Adaptive Deblocking Filter for Video Coding Using Block-Size Clipping

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Solution Overview

Problem

Existing video coding technologies struggle to effectively reduce blockiness artifacts in reconstructed video frames, particularly with larger block sizes, while maintaining computational efficiency and coding quality.

Innovation Solution

A deblocking filtering technique that adapts to the location and size of reconstructed video blocks, applying clipping values to modify samples based on the amount of modification caused by filtering, thereby reducing blockiness artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If deblocking filtering is applied to remove blockiness artifacts, then video quality is improved, but computational complexity increases

Engineering Contradiction:
Improvevideo qualityVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies different filtering operations to different regions based on block size: strong filtering for small blocks (4x4, 8x8) and clipping-based filtering for large blocks (16x16, 32x32, 64x64). This local differentiation improves video quality where needed while reducing computational complexity for large blocks where simple clipping suffices.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the filtering parameter based on block size. For large blocks, it uses clipping values (tbOffset, tcOffset) derived from quantization parameters and boundary strengths, rather than applying full deblocking filters. This parameter adaptation reduces computational load while maintaining quality improvement.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If clipping values are applied to modify samples, then blockiness artifacts are reduced, but distortion may be introduced

Engineering Contradiction:
Improveartifact reductionVSAvoidsample accuracy
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies clipping operations that prevent excessive modification of samples. By using clipping values to limit the range of sample adjustments, it preemptively prevents distortion while still removing blockiness artifacts. The clipping bounds ensure samples remain within acceptable ranges.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent applies partial filtering action through clipping rather than full deblocking. For large blocks, it uses clipping values to make limited adjustments to boundary samples, which is sufficient to reduce artifacts without introducing the excessive modification that would cause distortion.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If filter strength is increased for large blocks, then distortion removal is improved, but processing time increases

Engineering Contradiction:
Improvedistortion removalVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent segments the filtering approach by block size. It divides blocks into small (4x4, 8x8) and large (16x16, 32x32, 64x64) categories, applying different filtering strategies to each segment. This segmentation allows efficient processing of large blocks through clipping while maintaining strong filtering for smaller blocks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically selects the filtering method based on block size. Rather than applying a fixed filter strength to all blocks, it adapts the filtering approach: strong deblocking for small blocks and clipping-based filtering for large blocks. This dynamic adaptation optimizes processing time while maintaining distortion removal effectiveness.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3844958B1Deblocking filter for video coding and processing
Publication Date: 2026.02.18 QUALCOMM INC
  • EP3844958B1 patent drawingFigure 1
  • EP3844958B1 patent drawingFigure 2A~2B
  • EP3844958B1 patent drawingFigure 3

AI summary

A video decoder configured to obtain a first reconstructed block of video data that includes a first sample with a first value; apply deblocking filtering to the first reconstructed block to create a deblocking filtered block; determine a first clipping value for the first sample based on a location of the first sample relative to a boundary of the reconstructed block and based on a size of the reconstructed block; compare the first clipping value to an amount of modification to the first sample caused by the deblocking filtering; in response to the amount of modification to the first sample caused by the deblocking filtering being greater than the first clipping value, modify the first value by the first clipping value to determine a first filtered value for the first sample; and output a deblocking filtered block of video data with the first sample having the first filtered value.