In-loop Reshaping with Local Illumination Compensation
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Solution Overview
Problem
Current video coding standards face challenges in integrating effective reshaping and local illumination compensation techniques, leading to suboptimal coding efficiency and image quality, especially in next-generation video coding standards like VVC.
Innovation Solution
The proposed solution combines reshaping functions with local illumination compensation in video coding by processing neighboring samples in both the reshaped and original domains, using forward and inverse mapping functions to generate LIC parameters and update predicted samples, thereby enhancing coding efficiency and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reshaping functions are integrated with local illumination compensation in video coding, then coding efficiency and image quality improve, but computational complexity and processing overhead increase
Solution Approach 1:
The patent combines reshaping functions with local illumination compensation (LIC) into a unified processing pipeline. The LIC parameters are computed using both original-domain samples and reshaped-domain samples, merging two previously separate operations into one integrated process that improves coding efficiency while managing computational complexity through shared processing structures.
Solution Approach 2:
The processing is divided into distinct domains: original domain sample access, reshaped domain sample access, LIC parameter computation, and predicted sample generation. Each segment handles specific computations in its optimal domain, allowing parallel processing paths that improve efficiency while maintaining manageable complexity through modular organization.
2Measurement precision
If dual-domain processing (original and reshaped domains) is implemented, then illumination change modeling accuracy improves, but processing time and computational load increase
Solution Approach 1:
The patent pre-computes and stores both original-domain neighboring samples and reshaped-domain neighboring samples before LIC parameter computation. This preliminary preparation allows the actual illumination compensation to proceed efficiently using pre-processed data, reducing real-time processing time while maintaining high modeling accuracy through dual-domain information.
3Manufacturing precision
If LIC parameters are generated using both original and reshaped neighboring samples, then image quality improves, but memory requirements and data processing overhead increase
Solution Approach 1:
The patent applies different processing qualities to different domains: original-domain samples are used for capturing absolute illumination characteristics, while reshaped-domain samples are used for capturing relative illumination variations. Each domain contributes its specific quality advantage, allowing high image quality through complementary use of both domains without requiring all samples to be stored at maximum precision.
Data Source
AI summary
Methods, processes, and systems are presented for combining signal reshaping (also referred to as luma mapping chroma residuals scaling) with local illumination compensation (LIC) in video coding. Examples and trade-offs when the LIC model parameters are computed in the original domain, the reshaped domain, or a mixed domain, are presented.