HEVC Context Decoding With Selective Neighbor Block References
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Solution Overview
Problem
In image coding and decoding methods, particularly in High-Efficiency Video Coding (HEVC), the memory usage is high due to the reliance on context models that use neighboring blocks, leading to increased memory requirements and inefficiencies in arithmetic coding and decoding processes.
Innovation Solution
The proposed method determines contexts for image blocks based on signal types, using neighboring blocks for certain types and omitting the use of the upper block's control parameter for specific types like 'split_coding_unit_flag' and 'cbf_luma', thereby reducing memory usage and processing amounts by selecting appropriate contexts for hierarchical tree structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If context models using neighboring blocks are used for all signal types, then coding accuracy is improved, but memory usage increases
Solution Approach 1:
The patent applies different context determination strategies to different signal types based on their local characteristics. For split_coding_unit_flag and skip_flag, only the left block's context is used. For cbf_luma, cbf_cb, and cbf_cr, neither upper nor left block contexts are used. This localized differentiation resolves the contradiction by optimizing memory usage for each specific signal type while maintaining coding accuracy where needed.
2Productivity
If decoded control parameters of neighboring blocks are used for context determination, then arithmetic coding efficiency is improved, but processing complexity increases
Solution Approach 1:
The patent implements localized context determination rules for different control parameter types. By specifying that split_coding_unit_flag and skip_flag use only left block context, while cbf parameters use no neighboring context, the patent reduces processing complexity for parameter determination while maintaining arithmetic coding efficiency through appropriate context selection for each signal type.
3Measurement precision
If upper block context is used for all signal types, then prediction accuracy is improved, but memory reference amount increases
Solution Approach 1:
The patent applies selective context usage based on signal type characteristics. For split_coding_unit_flag and skip_flag, only left block context is referenced. For cbf parameters, no neighboring block context is used. This localized approach reduces memory reference amounts while maintaining prediction accuracy for signal types where upper block context would be beneficial.
Data Source
AI summary
The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type, and the second type is one of “cbf_luma”, “cbf_cb”, and “cbf_cr”.