Chroma Quantization Correction for Transform-Skipped Image Encoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image encoding methods, such as HEVC and VVC, face inefficiencies in encoding artificial images due to unnecessary increases in code amount when using quantization parameters less than 4, leading to suboptimal image quality and increased data size.
Innovation Solution
Adaptive correction of quantization parameters by determining whether to perform transform processing on chroma components, using a reference value as a quantization parameter when transform processing is not performed, and applying corrected quantization parameters for chroma components when transform processing is skipped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a quantization parameter smaller than 4 is used to increase gradations, then image quality after compression is improved, but the amount of code increases unnecessarily when transform processing is not performed
Solution Approach 1:
The patent dynamically adjusts the quantization parameter based on the transform processing status. When transform processing is skipped, the quantization parameter is corrected to prevent it from being smaller than 4, thereby avoiding unnecessary code increase while maintaining image quality. This parameter adaptation resolves the contradiction by making the quantization parameter conditional on the processing mode.
Solution Approach 2:
The patent introduces a dynamic correction mechanism that modifies the quantization parameter based on real-time determination of transform processing status. The correction unit activates only when transform processing is not performed, creating a dynamic system that adapts to different encoding scenarios. This dynamic approach allows the system to optimize both image quality and code amount according to the specific encoding context.
2Productivity
If transform processing is skipped for chroma component encoding, then encoding efficiency is improved, but image quality does not improve and code amount increases
Solution Approach 1:
The patent applies parameter correction specifically for chroma component encoding when transform processing is skipped. By adjusting the quantization parameter under these conditions, the patent prevents degradation of image quality while maintaining the encoding efficiency benefits of skipping transform processing. This selective parameter modification resolves the contradiction between encoding efficiency and image quality.
3Loss of information
If quantization parameter is set below 4 to increase gradations, then more detail information is preserved, but code amount increases without corresponding quality improvement in transform-skipping mode
Solution Approach 1:
The patent implements a correction mechanism that prevents the quantization parameter from being set below 4 when transform processing is skipped. This ensures that detail information is preserved through appropriate quantization while avoiding the unnecessary increase in code amount that would occur with overly aggressive parameter reduction. The correction maintains an optimal balance between information preservation and code efficiency.
Data Source
AI summary
The block to be encoded is encoded using a first quantization parameter corresponding to a coefficient of each color component in the block to be encoded when it is determined that orthogonal transform processing is to be performed on the coefficient of each color component in the block to be encoded, and the block to be encoded is encoded using a second quantization parameter obtained by correcting the first quantization parameter when it is determined that orthogonal transform processing is not to be performed on the coefficient of each color component in the block to be encoded. A predetermined determination based on the first quantization parameter and a predetermined value is performed, and the second quantization parameter is derived by correcting the first quantization parameter in accordance with a determination result of the predetermined determination.