Video Intra Prediction Reference Lines for Accuracy-Complexity Balance

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Solution Overview

Problem

Existing video encoding/decoding technologies face inefficiencies in performing intra prediction, particularly in handling high-resolution and high-quality images, which leads to increased data transmission and storage costs.

Innovation Solution

A method and apparatus for determining an intra prediction mode and reference sample lines for a current block in video encoding/decoding, utilizing multiple reference samples, including those adjacent to the left/right and upper/lower parts of the block, and calculating prediction values through weighted sums or averages based on distances and weights applied to these samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional intra prediction using limited reference samples is used, then device complexity is reduced, but manufacturing precision (prediction accuracy) deteriorates

Engineering Contradiction:

Improveprediction accuracyVSAvoidcomplexity of reference sample processing

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The current block is divided into multiple sub-blocks, and different reference sample lines are selected for each sub-block based on its position and characteristics. This segmentation allows the system to use multiple reference samples without uniformly increasing complexity across the entire block, thereby improving prediction accuracy while managing device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different reference sample lines (first, second, third reference sample lines) are selectively applied to different regions or sub-blocks within the current block based on local characteristics. This local quality approach ensures that each region uses the most appropriate reference samples, improving overall prediction accuracy without requiring complex global processing.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If multiple reference sample lines are used for intra prediction, then prediction accuracy is improved, but loss of time (processing time) increases

Engineering Contradiction:

Improveprediction accuracyVSAvoidintra prediction processing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The selection of reference sample lines is dynamically adapted based on the characteristics of each sub-block and its position within the current block. This dynamic approach allows the system to use multiple reference samples when beneficial while avoiding unnecessary processing in regions where fewer samples suffice, thereby improving prediction accuracy while minimizing processing time.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes parameters such as the number and type of reference sample lines used based on local block characteristics, prediction mode, and position within the picture. This parameter adaptation allows the system to optimize between prediction accuracy and processing time by using more reference samples only when and where needed.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12375676B2Method and apparatus for video signal processing determining reference sample lines for a prediction target sample

Publication Date: 2025.07.29 KT CORP

AI summary

According to the present invention, there is provided a method of decoding an image, the method including: determining an intra prediction mode of a current block; determining a reference sample line for a prediction target sample included in the current block; and obtaining a prediction value of the prediction target sample on the basis of the intra prediction mode and the reference sample line.