Bi-Predicted Illumination Compensation for Motion Prediction
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Solution Overview
Problem
Existing video coding systems struggle to effectively address local illumination changes among temporal neighboring pictures, which can degrade video quality.
Innovation Solution
Implement local illumination compensation (LIC) parameters based on bi-predicted reference template samples to adjust samples for current coding units, using a least mean square error approach to minimize differences and apply these parameters at the overlapped block motion compensation stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If local illumination compensation parameters are calculated based on bi-predicted reference template samples, then video quality is improved by compensating for local illumination changes, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent calculates LIC parameters at the motion compensation stage using bi-predicted reference template samples before the OBMC stage. This preliminary calculation allows the illumination compensation parameters to be prepared in advance, reducing the processing burden at later stages while maintaining video quality improvement.
Solution Approach 2:
The patent introduces bi-predicted reference template samples as an intermediary between the reference pictures and the current picture processing. These template samples serve as a mediator to capture local illumination characteristics, which then guide the compensation process without requiring direct complex comparisons between reference and current pictures.
2Productivity
If LIC parameters are calculated at the motion compensation stage, then processing efficiency is improved by enabling early parameter availability, but measurement precision may be affected due to earlier processing timing
Solution Approach 1:
The patent uses a least mean square error approach to calculate LIC parameters, which provides a feedback mechanism that minimizes the difference between bi-predicted reference template samples and template samples. This optimization ensures that even though processing occurs early at the motion compensation stage, the parameters achieve high precision through iterative error minimization.
3Adaptability or versatility
If bi-predicted reference template samples are used for LIC parameter calculation, then adaptability to local illumination changes is improved, but device complexity increases due to additional sample processing
Solution Approach 1:
The patent applies local illumination compensation by calculating LIC parameters specifically for regions where illumination changes are detected. Instead of uniformly processing all blocks, the system adapts the compensation approach to local characteristics, using bi-predicted reference template samples only where needed to capture local illumination variations.
Data Source
AI summary
Systems, methods, and instrumentalities are described herein for calculating local illumination compensation (LIC) parameters for bi-predicted coding unit (CU). The LIC parameters may be used to generate adjusted samples for the current CU and to address local illumination changes that may exist among temporal neighboring pictures. LIC parameters may be calculated based on bi-predicted reference template samples and template samples for a current CU. Bi-predicted reference template samples may be generated based on reference template samples neighboring temporal reference CUs. For example, the bi-predicted reference template samples may be generated based on averaging the reference template samples. The reference template samples may correspond to template samples for the current CU. A CU may be or may include a coding block and/or a sub-block that may be derived by dividing the coding block.