Video Coding Chroma Prediction with Luminance Residual Mapping
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Solution Overview
Problem
Existing video coding standards like H.266 prioritize luminance blocks over chrominance blocks in inter coding, leading to inefficiencies in chrominance-specific tools and reduced effectiveness of cross-component prediction methods.
Innovation Solution
A method is introduced to directly map luminance residuals into chrominance prediction, using co-located reference areas and motion-compensated prediction to enhance cross-component residual modeling, applicable in single-tree and dual-tree blocks, with additional methods to improve robustness and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-tree motion compensated prediction is used with shared partitioning between luminance and chrominance, then device complexity is reduced, but chrominance prediction effectiveness deteriorates
Solution Approach 1:
The patent segments the prediction process into separate luminance and chrominance prediction paths within the single-tree framework. By deriving chroma-specific model parameters independently from co-located chroma blocks and applying them through dedicated mapping functions, the chrominance prediction is segmented from the luminance prediction, allowing both components to benefit from the shared partitioning structure while maintaining independent optimization for chroma quality.
2Productivity
If luminance blocks are prioritized in inter coding, then coding efficiency for luminance is improved, but chrominance-specific tools become less effective
Solution Approach 1:
The patent applies local quality by deriving chroma-specific model parameters from co-located chroma blocks and applying them through dedicated mapping functions. This allows the chrominance components to receive localized optimization tailored to their specific characteristics, while the overall single-tree framework maintains luminance prioritization for coding efficiency. The local chroma prediction models ensure that chrominance-specific tools remain effective despite the shared partitioning structure.
3Manufacturing precision
If cross-component prediction models are applied in single-tree inter blocks, then chrominance prediction is improved, but the disparity between luminance and chrominance coding remains
Solution Approach 1:
The patent implements dynamics by making the chroma prediction model adaptive through derivation from co-located chroma blocks and application through flexible mapping functions. The model parameters are dynamically adjusted based on the specific chroma block characteristics and co-located reference data, allowing the system to adapt to different content types and coding scenarios while maintaining improved chrominance prediction quality within the single-tree framework.
Data Source
AI summary
A method comprising receiving an image block unit of a frame, the image block unit comprising samples in a first chrominance channel, chrominance channel, a second chrominance channel and one luminance channel; defining co-located reference areas over luminance components of the luminance channel, chroma components of the first chrominance channel and chroma components of the second chrominance channel; performing motion-compensated prediction for the luminance component, the first chrominance component and the second chrominance component using reference frames and motion vectors; obtaining a first mapping function that maps the luminance component into the first chrominance component and a second mapping function that maps the luminance component into the second chrominance component using the co-located luminance prediction and the chrominance predictions; reconstructing a luminance residual; and obtaining a first chrominance prediction by using the first function and the luminance residual, and a second chrominance prediction by using the second function and the luminance residual; and obtaining a first chrominance prediction by using the first function and the luminance residual, a second chrominance prediction by using the second function and the luminance residual.