Quantization Matrix Modeling via Four-Parameter Optimization

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Solution Overview

Problem

Conventional methods for designing quantization matrices in video codecs are computationally expensive and oversimplify the quantization matrix space due to their reliance on few parameters, which affects the optimization of video/image quality.

Innovation Solution

A method that generates and optimizes quantization matrices using a symmetric quadratic model with four parameters, allowing for automatic optimization of encoding parameters to maximize video/image quality, employing numerical search methods and quality metrics like PSNR and VQM.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional methods use a three-parameter model to reduce the dimension of quantization matrix from 16 or 64 coefficients to 3 parameters, then the computational complexity is reduced, but the model oversimplifies the quantization matrix space and cannot achieve optimal video quality

Engineering Contradiction:
Improvecomputational complexityVSAvoidquantization matrix optimization precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the number of parameters from 3 to 4 in the quadratic model, which fundamentally alters the model's capability to represent quantization matrices. This parameter change enables the model to capture more complex relationships in the quantization space while maintaining computational efficiency through the closed-form solution of the quadratic optimization problem.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional methods perform search in a 64-dimensional or 16-dimensional space of optimal coefficient sets, then the optimization precision can be improved, but the computational cost becomes prohibitive

Engineering Contradiction:
Improvequantization matrix optimization precisionVSAvoidencoding speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent transforms the high-dimensional search problem into a low-dimensional parameter optimization problem by changing from 64 or 16 coefficients to only 4 parameters. This parameter reduction makes the optimization computationally tractable while preserving the essential characteristics of optimal quantization matrices through the quadratic model's ability to capture frequency-dependent weighting patterns.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8326068B1Method and apparatus for modeling quantization matrices for image/video encoding
Publication Date: 2012.12.04 GEO SEMICONDUCTOR INC
  • US8326068B1 patent drawing
  • US8326068B1 patent drawing
  • US8326068B1 patent drawing

AI summary

A method for encoding an image is disclosed. The method generally includes the steps, of (A) generating a quantization matrix as a function of at least four parameters, (B) optimizing the parameters to maximize a quality metric for encoding the image and (C) encoding the image with the quantization matrix as optimized.