Cross-Component Loop Filtering for Chroma Refinement in Video Coding
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Solution Overview
Problem
Existing video coding technologies lack an efficient mechanism for encoding and decoding chroma and luma components of an image frame while maintaining image quality, particularly in the context of cross-component adaptive loop filtering.
Innovation Solution
Implement a cross-component adaptive loop filter (CC-ALF) that refines chroma components based on surrounding chroma components and adjacent luma components, using an anchor luma component to form difference luma components for refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cross-component adaptive loop filter is applied to refine chroma components using luma components, then coding efficiency and image quality are enhanced, but computational complexity and processing overhead increase
Solution Approach 1:
The patent applies different filtering operations to different components (luma and chroma) based on their specific characteristics. The cross-component filter selectively uses luma components to refine chroma components only where beneficial, rather than applying uniform filtering across all components. This localized approach maintains image quality while reducing unnecessary computational overhead.
Solution Approach 2:
The filtering process is segmented into distinct stages: first applying adaptive loop filtering to luma and chroma components separately, then applying cross-component filtering to refine chroma using luma. This segmentation allows each filtering operation to be optimized independently, balancing quality improvement with computational complexity management.
2Productivity
If cross-component adaptive loop filter is applied to refine chroma components, then video compression performance is improved, but processing time and computational resources increase
Solution Approach 1:
The patent performs adaptive loop filtering on luma and chroma components as preliminary processing before applying the cross-component filter. By preparing the components in advance and organizing them in a reference picture buffer, the subsequent cross-component filtering operation can proceed more efficiently, reducing overall processing time while maintaining compression performance.
3Adaptability or versatility
If adaptive loop filtering is applied separately to luma and chroma components, then component-specific optimization is achieved, but overall filtering efficiency is reduced
Solution Approach 1:
The patent merges the separate adaptive loop filtering operations with a cross-component filtering operation. After independently filtering luma and chroma components, the cross-component filter combines information from both components to refine chroma further. This merging approach maintains the benefits of component-specific optimization while improving overall filtering efficiency through coordinated processing.
Data Source
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AI summary
This application is directed to processing video data that includes a plurality of luma samples and a plurality of chroma samples corresponding to a plurality of pixel groups of a video frame. For each pixel group, an electronic device identifies a respective chroma sample and a set of luma samples and determines an anchor luma sample from the set of luma samples. A chroma refinement value is generated based on the set of luma samples by differencing a respective luminance value of each luma sample in the set by an anchor luminance value of the anchor luma sample and applying a cross component filter to the difference luminance values of the set of luma samples. The electronic device then updates the chroma sample using the chroma refinement value for each pixel group and stores the updated respective chroma sample of each pixel group in association with the video frame.