Deblocking Filter Boundary Strength for Video Coding

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Solution Overview

Problem

Existing video coding technologies face challenges in reducing visual artifacts caused by block-based coding, particularly at the edges between video blocks, which affect the quality of decoded video data.

Innovation Solution

A deblocking filter is applied to the edges between video blocks based on specific boundary strength values, depending on whether the blocks are intra-predicted or not, and additional conditions, to reduce the visibility of blocking artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If deblocking filters are applied to all edges between video blocks, then blocking artifacts are reduced, but processing complexity increases

Engineering Contradiction:
Improveblocking artifactsVSAvoidfiltering complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies different boundary strength values (0, 1, or 2) to different edges based on local characteristics such as intra-prediction mode and block type. This selective approach ensures filtering is applied only where needed, reducing overall processing complexity while maintaining artifact reduction effectiveness in critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of boundary strength (Bs) to control filtering intensity dynamically. By setting Bs=0 to disable filtering, Bs=1 for weak filtering, and Bs=2 for strong filtering, the system adapts the filtering strength to local edge characteristics, optimizing the balance between artifact reduction and processing load.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If boundary strength is increased for all edges, then artifact reduction is improved, but processing time increases

Engineering Contradiction:
Improvevisual artifactsVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent determines boundary strength locally for each edge based on specific conditions: Bs=2 when either block is intra-predicted, Bs=1 when blocks are inter-predicted with certain conditions, and Bs=0 otherwise. This localized assessment prevents unnecessary processing time on edges that don't require strong filtering.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial filtering action by setting Bs=0 for edges that don't meet specific criteria, effectively skipping filtering for those edges. This selective partial action reduces processing time while maintaining sufficient artifact reduction for edges that genuinely need it.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3975557A1Determining boundary strength values for deblocking filtering for video coding
Publication Date: 2022.03.30 QUALCOMM INC
  • EP3975557A1 patent drawingFigure 1
  • EP3975557A1 patent drawingFigure 2
  • EP3975557A1 patent drawingFigure 3

AI summary

A video coder associates a first boundary strength value with an edge in response to determining that a first video block or a second video block is associated with an intra-predicted coding unit (CU), where the edge occurs at a boundary between the first video block and the second video block. The video coder may associate a second or a third boundary strength value with the edge when neither the first video block nor the second video block is associated with an intra-predicted CU. The video coder may apply one or more deblocking filters to samples associated with the edge when the edge is associated with the first boundary strength value or the second boundary strength value. The third boundary strength value indicates that the deblocking filters are turned off for the samples associated with the edge.