Block Adaptive Weighted Prediction for Local Illumination Compensation
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Solution Overview
Problem
Existing video coding and decoding technologies struggle to effectively address local illumination variations, leading to inefficiencies in compression and transmission of video data.
Innovation Solution
Implementing Block Adaptive Weighted Prediction (BAWP) and Local Illumination Compensation (LIC) to enhance video encoding and decoding processes by using a scale factor and offset to predict current blocks based on reference blocks, allowing for improved modeling of local illumination changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If block adaptive weighted prediction (BAWP) and local illumination compensation (LIC) methods are used to compensate local illumination variation, then prediction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies parameter changes by using a linear equation with scale factor (α) and offset (β) to model illumination variations. The syntax element indicates the scale factor, which is determined based on its value, and the equation p′(x′)=α*p(x)+β is used to predict current blocks. This parameter-based approach improves prediction accuracy while controlling signaling overhead through adaptive precision signaling.
Solution Approach 2:
The patent implements dynamics through adaptive precision signaling for the scale factor. The precision of the scale factor is adjusted dynamically based on its value, allowing the system to maintain high prediction accuracy when needed while reducing signaling overhead when the scale factor is stable or has limited impact on prediction quality.
2Measurement precision
If adaptive precision signaling is used for scale factor, then prediction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent changes the precision parameter of the scale factor adaptively. The decoder receives a syntax element indicating the scale factor and determines the actual scale factor value based on this syntax element and the adaptive precision rules. This approach improves prediction accuracy through higher precision where needed while managing device complexity through standardized adaptive precision mechanisms.
3Reliability
If linear equation with scale factor and offset is used for prediction, then illumination compensation effectiveness is improved, but computational complexity increases
Solution Approach 1:
The patent uses a linear equation p′(x′)=α*p(x)+β with scale factor (α) and offset (β) parameters to model illumination variations. This simple parametric model improves illumination compensation effectiveness while maintaining relatively low computational complexity compared to more complex illumination modeling approaches.
Solution Approach 2:
The patent applies local quality by using block adaptive weighted prediction, where different blocks can have different scale factors and offsets. This allows the illumination compensation to be tailored to local characteristics of different blocks, improving effectiveness while keeping the computational approach localized and efficient.
Data Source
AI summary
This disclosure relates generally to video coding/decoding and particularly for enhancing block adaptive weighted prediction. One method includes receiving a video bitstream comprising a current block and a reference block, the reference block being used for predicting the current block and being identified by a motion vector associated with the current block; receiving, from the video bitstream, a syntax element indicating a scale factor (α); determining the scale factor (α) based on a value of the syntax element; predicting the current block using an equation p′(x′)=α*p(x)+β, where: p′(x′) is a predicted sample in the current block, p(x) is a collocated reference sample in the reference block corresponding to p′(x′), α is the determined scale factor based on the value of the syntax element, and β is an offset; and reconstructing the current block based on the predicted current block.