Cross-Component Adaptive Loop Filter Coefficient Constraint
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Solution Overview
Problem
The dynamic range of intermedia data during the filtering process in cross-component adaptive loop filters (CC-ALF) for video coding exceeds 16-bit, which is undesirable, especially for software implementation, and existing solutions do not effectively constrain the range of CC-ALF filter coefficients.
Innovation Solution
Constraining the CC-ALF filter coefficients to be less than the sum of the bit-depth value associated with the luma samples and a positive offset value, ensuring the dynamic range remains within a preferred limit, such as 16-bit, by using a cross-component adaptive loop filter that refines the chroma component based on extracted luma samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cross-component adaptive loop filter (CC-ALF) is used to refine chroma component based on luma samples, then filtering quality is improved, but the dynamic range of intermedia data exceeds 16-bit which complicates software implementation
Solution Approach 1:
The patent constrains the CC-ALF filter coefficients to a specific range (less than the sum of bit-depth value and positive offset value) to ensure the dynamic range of intermedia data remains within 16-bit. This parameter constraint allows standard 16-bit fixed-point arithmetic to be used in software implementation, avoiding the need for more complex data types while maintaining filtering quality.
2Adaptability or versatility
If CC-ALF coefficients are not constrained, then filtering flexibility is improved, but encoding and decoding efficiency deteriorates due to increased dynamic range requirements
Solution Approach 1:
By constraining CC-ALF coefficients to be less than the sum of bit-depth value and positive offset value, the patent maintains sufficient filtering flexibility while ensuring the dynamic range fits within 16-bit. This enables efficient fixed-point arithmetic operations during encoding and decoding, improving processing speed and reducing computational overhead compared to unconstrained coefficient ranges.
Data Source
AI summary
A method, computer program, and computer system is provided for video coding. Video data comprising a chroma component and a luma component is received. Luma samples are extracted from the luma component of the received video data. The chroma component is filtered based on the extracted luma samples using a cross-component adaptive loop filter (CC-ALF). Coefficients associated with the CC-ALF are constrained to be less than a sum of a bit-depth value associated with the luma samples and a positive offset value.