Sub-Block Residual Coding in Transform Skip Mode
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in transform skip mode and sub-block transform (SBT) due to explicit signaling of split direction, position, and non-zero coefficients, which consume significant bandwidth and are disallowed in certain modes.
Innovation Solution
Implement a method to split video blocks into sub-blocks with non-zero coefficients, using implicit derivation of split patterns and coefficients based on spatial and temporal gradients, and adaptively applying SBT in transform skip mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explicit signaling of split direction, position, and non-zero coefficients is used in transform skip mode and sub-block transform, then the transform can be applied, but bandwidth consumption increases significantly
Solution Approach 1:
The patent extracts only the necessary information for transform application by using implicit derivation rules based on gradient calculations. Instead of signaling all split parameters explicitly, the system calculates gradients and derives split patterns and non-zero coefficient positions implicitly, removing redundant signaling data from the bitstream while maintaining transform functionality.
Solution Approach 2:
The system enables self-service by allowing the decoder to automatically determine split patterns and non-zero coefficient positions through gradient-based implicit derivation. The decoder calculates spatial and temporal gradients itself and uses predefined rules to identify which sub-blocks contain non-zero coefficients, eliminating the need for explicit signaling of this information.
2Reliability
If explicit signaling of split direction, position, and non-zero coefficients is used, then transform skip mode can function, but device complexity increases
Solution Approach 1:
The decoder performs self-service by automatically deriving split patterns and non-zero coefficient positions through gradient calculations and predefined derivation rules. This eliminates complex signaling mechanisms and reduces device complexity while maintaining full transform skip mode functionality.
Solution Approach 2:
The patent changes the parameter representation from explicit signaling values to implicit gradient-based derivations. By using gradient magnitude and direction as the basis for determining split patterns and non-zero coefficient positions, the system transforms complex signaling parameters into simpler gradient calculations that reduce overall device complexity.
3Manufacturing precision
If sub-blocks are split and processed individually, then coding precision improves, but processing time increases
Solution Approach 1:
The patent applies segmentation by dividing the video block into sub-blocks for individual processing, which improves coding precision by allowing different transform characteristics for different regions. The gradient-based implicit derivation efficiently identifies which sub-blocks need processing, reducing the overall processing time compared to processing all sub-blocks uniformly.
Solution Approach 2:
The system performs partial action by processing only the sub-blocks that contain non-zero coefficients, as determined by implicit gradient-based derivation. This avoids unnecessary processing of sub-blocks that would not contribute to coding precision, thereby reducing processing time while maintaining the benefits of sub-block processing where needed.
Data Source
AI summary
A method for video processing includes determining, based on a first indication, whether a sub-block residual coding scheme is applied to residual of a current video block in a transform skip mode, the sub-block residual coding scheme splitting the residual of the current video block into multiple sub-blocks and a subset of the multiple sub-blocks have non-zero coefficients; determining, based on a second indication, a specific split pattern to be applied to the residual of the current video block, in response to the sub-block residual coding scheme being applied to the residual of the current video block; deriving, based on a third indication, the subset of the multiple sub-blocks which have non-zero coefficients; and performing a conversion on the residue of the current video block based on the determined subset of sub-blocks having non-zero coefficients.