IPCM Video Coding Deblocking Filter Strength Control

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Solution Overview

Problem

Current video coding techniques face challenges in improving visual quality, particularly in deblocking filtering for intra pulse code modulation (IPCM) and lossless coding modes, where existing methods often result in inadequate deblocking filtering strength or incorrect filtering decisions, leading to suboptimal visual outcomes.

Innovation Solution

The proposed techniques involve assigning a non-zero quantization parameter (QP) value for IPCM coded blocks based on signaled, predicted, or delta QP values, and disabling deblocking filtering for losslessly coded blocks, while performing deblocking filtering in a specific manner for adjacent blocks, to enhance visual quality by optimizing filtering strength and decision-making.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If deblocking filtering is applied to IPCM coded blocks, then visual quality at block boundaries is improved, but filtering strength may be insufficient leading to residual blocking artifacts

Engineering Contradiction:
Improvevisual qualityVSAvoidfiltering strength
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the quantization parameter QP from its traditional role as a compression control to actively control deblocking filter strength. By deriving QP for IPCM blocks based on neighboring blocks rather than using fixed or zero values, the filter strength is dynamically adjusted to match the visual characteristics of adjacent regions, resolving the contradiction between applying filtering and achieving sufficient filtering strength.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If deblocking filtering is applied to losslessly coded blocks, then boundary continuity may be improved, but original lossless data integrity is compromised

Engineering Contradiction:
Improveboundary continuityVSAvoiddata integrity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies different deblocking filtering strategies to different block types based on their local characteristics. Losslessly coded blocks have deblocking disabled to preserve their perfect reconstruction property, while IPCM and lossy blocks receive appropriate filtering. This local differentiation resolves the contradiction by maintaining data integrity where required while achieving boundary continuity where applicable.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If deblocking filtering is performed on blocks adjacent to IPCM or lossless blocks, then visual quality at interfaces is improved, but incorrect filtering decisions may degrade overall quality

Engineering Contradiction:
Improvevisual qualityVSAvoidfiltering decision accuracy
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses feedback from neighboring blocks to determine the appropriate deblocking filter strength for IPCM and lossless blocks. By deriving QP values based on adjacent blocks' characteristics and using this information to guide filtering decisions, the system achieves accurate filtering that adapts to local conditions, resolving the contradiction between improving interface quality and avoiding incorrect filtering decisions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2988504B1Intra pulse code modulation (IPCM) and lossless coding mode deblocking for video coding
Publication Date: 2021.12.08 QUALCOMM INC
  • EP2988504B1 patent drawingFigure 1
  • EP2988504B1 patent drawingFigure 2
  • EP2988504B1 patent drawingFigure 3

AI summary

Techniques for coding video data include coding a plurality of blocks of video data, wherein at least one block of the plurality of blocks of video data is coded using a coding mode that is one of an intra pulse code modulation (IPCM) coding mode and a lossless coding mode. In some examples, the lossless coding mode may use prediction. The techniques further include assigning a non-zero quantization parameter (QP) value for the at least one block coded using the coding mode. The techniques also include performing deblocking filtering on one or more of the plurality of blocks of video data based on the coding mode used to code the at least one block and the assigned non-zero QP value for the at least one block.