Image Coding Unit Prediction with Multiple Reference Lines
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Solution Overview
Problem
Existing image coding systems limit coding quality and efficiency due to the use of a single reference line for prediction mode determination, which does not effectively reduce data redundancy.
Innovation Solution
The system divides a coding unit into multiple coding sub-units, determines multiple reference lines for each sub-unit, and uses most probable mode (MPM) lists to enhance prediction accuracy, employing various filters and prediction modes based on sub-unit characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one reference line closest to a left side and an upper side of the coding sub-unit is used to determine the prediction mode, then the device complexity is reduced, but the coding quality and compression performance deteriorate due to limited ability to reduce data redundancy
Solution Approach 1:
The patent segments the reference line construction into multiple distinct reference lines (first reference line from left side, second reference line from upper side) instead of using a single reference line. This segmentation allows different regions of the coding sub-unit to utilize the most appropriate reference line, improving prediction accuracy and coding quality while maintaining manageable complexity through structured organization of multiple reference lines.
2Speed
If only one reference line is used for prediction mode determination, then the processing speed is improved, but the data redundancy reduction and compression performance worsen
Solution Approach 1:
The patent introduces a second dimension for reference line selection by constructing both a first reference line (from left side) and a second reference line (from upper side), transforming the single-reference-line approach into a multi-dimensional reference system. This allows the prediction mode determination to consider multiple directional references simultaneously, reducing data redundancy by capturing more comprehensive spatial information while maintaining efficient processing through organized candidate lists.
3Reliability
If multiple reference lines and MPM lists are used for each coding sub-unit, then the coding quality and compression performance improve by reducing data redundancy, but the device complexity and processing overhead increase
Solution Approach 1:
The patent applies local quality by constructing different MPM lists (first MPM list corresponding to first reference line, second MPM list corresponding to second reference line) tailored to specific regions and prediction directions within the coding sub-unit. Each local region utilizes the most appropriate reference line and corresponding MPM list, optimizing prediction accuracy for that specific area while managing overall complexity through localized rather than uniform processing.
Solution Approach 2:
The patent changes parameters by dynamically selecting different reference lines and corresponding MPM lists based on the prediction mode and coding sub-unit characteristics. The system adjusts which reference line (first or second) and which MPM list to use depending on the specific coding context, transforming fixed-parameter approaches into adaptive parameter selection that improves coding quality while controlling complexity through conditional logic.
Data Source
AI summary
An image coding system is provided. The system may determine a coding unit in an image and divide the coding unit into a plurality of coding sub-units. For at least one coding sub-unit of the plurality of coding sub-units, the system may determine multiple reference lines of the at least one coding sub-unit. The system may determine a target prediction mode associated with one of the at least one coding sub-unit. The system may determine a predicted coding sub-unit corresponding to the one of the at least one coding sub-unit based on the target prediction mode and the multiple reference lines of the at least one coding sub-unit. The system may determine a predicted coding unit corresponding to the coding unit based at least in part on the predicted coding sub-unit.