Selective Adaptive Color-Space Transform for VVC Tool Compatibility
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Solution Overview
Problem
The interaction between adaptive color-space transform (ACT) and other tools in video coding, particularly in the Versatile Video Coding (VVC) standard, needs to be resolved to enhance compression efficiency and simplify implementations.
Innovation Solution
The use of adaptive color-space transform (ACT) is managed through enabling or disabling based on the presence of dual tree partitioning, in-loop reshaping (ILR), and other coding tools, with specific rules for CU and TU levels, ensuring compatibility and efficient conversion between color domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adaptive color-space transform (ACT) tool is used for video coding, then compression efficiency is improved, but device complexity increases due to additional color domain conversion operations
Solution Approach 1:
The patent applies ACT selectively at the transform unit level rather than uniformly across the entire video block. By determining ACT applicability for each TU individually based on local characteristics, the system improves compression efficiency in regions where ACT is beneficial while avoiding unnecessary complexity in regions where it is not needed, thus resolving the contradiction between compression efficiency and device complexity.
2Productivity
If ACT tool is enabled for all video blocks, then compression performance is improved, but implementation complexity increases due to additional conversion operations between color domains
Solution Approach 1:
Instead of applying ACT to all video blocks (excessive action), the patent implements partial action by determining ACT applicability on a per-TU basis. The system performs color domain conversion only for TUs where ACT is determined to be applicable, thereby achieving compression performance improvement without the full implementation complexity of universal ACT application.
3Productivity
If dual tree partitioning structure is used for video coding, then compression efficiency is improved, but ACT tool usage becomes restricted due to structural constraints
Solution Approach 1:
The patent segments the video block into multiple TUs and independently determines ACT applicability for each TU even when dual tree partitioning is used. This segmentation approach allows ACT to be applied selectively within the constrained dual tree structure, maintaining compression efficiency while preserving some degree of ACT tool usage flexibility within the structural constraints.
Data Source
AI summary
A method of video processing is provided. The method includes: determining, for a conversion between a current video unit of a video and a coded representation of the video, that applicability of a first coding tool and a second coding tool is mutually exclusive; and performing the conversion based on the determining, wherein the first coding tool corresponds to an adaptive color space transformation (ACT) tool; wherein use of the ACT tool comprises: converting, during encoding, a representation of a visual signal from a first color domain to a second color domain, or converting, during decoding, a representation of a visual signal from the second color domain to the first color domain.