4:2:2 Chroma Deblocking Filters for Reduced Block Artifacts

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Solution Overview

Problem

Existing video coding standards face challenges in effectively addressing block artifacts in reconstructed video data, particularly for chroma components, which can degrade video quality.

Innovation Solution

A method and device for deblocking reconstructed video data, involving the computation of gradient values at vertical deblocking boundaries for chroma components and modifying filter parameters based on adjacent sample values to reduce blockiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If deblocking filters are applied to reconstructed video data, then block artifacts are reduced and video quality is improved, but computational complexity and processing time increase

Engineering Contradiction:

Improvevideo qualityVSAvoidcomputational complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The deblocking filter is divided into multiple processing stages: gradient computation stage, parameter modification stage, and filtering stage. Each stage processes specific portions of the video data independently, allowing for optimized computation and reduced overall complexity while maintaining video quality improvements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The filter parameters are modified locally based on gradient values computed at specific deblocking boundaries. Rather than applying uniform filtering across all boundaries, the system adapts filter strength and characteristics to local image characteristics, reducing unnecessary computation in regions where blocking artifacts are minimal while maintaining effectiveness where needed.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If gradient computation is performed using multiple lines for deblocking decision, then filtering accuracy is improved, but processing time increases

Engineering Contradiction:

Improvefiltering accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system computes gradient values using a selective subset of lines rather than all available lines. For vertical deblocking boundaries, gradients are computed using lines adjacent to the boundary, and for horizontal boundaries, gradients use corresponding horizontal lines. This partial computation approach provides sufficient filtering accuracy while significantly reducing processing time compared to using all lines.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

Gradient values are computed in advance during the reconstruction process, before the actual deblocking filtering is applied. This preliminary computation allows the filtering stage to use pre-calculated gradient information, improving filtering accuracy while avoiding the time cost of real-time gradient computation during the filtering operation itself.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12407838B2Systems and methods for applying deblocking filters to reconstructed video data

Publication Date: 2025.09.02 SHARP KK

AI summary

This disclosure relates to video coding and more particularly to techniques for performing deblocking of reconstructed video data. According to an aspect of an invention, reconstructed video data having a 4:2:2 chroma format is received and for a four line decision segment corresponding to a vertical deblocking boundary for a chroma component of the video data, a gradient value is computed using samples included in the first and fourth lines.