Intra Prediction Template Selection for CCCM Chroma Coding
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Solution Overview
Problem
Existing video coding technologies fix the sets of reconstructed neighboring samples used for intra prediction regardless of the current coding unit's location, potentially leading to suboptimal coding efficiency.
Innovation Solution
A video coder determines a template based on a threshold and reference sample quantity, allowing selection from multiple templates, and applies a convolutional cross-component model (CCCM) for improved chroma sample prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed template of reconstructed neighboring samples is used for intra prediction, then the device complexity is reduced and ease of operation is improved, but the coding efficiency deteriorates due to suboptimal prediction quality
Solution Approach 1:
The patent implements dynamic template selection where the template configuration changes based on the current coding unit's location and characteristics. Multiple templates are defined with different configurations, and the appropriate template is selected dynamically rather than using a fixed template for all cases, thereby improving coding efficiency while maintaining reasonable operational complexity through systematic selection rules.
2Productivity
If multiple templates with different configurations are used for intra prediction, then the coding efficiency is improved through better prediction quality, but the device complexity increases due to additional template selection logic
Solution Approach 1:
The patent changes the parameter of template configuration based on the current coding unit's position and characteristics. Different templates are defined with varying numbers and arrangements of reference samples, and the selection of which template to use is determined by changing parameters such as the coding unit's location relative to picture boundaries and its size, thereby improving coding efficiency without requiring complex decision logic.
3Ease of operation
If template selection is performed without considering reference sample quantity thresholds, then the ease of operation is maintained, but the reliability of prediction quality deteriorates
Solution Approach 1:
The patent introduces a threshold parameter for the quantity of reference samples that determines whether template selection is performed. When the reference sample quantity meets the threshold condition, appropriate template selection is enabled to improve prediction quality; when the threshold is not met, a default template is used. This parameter-based approach maintains ease of operation while improving the reliability of prediction quality through conditional template selection.
Data Source
AI summary
A method of coding video data comprises determining, based on a comparison of a threshold and a quantity of reference samples in a selected template, whether the selected template is allowed, wherein a mode index indicates which template from among a plurality of templates is the selected template, wherein each of the templates includes a different set of reconstructed samples that neighbor a current coding unit (CU) of a current picture of the video data; based on determining that the selected template is allowed and that a convolutional cross-component model (CCCM) mode is to be used, applying the CCCM mode to predict chroma samples of the current CU based on reconstructed luma samples of the current CU and the reference samples in the selected template; and; and encoding or decoding the current CU based on the predicted chroma samples of the current CU.