Deblocking Filter Strength for IntraBC Video Coding

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Solution Overview

Problem

The existing deblocking filter processes in High Efficiency Video Coding (HEVC) systems, particularly for Intra-block copy (IntraBC) mode, do not effectively address the visual quality issues around block boundaries, leading to suboptimal results.

Innovation Solution

A method and apparatus for determining and applying a boundary filter strength of one or zero to block boundaries involving IntraBC coded blocks, based on coding parameters such as reference picture lists, motion vectors, and block vector differences, to improve deblocking filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the existing deblocking filter process is used for IntraBC mode, then the processing is simple, but the visual quality around block boundaries deteriorates

Engineering Contradiction:
Improvesimplicity of deblocking filter processVSAvoidvisual quality issues around block boundaries
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies different boundary filter strength rules specifically at block boundaries involving IntraBC coded blocks, while maintaining standard processing for other blocks. This local differentiation addresses the visual quality issues at IntraBC boundaries without complicating the overall deblocking filter process.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the boundary filter strength parameter selection based on the coding mode of neighboring blocks. When an IntraBC coded block is detected, specific rules are applied to select boundary filter strength values of one or zero, optimizing the filtering effect for IntraBC boundaries while maintaining simplicity.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If stronger deblocking filtering is applied to IntraBC blocks, then visual quality improves, but bit-rate increases

Engineering Contradiction:
Improvevisual quality around block boundariesVSAvoidbit-rate
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent optimizes the boundary filter strength parameter selection for IntraBC blocks by applying specific rules that select values of one or zero based on coding parameters. This optimized parameter selection improves visual quality while avoiding excessive filtering that would increase bit-rate, achieving up to 2.9% RD-Rate reduction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses coding parameters such as reference picture lists, motion vectors, and block vector differences as feedback to determine the appropriate boundary filter strength. This feedback mechanism allows the deblocking filter to adaptively select optimal filtering strength, improving visual quality while controlling bit-rate increase.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If boundary filter strength is increased for IntraBC blocks, then artifacts around block boundaries are reduced, but processing complexity increases

Engineering Contradiction:
Improveartifacts around block boundariesVSAvoiddeblocking filter processing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies enhanced boundary filter strength rules specifically to IntraBC coded blocks while maintaining standard processing for other blocks. This localized approach reduces artifacts at IntraBC boundaries without increasing the complexity of the overall deblocking filter processing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the boundary filter strength parameter selection based on detected IntraBC coding mode, using coding parameters to determine when to apply stronger filtering. This parameter-based approach systematically reduces artifacts without requiring complex processing logic.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3178228B1Method of deblocking for intra block copy in video coding
Publication Date: 2023.10.04 HFI INNOVATION INC
  • EP3178228B1 patent drawingFigure 1A
  • EP3178228B1 patent drawingFigure 1B
  • EP3178228B1 patent drawingFigure 2~3

AI summary

A method and apparatus for applying deblocking filter to block boundaries in a video coding system including an IntraBC (Intra-block copy) mode are disclosed. According to the present invention, for at least one combination of the two neighboring reconstructed blocks including at least one IntraBC coded block in the two neighboring reconstructed blocks, a boundary filter strength equal to one or zero is selected based on coding parameters associated with the two neighboring reconstructed blocks. Deblocking filter is then applied to neighboring samples of the two neighboring reconstructed blocks around the block boundary using the boundary filter strength selected. For example, when the two neighboring reconstructed blocks correspond to one IntraBC coded block and one Inter coded block, the boundary filter strength is set to one.