintaining the capability for independent PTL configuration when needed.
Data Source
AI summary
The present disclosure provides a computer-implemented method for encoding video. The method includes: determining whether a coded video sequence (CVS) contains equal number of profile, tier and level (PTL) syntax structures and output layer sets (OLSs); and in response to the CVS containing equal number of PTL syntax structures and OLSs, coding the bitstream without signaling a first PTL syntax element specifying an index, to a list of PTL syntax structures in the VPS, of a PTL syntax structure that applies to a corresponding OLS in the VPS.