Chroma Block Decoding With Nonlinear Luma-Based Prediction Filters

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Solution Overview

Problem

Existing video coding techniques rely on inadequate linear model equations for predicting chroma blocks, leading to inefficient decoding and low prediction accuracy.

Innovation Solution

A method and device for predicting chroma blocks using non-linear model filters based on luma blocks, involving gradient filters and down-sampling to generate luma square and gradient values, which are applied to prediction model filters with filter parameters determined by neighboring samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If linear model equations are used for predicting chroma blocks, then the decoding process is simple, but the prediction accuracy is insufficient

Engineering Contradiction:
Improvedecoding simplicityVSAvoidprediction accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the prediction model from a simple linear equation to a quadratic model by changing the mathematical parameters. The quadratic prediction model uses luma gradient values and luma square values as new parameters, enabling more accurate chroma prediction while maintaining computational efficiency through the structured approach of calculating gradients and applying quadratic equations.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If only linear model equations are used, then the decoding efficiency is maintained, but the prediction precision for all block units is inadequate

Engineering Contradiction:
Improvedecoding efficiencyVSAvoidprediction precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces quadratic parameters (luma gradient values and luma square values) to enhance prediction precision while maintaining decoding efficiency. The structured calculation process for gradients and the systematic application of quadratic models ensure that the increased precision does not come at the cost of excessive computational complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the prediction process into distinct stages: calculating luma gradient values, calculating luma square values, and applying the quadratic prediction model. This segmentation allows each component to be optimized independently, maintaining overall decoding efficiency while achieving superior prediction precision through the combination of these specialized sub-processes.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If multiple non-linear model filters are implemented, then the prediction accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidmodel filter complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent focuses on implementing a quadratic prediction model with specific parameters (luma gradient values and luma square values) rather than exploring multiple complex non-linear models. This targeted approach to parameter changes achieves high prediction accuracy while controlling device complexity by concentrating on one well-defined mathematical framework rather than managing multiple diverse non-linear models.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4354859B1Device and method for decoding video data
Publication Date: 2025.12.03 SHARP KK
  • EP4354859B1 patent drawingFigure 1
  • EP4354859B1 patent drawingFigure 2
  • EP4354859B1 patent drawingFigure 3

AI summary

A method of decoding video data performed by an electronic device is provided. The method receives the video data and determines a block unit from a current frame included in the video data. The method further determines a plurality of luma reconstructed samples in a luma block of the block unit based on the video data and determines a prediction model filter of a prediction model mode for a chroma block of the block unit based on the video data. The method then determines a prediction model filter of a prediction model mode for a chroma block of the block unit based on the video data and reconstruct the chroma block of the block unit by applying the plurality of luma square values and the plurality of luma gradient values to the prediction model filter.