HRD Parameter Syntax Structure for Video Bitstream Efficiency
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Solution Overview
Problem
Existing video coding standards face inefficiencies in signaling Hypothetical Reference Decoder (HRD) parameters, particularly in allowing common information to be shared across multiple operation points and efficiently encoding layer identifiers, which can lead to increased complexity and reduced bit rate efficiency.
Innovation Solution
The proposed solution involves explicitly signaling common HRD parameters for any HRD parameter syntax structure and allowing one SEI message to be applied to multiple operation points, using layer identification information in the NAL unit header to determine applicable operation points, and optimizing the coding of layer identifiers through differential coding or flag usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If common HRD parameters are signaled for each HRD parameter syntax structure individually, then completeness of parameter information is improved, but signaling redundancy increases and bit rate efficiency deteriorates
Solution Approach 1:
The patent merges common HRD parameters across multiple HRD parameter syntax structures by introducing a syntax element that indicates whether parameters are common. When the syntax element value indicates common parameters, the decoder reuses parameters from a reference syntax structure, combining the information from multiple structures into a unified parameter set and eliminating redundant signaling.
Solution Approach 2:
The patent makes HRD parameters universal across different operation points and sub-layers by allowing a single set of common parameters to serve multiple HRD parameter syntax structures. The syntax element mechanism enables parameters to function both as structure-specific parameters when needed and as common parameters when applicable, achieving multi-functionality.
2Measurement precision
If layer identifiers are explicitly coded for each operation point, then precision of operation point identification is improved, but coding complexity and bit rate increase
Solution Approach 1:
The patent changes the coding parameter for layer identifiers from explicit full-value coding to differential coding. Instead of signaling the complete layer identifier value, the system signals the difference from a reference value, reducing the number of bits required while maintaining precise identification capability through the differential value.
Solution Approach 2:
The patent uses copying by referencing previously signaled layer identifier values as defaults for subsequent operation points. When layer identifiers are identical across multiple operation points, the system copies the reference value rather than re-signaling it, reducing redundancy while preserving accurate identification.
3Adaptability or versatility
If multiple SEI messages are used to cover different operation points, then applicability to diverse operation points is improved, but message overhead and processing burden increase
Solution Approach 1:
The patent makes SEI messages universal by enabling a single SEI message to apply to multiple operation points through the common HRD parameters mechanism. The syntax element indicating common parameters allows one SEI message to serve multiple operation points simultaneously, eliminating the need for separate messages for each operation point.
Solution Approach 2:
The patent merges multiple SEI messages that would otherwise be needed for different operation points into a single unified SEI message when common HRD parameters are applicable. This combining reduces the total number of messages from multiple separate messages to one consolidated message while maintaining full applicability.
Data Source
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AI summary
A video encoder signals, in an encoded video bitstream, a video parameter set (VPS) that includes a plurality of Hypothetical Reference Decoder (HRD) parameter syntax structures that each include HRD parameters. For each respective HRD parameter syntax structure in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters in addition to a set of sub-layer-specific HRD parameter information specific to a particular sub-layer of the encoded video bitstream. The common set of HRD parameters is common to all sub-layers of the encoded video bitstream. A video decoder or other device decodes, from the encoded video bitstream, the VPS and performs an operation using the HRD parameters of at least one of the HRD parameter syntax structures.