Guided In-Loop Filtering for Video Ringing Artifact Reduction
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Solution Overview
Problem
Existing video coding technologies struggle to effectively remove ringing artifacts caused by transform and quantization processes, which are not adequately addressed by current in-loop filters.
Innovation Solution
The implementation of a guided filter that applies statistical computations to reconstructed video samples within a defined window, adjusting sample values using weighted means to mitigate ringing artifacts, and can be applied at various stages of the in-loop filtering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If in-loop filters are applied to remove artifacts, then video quality is improved, but ringing artifacts caused by transform and quantization are not adequately removed
Solution Approach 1:
The patent introduces a guided filter as an intermediary processing step between the transform/quantization stages and the final reconstruction. This filter uses guidance from the original block to modify the reconstructed block, effectively mediating the artifact removal process without directly altering the core transform/quantization operations that cause the ringing artifacts.
Solution Approach 2:
The patent modifies the reconstruction process by applying a guided filter that adjusts pixel values based on statistical computations (mean, variance) within local windows. This changes the parameters of the reconstructed block by blending original and reconstructed values with adaptive weights, thereby reducing ringing artifacts while preserving edge details.
2Object-generated harmful factors
If filtering operations are applied to reconstructed samples, then ringing artifacts are reduced, but computational complexity increases
Solution Approach 1:
The patent divides the filtering operation into manageable segments by processing the video block in sub-blocks or regions. The guided filter is applied locally to specific regions where ringing artifacts are most prominent, rather than uniformly across the entire block, thereby reducing overall computational complexity while maintaining effectiveness.
Solution Approach 2:
The patent applies the guided filter selectively rather than universally - using it partially only where needed (e.g., in regions with high-frequency content or visible artifacts) rather than applying full filtering strength across all areas. This partial action approach reduces computational burden while still achieving the desired artifact reduction.
Data Source
AI summary
A mechanism for processing video data is disclosed. A conversion is performed between a visual media data including a video unit and a bitstream. The conversion can be performed by a video encoder and/or a video decoder. The video unit is reconstructed. and a guided filter is applied to reconstructed samples in the video unit.