Slice Header State Flag for Flexible Picture Header Decoding
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Solution Overview
Problem
The existing solutions for merging picture and slice headers in video coding standards like JVET-Q0255 and JVET-Q0426 face issues such as unnecessary bit usage, lack of support for multiple slices per picture, and unclear detection of picture boundaries, which impact efficiency and compliance in video decoding.
Innovation Solution
Introduce a state syntax element in the slice header to indicate the presence or absence of a picture header, allowing flexible handling of slice structures without requiring additional NAL unit types or syntax elements, enabling efficient decoding and compliance checking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional NAL unit types are introduced to indicate picture header presence, then the decoding process can handle mixed access units, but the device complexity and bitstream overhead increase
Solution Approach 1:
The patent merges the picture header presence indication with the existing slice header structure by using a flag within the slice header syntax. This combines multiple functions (slice identification and picture header presence indication) into a single existing structure, avoiding the need for separate NAL unit types while maintaining decoding flexibility
Solution Approach 2:
The slice header structure is enhanced to serve multiple purposes: it identifies slices within pictures and simultaneously indicates the presence or absence of picture headers. This multi-functional approach allows the same syntax element to handle both traditional slice identification and the new requirement for picture header presence indication without increasing NAL unit type complexity
2Adaptability or versatility
If a state syntax element is added to the slice header to indicate picture header presence, then bit cost increases due to additional syntax elements, but decoding flexibility is improved
Solution Approach 1:
The patent implements a dynamic syntax structure where the presence of additional syntax elements in the slice header is conditional. The picture header presence flag is only present when needed (when access units without picture headers are used), allowing the bitstream to adapt its structure based on the specific encoding requirements, thereby minimizing unnecessary bit cost while maintaining flexibility
3Reliability
If picture headers are mandatory for all access units, then decoding compliance is simplified, but the ability to support efficient coding formats without picture headers is limited
Solution Approach 1:
The patent applies local quality by allowing different parts of the bitstream to have different structures. Some access units can include picture headers while others can omit them, with the slice header providing the necessary indication. This localized approach maintains decoding compliance through clear syntax rules while supporting diverse coding formats with varying efficiency requirements
Data Source
AI summary
A method for decoding a picture from a bitstream. In one embodiment, The method includes: receiving a slice header for a slice of the picture, wherein the slice header comprises a state syntax element; decoding a state value from the state syntax element in the slice header, wherein a) if the state value is not equal to a first value, then the state value indicates that i) the bitstream includes for the picture a picture header comprising a set of picture syntax elements and ii) the slice header does not comprise the set of picture syntax elements and b) if the state value is equal to the first value, then the state value indicates that i) the slice header contains said set of picture syntax elements and ii) the bitstream does not include a picture header for the picture; and using the set of picture syntax elements to decode the slice of the picture.