Chroma Deblocking Filter for Video Artifacts

Solution Overview

Problem

Block-based video coding standards like H.261, H.262, H.263, H.264/AVC, and MPEG series suffer from visible artifacts known as blocking artifacts due to the block-based prediction and residual signal coding, which affect the quality of reconstructed images.

Innovation Solution

A method for video decoding that applies a de-blocking filter on the boundaries between chroma blocks, specifically considering if at least one block is intra-coded or part of a collection with non-zero transform coefficients, to reduce these artifacts, using simplified criteria and tables for chroma deblocking filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If block-based prediction and residual signal coding are used, then data compression is achieved, but blocking artifacts appear in reconstructed images

Engineering Contradiction:

Improvedata compression ratioVSAvoidblocking artifacts

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies deblocking filtering selectively based on local block characteristics. The filter is applied to chroma blocks where at least one block is intra-coded or where blocks have non-zero transform coefficients, while avoiding filtering in other regions. This local adaptation reduces blocking artifacts where they occur most while maintaining compression efficiency elsewhere.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the filtering parameters based on chroma block characteristics. The deblocking filter strength and application are adjusted according to whether blocks are intra-coded or have non-zero transform coefficients, optimizing the balance between artifact reduction and compression performance.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If deblocking filtering is applied to all chroma blocks, then blocking artifacts are reduced, but decoding complexity increases

Engineering Contradiction:

Improveblocking artifactsVSAvoiddecoding complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies deblocking filtering selectively based on local block characteristics. The filter is applied to chroma blocks where at least one block is intra-coded or where blocks have non-zero transform coefficients, while avoiding filtering in other regions. This local adaptation reduces blocking artifacts where they occur most while maintaining compression efficiency elsewhere.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies deblocking filtering partially - only to chroma blocks that meet specific criteria (intra-coded or non-zero transform coefficients) rather than all chroma blocks. This partial application reduces decoding complexity while still addressing the blocking artifacts in the most problematic regions.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If simplified deblocking criteria are used for chroma blocks, then decoding speed is improved, but filtering accuracy may be reduced

Engineering Contradiction:

Improvedecoding speedVSAvoidfiltering accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies deblocking filtering partially - only to chroma blocks that meet specific criteria (intra-coded or non-zero transform coefficients) rather than all chroma blocks. This partial application reduces decoding complexity while still addressing the blocking artifacts in the most problematic regions.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7822125B2Method for chroma deblocking

Publication Date: 2010.10.26 CISCO TECHNOLOGY INC

AI summary

The invention is related to decoding of block wise coded video pictures. The determination of using de-blocking filtering between coded chroma blocks is based on alternative characteristics compared to the characteristics used in H.264/AVC.