Local Illumination Compensation for Video Encoding
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Solution Overview
Problem
Existing video encoding and decoding methods struggle with efficiently addressing illumination variations across frames, leading to suboptimal compression efficiency and increased complexity.
Innovation Solution
The implementation of a local illumination compensation (LIC) method that applies a linear function to predicted samples, where the function parameters are determined based on selected reference samples, to compensate for illumination changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing video encoding and decoding methods are used, then the processing complexity and memory bandwidth requirements are reduced, but the compression efficiency deteriorates due to inability to handle illumination variations
Solution Approach 1:
The patent divides the video processing into distinct stages: prediction stage, illumination compensation stage, and residual coding stage. The illumination compensation is applied locally to specific blocks using separate linear functions for different regions, allowing independent optimization of each segment without increasing overall system complexity
Solution Approach 2:
The illumination compensation is performed preliminarily on the predicted samples before the residual calculation and encoding stages. By pre-compensating for illumination variations in the prediction step, the method reduces the complexity of subsequent processing stages and improves compression efficiency without adding significant overall complexity
2Productivity
If illumination compensation is applied to handle illumination variations, then the compression efficiency is improved, but the processing complexity and memory bandwidth requirements increase
Solution Approach 1:
The patent applies local illumination compensation where different linear functions are used for different spatial blocks. Each block's illumination characteristics are compensated independently using locally adapted parameters, which improves compression efficiency for regions with varying illumination while keeping the processing complexity localized and manageable
Solution Approach 2:
The method changes the parameters of the prediction model by introducing illumination compensation parameters (linear function coefficients) that are derived from reference samples. These parameter changes allow the system to adapt to illumination variations without fundamentally changing the overall processing pipeline architecture
3Productivity
If illumination compensation is applied to handle illumination variations, then the compression efficiency is improved, but the memory bandwidth requirements increase
Solution Approach 1:
The patent extracts only the necessary reference samples from the reference picture that are needed for illumination compensation parameter calculation. By selecting and using only the relevant samples rather than processing entire blocks or frames, the method reduces memory bandwidth requirements while maintaining compression efficiency
Solution Approach 2:
The method applies partial illumination compensation by using a subset of available reference samples and applying compensation only where illumination variations are detected. This partial action approach improves compression efficiency for affected regions without requiring full processing of all picture data, thus reducing overall memory bandwidth requirements
Data Source
AI summary
A method for reconstructing a picture block is disclosed, wherein the block is predicted using local illumination compensation. The parameters of local illumination compensation parameters are determined according a selection of reconstructed samples located to the left and above the current block. In the case where some of them are unavailable, they may be replaced by others, using different techniques.