Chroma Intra Prediction Candidate Lists from Luma Modes

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Solution Overview

Problem

Existing image compression technologies face challenges in effectively configuring candidate lists and signaling mode information for intra prediction of chroma component blocks, leading to suboptimal compression performance and prediction accuracy.

Innovation Solution

An image decoding method and device construct a candidate list for chroma blocks based on the intra prediction mode of corresponding luma blocks, determining whether to apply a cross-component linear model (CCLM) or direct mode (DM), and generate prediction samples using this list, incorporating intra prediction modes from adjacent luma and chroma blocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a candidate list is constructed for intra prediction of chroma blocks using luma block modes, then prediction accuracy is improved, but device complexity increases

Engineering Contradiction:

Improveprediction accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the luma block's own intra prediction mode to automatically generate the candidate list for chroma prediction, eliminating the need for separate manual configuration. The luma block serves itself by providing its mode information directly to the chroma prediction process, reducing overall system complexity while maintaining accuracy.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The luma block's intra prediction mode serves multiple functions: it is used for luma prediction itself and simultaneously serves as the basis for generating chroma prediction candidates. This multi-functional use of the same data structure improves prediction accuracy without requiring additional separate mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If mode information for chroma intra prediction is signaled using a constructed candidate list, then compression performance is improved, but loss of information increases

Engineering Contradiction:

Improvecompression performanceVSAvoidloss of information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The essential information needed for chroma prediction is extracted from the luma block's mode data and placed into a candidate list structure. This extraction allows the system to use only the necessary mode information for prediction while encoding efficiency is improved through the structured candidate list format.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The candidate list is constructed in advance during the encoding process, organizing all possible chroma prediction modes before actual prediction occurs. This preliminary organization allows for more efficient signaling and reduces information loss by pre-establishing the prediction framework.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260025512A1Image encoding/decoding method and apparatus, and recording medium having bitstream stored therein

Publication Date: 2026.01.22 LG ELECTRONICS INC

AI summary

A device and method for decoding/encoding an image according to the present disclosure may configure a candidate list of a current chroma block based on an intra prediction mode of a luma block corresponding to the current chroma block, derive an intra prediction mode of the current chroma block based on the candidate list, and generate a prediction sample of the current chroma block based on the derived intra prediction mode.