Cross-Component Adaptive Loop Filtering Using Luma Samples
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Solution Overview
Problem
Existing video coding technologies lack an efficient mechanism for refining chroma components of video frames based on surrounding luma components, leading to suboptimal image quality in decoded video data.
Innovation Solution
Implement a cross component adaptive loop filter that refines chroma samples using a set of adjacent luma samples, determined by an anchor luma sample within a predefined anchoring rule, to enhance the coding efficiency and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cross component adaptive loop filter is applied to refine chroma components using luma samples, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary mechanism that uses luma samples as a mediator to refine chroma components. Instead of directly processing chroma samples, the system uses luma samples as an intermediate reference to generate refined chroma values, thereby improving image quality while managing computational complexity through cross-component utilization
Solution Approach 2:
The luma samples serve multiple functions: they are used both for luma reconstruction and as reference data for chroma refinement. This multi-functionality allows the system to improve chroma component quality without requiring separate dedicated reference data, effectively managing the complexity-improvement tradeoff
2Productivity
If adaptive loop filter is applied to chroma and luma components, then coding efficiency is improved, but processing time increases
Solution Approach 1:
The system performs preliminary actions by pre-determining the set of luma samples that will be used for chroma refinement based on anchoring rules. This preliminary identification of reference samples allows for more efficient processing during the actual filtering operation, as the reference data is already selected and prepared, reducing the time required during chroma refinement
Solution Approach 2:
The patent applies local quality by selectively using luma samples based on their spatial relationship with chroma samples through anchoring rules. Not all luma samples are used uniformly, but rather those locally relevant to each chroma sample's position, optimizing the balance between coding efficiency and processing time through localized processing
Data Source
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 according to a predefined rule. A chroma refinement value is generated based on the set of luma samples by: obtaining a difference between a respective luminance value of each luma sample in the set and an anchor luminance value of the anchor luma sample, applying a cross component filter to the differences-luminance values of the set of luma samples to obtain a cross component filtering result, and performing a non-linear clipping operation based on the cross component filtering result. The electronic device derives a value of the respective chroma sample using the chroma refinement value.