Adaptive Deblocking Filter Length for Video Coding Artifacts
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Solution Overview
Problem
Block-based video compression leads to visible discontinuities at block boundaries, known as block artifacts, which existing deblocking methods struggle to effectively address.
Innovation Solution
A deblocking filtering method that determines whether to apply a filter set based on inter-side and intra-side differences, filter lengths, and continuity thresholds, using adaptive filtering to reduce block artifacts by selecting from a set of candidate filters with varying tap lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block-based video compression is used to achieve efficient video coding, then productivity is improved, but block artifacts appear causing video quality to deteriorate
Solution Approach 1:
The deblocking filter applies different filtering strengths to different regions along the block boundary based on local characteristics. The filter selectively processes samples where block artifacts are present while leaving other regions unchanged, achieving localized quality improvement without affecting the entire video frame.
Solution Approach 2:
The filter dynamically adjusts its operation parameters (filtering strength, tap length) based on the detected characteristics of the block boundary samples. By changing filtering parameters adaptively rather than applying a fixed filter, the system maintains coding efficiency while reducing block artifacts.
2Object-affected harmful factors
If strong filtering is applied to reduce block artifacts, then video quality is improved, but filtering complexity increases
Solution Approach 1:
The deblocking filter transitions from static filtering to dynamic adaptive filtering. The filter's behavior changes based on real-time analysis of sample characteristics at the block boundary, adjusting its strength and scope to match the actual artifact severity, thereby reducing unnecessary filtering operations.
Solution Approach 2:
The block boundary is divided into multiple segments or regions, and the filter is applied selectively to specific segments where artifacts are detected. This segmentation approach reduces the overall filtering complexity by processing only the necessary portions rather than the entire boundary.
3Device complexity
If fixed filter length is used to simplify the filtering process, then device complexity is reduced, but adaptability to different boundary characteristics deteriorates
Solution Approach 1:
The filter length changes dynamically based on the characteristics of the block boundary samples. The system selects from multiple predefined filter lengths (e.g., 2-tap, 4-tap, 6-tap) depending on the detected artifact severity and sample variance, achieving adaptability without requiring complex real-time filter design.
Solution Approach 2:
The filter applies varying degrees of filtering action to different parts of the block boundary. By using multiple filter lengths, the system can apply stronger filtering where needed and weaker or no filtering where unnecessary, optimizing the balance between complexity and adaptability.
Data Source
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Figure 3A~3B
AI summary
A deblocking filtering method includes receiving reconstructed video data associated with a block boundary in a video coding system. The block boundary has N lines of samples crossing the block boundary from a P side to a Q side of the boundary. The method further includes determining whether to apply a first filter set to reduce block artifacts at the block boundary based on whether a first inter-side difference of a first line of the N lines of samples is greater than an inter-side difference threshold, determining a filter length of a filter in the first filter set based on a first side length of the P side, and a second side length of the Q side when it is determined to apply the first filter set, and applying at least one filter in the first filter set with the determined filter length on the block boundary.