Transform Coefficient Coding Using a Single Adaptive Context Function
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In block-based image and video codecs, the increasing demand for high compression rates while maintaining low complexity is challenging due to variable transform block sizes and the need to convey additional data like depth maps, which requires multiple contexts and symbolization schemes to accurately adapt to coefficient statistics.
Innovation Solution
An apparatus and method that use a context-adaptive entropy decoder and symbolizer to decode and encode transform coefficients, employing a single function for context selection and symbolization parameter determination, which is parameterizable based on previously coded/decoded coefficients, to efficiently handle different block sizes and information types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple contexts and symbolization schemes are used to adapt to coefficient statistics for high compression rates, then coding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by using a single parameterizable function with adjustable parameters to determine both contexts and symbolization schemes. Instead of maintaining multiple fixed functions, the system changes the parameters of one function adaptively based on previously coded coefficients, achieving high coding efficiency while reducing the complexity of managing multiple separate contexts and schemes.
2Device complexity
If a single parameterizable function is used for context selection and symbolization parameter determination, then device complexity is reduced, but adaptability to different block sizes and information types decreases
Solution Approach 1:
The patent implements universality by designing a single function that serves multiple purposes: it selects contexts for entropy decoding and determines symbolization schemes simultaneously. This multi-functional approach allows the system to handle different block sizes and information types (luma, chroma, depth maps) through parameter adjustment rather than requiring separate dedicated functions for each case.
Solution Approach 2:
The system applies dynamics by making the function parameters adaptive rather than fixed. The parameters are dynamically adjusted based on previously coded coefficients, allowing the single function to adapt its behavior to different block sizes, frequency regions, and information types, thereby maintaining versatility without requiring multiple static functions.
3Ease of operation
If proprietary logic overhead is reduced by using a unified approach, then ease of operation is improved, but measurement precision of coefficient statistics decreases
Solution Approach 1:
The patent implements feedback mechanisms where the determination of contexts and symbolization schemes relies on previously coded coefficients. This feedback loop allows the system to continuously adapt to the actual statistics of the transform coefficients being coded, maintaining measurement precision while using a unified approach that reduces proprietary logic overhead and simplifies operation.
Data Source
AI summary
An idea used herein is to use the same function for the dependency of the context and the dependency of the symbolization parameter on previously coded/decoded transform coefficients. Using the same function—with varying function parameter—may even be used with respect to different transform block sizes and/or frequency portions of the transform blocks in case of the transform coefficients being spatially arranged in transform blocks. A further variant of this idea is to use the same function for the dependency of a symbolization parameter on previously coded/decoded transform coefficients for different sizes of the current transform coefficient's transform block, different information component types of the current transform coefficient's transform block and/or different frequency portions the current transform coefficient is located within the transform block.