Deblocking Filter Controller for Weighted Bi-Prediction Discontinuity
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Solution Overview
Problem
In video encoding and decoding, especially with VVC, weighted bi-prediction can lead to discontinuity between blocks due to different weighted coefficients, resulting in visual deterioration even when motion vector and reference image match is high.
Innovation Solution
An encoding and decoding device that includes a deblocking filter controller, which adjusts the deblocking filter based on weighted coefficients applied to blocks, ensuring appropriate filtering to mitigate discontinuity and improve image quality and encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weighted bi-prediction is applied to blocks with different weighted coefficients, then prediction accuracy is improved, but discontinuity between blocks increases leading to visual deterioration
Solution Approach 1:
The patent changes the parameter of the deblocking filter based on the weighted coefficients used in bi-prediction. When different weighted coefficients are applied to adjacent blocks, the filter strength is increased to compensate for the discontinuity. This resolves the contradiction by adjusting the filtering parameter dynamically according to the prediction parameters, maintaining both prediction accuracy and visual quality.
2Object-affected harmful factors
If deblocking filter is applied to block boundaries, then visual quality is improved, but encoding complexity increases
Solution Approach 1:
The patent applies the deblocking filter selectively based on local conditions - specifically, whether different weighted coefficients are used in bi-prediction for adjacent blocks. The filter is applied only where needed (at boundaries of blocks with different weighted coefficients) rather than uniformly across all block boundaries. This resolves the contradiction by making the filtering process adaptive and localized, improving visual quality only where discontinuity occurs while minimizing overall encoding complexity.
Data Source
AI summary
An encoding device that performs encoding on each of blocks obtained by dividing an image includes: a weighted bi-predictor 181a configured to generate a prediction block of an encoding-target block by weighted-averaging a plurality of reference images using weighted coefficients selected from a weighted coefficient set including a plurality of weighted coefficients; and a filter controller 161 configured to control deblocking filter based on the weighted coefficients applied by the weighted bi-predictor 181a to each of the two blocks adjacent blocks.