Adaptive Deblocking Filter for Non-Square Coding Units
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Solution Overview
Problem
The existing deblocking filters in video coding standards like H.265/HEVC, designed for square coding units, are inefficient for non-square coding units introduced by the quadtree plus binary tree (QTBT) structure, leading to suboptimal compression performance and visual artifacts.
Innovation Solution
An adaptive deblocking filter selection mechanism that determines the shape of coding units and applies appropriate filters based on their shapes, selecting from a range of filters with different tap amounts and coefficient values to improve compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a deblocking filter designed for square CUs is applied to non-square CUs, then the filter structure remains simple, but compression performance deteriorates and visual artifacts increase
Solution Approach 1:
The patent implements dynamic filter selection based on CU shape. The system determines whether each CU is square or non-square and selectively applies different deblocking filter configurations accordingly. This dynamic adaptation allows the filter to optimize for compression performance on non-square CUs while maintaining simplicity on square CUs, resolving the contradiction between filter design simplicity and compression performance.
2Productivity
If an adaptive deblocking filter selection mechanism is implemented, then compression performance improves, but device complexity increases
Solution Approach 1:
The patent changes the parameter being filtered (CU shape characteristics) to select appropriate filter configurations. By analyzing the geometric parameters of CUs and adapting filter strength and type accordingly, the system achieves improved compression efficiency without requiring complex multi-dimensional filter banks, thus managing device complexity while improving productivity.
3Productivity
If multiple filter types with different tap amounts are used, then visual quality improves, but processing complexity increases
Solution Approach 1:
The patent applies local quality by using different filter tap amounts and coefficients for different CU shapes and boundary locations. Non-square CUs receive different filtering treatment compared to square CUs, and boundaries between different CU types receive specialized handling. This localized adaptation improves visual quality by addressing specific artifact patterns in different regions without requiring complex global processing.
Data Source
AI summary
Systems and methods are provided for selecting and applying an appropriate deblocking filter for improved coding efficiency and compression performance by partitioning a frame into a plurality of rectangular coding units (CUs) according to the QTBT frame partitioning scheme, selecting a first and a second CUs of the plurality of rectangular CUs, where the second CU is adjacent to the first CU, identifying a CU boundary shared by the first and second CUs, determining that at least one of the first or the second CU is non-square in shape, determining a first shape of the first CU and a second shape of the second CU, adaptively selecting a deblocking filter based on the first shape and the second shape, and applying the selected deblocking filter to pixels across the CU boundary.