CCSAO Filter Offset Reuse for Luma-Chroma Coding Efficiency
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Solution Overview
Problem
Existing video coding standards face challenges in efficiently encoding and decoding high-definition and ultra-high-definition video data while maintaining image quality, particularly in optimizing the coding efficiency of luma and chroma components.
Innovation Solution
The implementation of Cross-Component Sample Adaptive Offset (CCSAO) filter, which utilizes cross-component correlation to enhance the coding efficiency by applying filter offset sets based on the relationship between luma and chroma components, including classifiers that use luma samples to determine chroma sample offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional video coding standards are used for high-definition and ultra-high-definition video, then video data can be encoded and decoded, but coding efficiency is insufficient and image quality deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the Sample Adaptive Offset (SAO) filtering process to use cross-component correlations between luma and chroma components. Instead of treating components independently, the invention changes the filtering parameters to utilize inter-component relationships, thereby improving coding efficiency while maintaining or enhancing image quality for high-definition and ultra-high-definition video
Solution Approach 2:
The patent introduces an intermediary mechanism where luma component samples serve as a mediator to improve chroma component coding. By using luma samples to derive chroma offset values through cross-component correlation, the system achieves better chroma coding efficiency without requiring additional chroma reference data, thus resolving the contradiction between coding efficiency and image quality
2Productivity
If luma and chroma components are coded independently, then coding process is simple, but coding efficiency is suboptimal
Solution Approach 1:
The patent changes the coding approach from independent component coding to correlated component coding by modifying the SAO filtering parameters. The invention uses cross-component correlation to derive chroma offset values based on luma samples, improving coding efficiency while adding minimal complexity to the coding process
Solution Approach 2:
The patent applies universality by making the luma component serve multiple functions: it is used for its own coding and also as a reference for chroma component coding through cross-component correlation. This multi-functional use of luma samples improves overall coding efficiency without requiring separate processing for each component, thus balancing efficiency gains with acceptable complexity
Data Source
AI summary
An electronic apparatus performs a method of decoding video data. The method includes: receiving, from the video data, an Adaptation Parameter Set (APS) identifier associated with a number of previously used Cross-Component Sample Adaptive Offset (CCSAO) filter offset sets stored in APS; receiving, from the video data, a syntax in Picture Header (PH) or Slice Header (SH) that indicates the APS identifier used for a current picture or slice; decoding, for the current coding tree unit (CTU), a filter set index that indicates a particular previously used CCSAO filter offset set of the number of offset sets in the APS associated with the APS identifier; and applying the particular previously used CCSAO filter offset set to the current CTU of the video data.