Block Level Adaptive Weighted Prediction Illumination Compensation
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Solution Overview
Problem
Current video coding technologies face challenges in effectively addressing local illumination variations through block level adaptive weighted prediction (BAWP), which affects the efficiency of video compression and decoding processes.
Innovation Solution
The implementation of a method that involves selecting a scaling factor look-up table based on the inter prediction mode and picture order count (POC) distance to determine a scaling factor for reconstructing video blocks, using a linear equation to compensate for local illumination changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block level adaptive weighted prediction is used to compensate local illumination variation, then video compression efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments the illumination compensation process by dividing the video image into multiple blocks and applying different scaling factors to each block based on its characteristics. This allows the system to handle local illumination variations effectively while managing complexity through structured block processing.
Solution Approach 2:
The patent changes the scaling factor parameter adaptively for different blocks based on their illumination characteristics. By adjusting this parameter dynamically rather than using a fixed value, the system improves compression efficiency while keeping the overall complexity manageable through parameterization.
2Measurement precision
If multiple scaling factor look-up tables are used to improve prediction accuracy, then local illumination compensation is enhanced, but data processing time increases
Solution Approach 1:
The patent pre-computes and stores multiple scaling factor look-up tables during the encoding phase, so that during decoding the system can directly retrieve appropriate scaling factors without performing complex calculations in real-time. This preliminary action reduces processing time while maintaining high prediction accuracy.
Solution Approach 2:
The patent uses look-up tables that store pre-computed scaling factors as copies of optimal values for different block types. This allows the decoder to retrieve accurate scaling factors quickly without recalculating them, thus reducing processing time while maintaining prediction precision.
3Adaptability or versatility
If scaling factor look-up tables of large size are used to cover more illumination conditions, then illumination compensation coverage is improved, but memory requirements increase
Solution Approach 1:
The patent segments the illumination compensation into multiple smaller look-up tables, each dedicated to specific block types or illumination conditions. This segmentation allows the system to cover various illumination scenarios while keeping each individual table small, thus reducing overall memory requirements compared to a single large table.
Solution Approach 2:
The patent applies different scaling factor tables tailored to specific local block characteristics rather than using a single universal table. This local quality approach allows efficient illumination compensation for different regions while minimizing the total memory needed by only storing scaling factors relevant to each specific block type.
Data Source
AI summary
This disclosure relates generally to video coding/decoding and particularly for improving block level adaptive weighted prediction. One method includes receiving the coded video bitstream comprising the current block of the current frame and a syntax element indicating a prediction mode for the current block, a plurality of scaling factor look-up tables being stored; determining the prediction mode based on a value of the syntax element, the prediction mode being used for predicting the current block based on a reference block of a reference frame; selecting a scaling factor look-up table from the plurality of scaling factor look-up tables based on an inter prediction mode of the current block or a picture order count (POC) distance between the reference frame and the current frame; determining a scaling factor from the selected scaling factor look-up table; and reconstructing the current block based on the reference block and the determined scaling factor.