VVC Picture and Slice Header Syntax for Lower-Complexity Decoding
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Solution Overview
Problem
The changes in the high-level syntax structure of the Versatile Video Coding (VVC) standard have increased complexity without a corresponding improvement in coding performance, necessitating a reduction in complexity without degrading coding performance.
Innovation Solution
Implementing constraints in the bitstream syntax by ensuring that certain information is signaled only in the picture header or slice header, not both, thereby simplifying decoding and encoding processes and reducing redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If information is signaled in both picture header and slice header, then flexibility and adaptability are improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent implements dynamic syntax element signaling where the presence of certain syntax elements in the slice header is controlled by a flag (e.g., `slice_header_extension_present_flag`) that can be set based on specific conditions. This allows the bitstream structure to adapt dynamically - including extended syntax elements when needed and excluding them when not needed, thereby maintaining flexibility while controlling complexity through conditional signaling rather than always-present elements.
Solution Approach 2:
The patent applies local quality by allowing different slices within the same picture to have different header structures. Each slice can independently include or exclude extended syntax elements based on its specific requirements, rather than forcing all slices to have the same comprehensive header structure. This localized approach reduces overall complexity while maintaining adaptability where needed.
2Reliability
If all possible syntax elements are always included in headers, then reliability and completeness are improved, but loss of information (redundancy) increases
Solution Approach 1:
The patent implements partial action by including only the necessary subset of syntax elements in each slice header rather than all possible elements. The `slice_header_extension_present_flag` enables selective inclusion of extended syntax elements only when required by specific coding conditions, avoiding the redundancy of always including every possible element even when not needed.
Solution Approach 2:
The patent segments the header structure into mandatory base elements and optional extended elements. The base picture header and slice header contain essential syntax elements that are always present, while extended syntax elements are separated into optional sections that are included only when specific conditions are met, reducing redundancy while maintaining completeness when needed.
Data Source
AI summary
A method of decoding video data from a bitstream, the bitstream comprising video data corresponding to one or more slices. The bitstream comprises a picture header comprising syntax elements to be used when decoding one or more slices, and a slice header comprising syntax elements to be used when decoding a slice. The decoding comprises in a case where information which can be signalled in the picture header or in the slice header is signalled in the picture header, a picture header is to be signalled in a slice header, permitting parsing of information which may otherwise be signalled in a slice header and a picture header, in only one of the slice header or picture header; imposing that the picture header is not in the slice header, and decoding said bitstream using said syntax elements.