Unified CCB Counting for Transform Skip Residual Coding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in managing context-coded bins (CCB) for transform residual and transform skip residual modes, leading to suboptimal compression efficiency due to differing CCB count mechanisms in High Efficiency Video Coding (HEVC) and Versatile Video Coding (VVC) standards.
Innovation Solution
A unified approach is introduced to limit the number of context-coded bins (CCB) by applying a consistent bound for both transform residual and transform skip residual coding processes, adjusting entropy coding methods based on the counted CCBs, and optimizing the syntax elements in video encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different CCB count mechanisms are used for transform residual and transform skip residual modes, then each mode can be optimized independently, but the overall system complexity increases and compression efficiency deteriorates
Solution Approach 1:
The patent merges the CCB count management of transform residual mode and transform skip residual mode into a unified mechanism. Both modes now share the same CCB bound calculation and entropy coding adjustment logic, eliminating the need for separate management mechanisms while maintaining mode-specific coding optimizations through the unified framework
Solution Approach 2:
The unified CCB bound is designed to serve multiple functions: it limits context-coded bins for both transform residual and transform skip residual modes, provides a common basis for entropy coding method adjustments, and enables consistent rate-distortion optimization across different residual coding modes
2Productivity
If separate entropy coding methods are used for transform residual and transform skip residual modes, then each mode achieves optimal coding performance, but the decoding complexity and processing overhead increase
Solution Approach 1:
The patent introduces dynamic adjustment of entropy coding methods based on the unified CCB count. The entropy coding approach (context-coded vs. bypass-coded) is dynamically selected based on the current CCB consumption state, allowing the system to adapt the coding complexity to the actual residual characteristics while maintaining a unified management framework
3Device complexity
If a unified CCB bound is applied to both transform residual and transform skip residual modes, then system complexity is reduced and management is simplified, but the ability to optimize each mode independently may be limited
Solution Approach 1:
While the CCB bound management is unified, the patent preserves local optimization capabilities by allowing different entropy coding adjustments and syntax element treatments for transform residual and transform skip residual modes based on their specific characteristics, ensuring that each mode can be optimized for its particular residual patterns
Data Source
AI summary
In one implementation, the CCB counting methods are unified between the transform residual coding process and Transform Skip (TS) residual coding process. In one example, in TS residual coding, the CCB counting excludes the coeff_sign_flag so that syntax used for CCB count is unified for the two residual coding processes. In addition, a separate maximum number of context coded bins can be specified and used for coeff_sign_flag only. In another example, in TS residual coding, the maximum number of CCB count is reduced from TB_size*2 for a TB to TB_size*1.75, or more generally both the maximum CCB counts of the transform residual coding and TS residual coding are set to an identical value, so that the maximum CCB count is unified for the two residual coding processes.