Strong Intra Smoothing Chroma Format Restrictions
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Solution Overview
Problem
In high efficiency video coding, there is a mismatch in handling Strong Intra Smoothing (SIS) for chroma in 4:4:4 chroma format, leading to degradation in coding performance and introduction of blocking artifacts.
Innovation Solution
Restrictions are applied to enable or disable SIS based on specific conditions, preventing its application for chroma when the chroma format is 4:4:4, and implementing filtering processes for neighboring samples to optimize encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SIS is applied to chroma in 4:4:4 format, then intra prediction smoothing is improved, but coding efficiency is degraded and blocking artifacts are introduced
Solution Approach 1:
The patent applies different smoothing rules to different chroma formats: 4:2:0 format receives strong intra smoothing (SIS) while 4:4:4 format receives disabled SIS. This local differentiation resolves the contradiction by enabling smoothing benefits for formats that need it while preventing the harmful blocking artifacts that occur in 4:4:4 format.
2Object-affected harmful factors
If SIS is enabled for chroma in 4:4:4 format, then visual artifact reduction is improved, but encoding performance becomes inconsistent with reference software
Solution Approach 1:
The patent changes the operational parameter of SIS based on chroma format: it is enabled for 4:2:0 but disabled for 4:4:4. This parameter change ensures consistent encoding behavior with reference software implementations while still providing visual artifact reduction where appropriate.
Data Source
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AI summary
Based on conditions or restrictions, Strong Intra Smoothing (SIS) is enabled or disabled. SIS is not allowed for chroma when the chroma format is 444, and SIS is not allowed for chroma when the chroma format is 422 or 444.