Intra Prediction Mode Signaling With MFM and MPM Indicators

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Solution Overview

Problem

Existing image encoding/decoding technologies face inefficiencies in intra prediction mode signaling due to diverse block partitioning and limited reference samples for inter color component prediction, leading to increased bit overhead and performance degradation.

Innovation Solution

The method introduces a Most Frequent Mode (MFM) indicator to determine the intra prediction mode of a current block, and constructs a Most Probable Mode (MPM) list excluding the predetermined mode, using specific neighboring blocks for improved encoding/decoding efficiency and inter color component prediction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of intra prediction modes increases to improve prediction accuracy, then the prediction quality is improved, but the bit overhead for signaling the prediction modes increases

Engineering Contradiction:

Improveprediction accuracyVSAvoidbit overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the intra prediction modes into two groups: MPM (Most Probable Mode) candidates and non-MPM candidates. The MPM list contains the most frequently occurring modes derived from neighboring blocks, while non-MPM modes are handled separately. This segmentation allows the encoder to signal only the necessary information - a flag indicating whether the mode is in the MPM list and an index if it is - thereby reducing bit overhead while maintaining access to all prediction modes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation by using a two-stage signaling approach: first signaling whether the intra prediction mode is included in the MPM list (using 1 bit), and then signaling the specific mode index only when necessary. This parameter change optimizes the bit allocation based on the probability distribution of mode occurrences, reducing overall bit overhead while preserving all 35 intra prediction modes

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If block partitioning is diversified to improve coding flexibility, then the adaptability to different image regions is improved, but the prediction mode of neighboring blocks becomes more diversified and less predictable

Engineering Contradiction:

Improvecoding flexibilityVSAvoidprediction reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent creates a universal MPM list construction method that works across all block partitioning types (symmetric, asymmetric, vertical, horizontal). The MPM candidates are derived from available neighboring blocks using a standardized approach that adapts to different partitioning configurations. This universal method ensures reliable prediction mode selection regardless of the specific partitioning pattern used in the image

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent dynamically adjusts the MPM list construction based on the actual availability of neighboring blocks. Depending on the block partitioning configuration, different neighboring blocks may be available or unavailable, and the MPM list is constructed adaptively using only the available neighbors. This dynamic approach maintains prediction reliability while supporting diverse block partitioning schemes

Inventive Principle:

Principle #15Dynamics

3Device complexity

If a fixed and limited reference sample is used for inter color component prediction to simplify the process, then the complexity is reduced, but the performance of inter color component prediction degrades

Engineering Contradiction:

Improveprediction process complexityVSAvoidprediction performance

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary classification of the current block into two categories: blocks where the luma and chroma blocks have the same position, and blocks where they have different positions. Based on this preliminary classification, different reference sample selection strategies are applied. This preliminary action enables the use of more reference samples and adaptive prediction for blocks that benefit from it, while maintaining simplicity for blocks where the fixed approach suffices

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies different prediction strategies to different local regions (blocks) based on their specific characteristics. For blocks where luma and chroma positions differ, the patent uses adaptive reference sample selection and linear prediction models tailored to that specific block's geometry. For blocks with aligned positions, the simpler fixed reference sample approach is used. This local quality approach optimizes prediction performance for each block type while managing overall complexity

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260046397A1Image encoding/decoding method and device using MFM indicator and MPM indicator, and recording medium in which bitstream is stored

Publication Date: 2026.02.12 ELECTRONICS & TELECOMM RES INST

AI summary

There is provided an image encoding/decoding method and apparatus. An image decoding method according to the present invention may comprise reconstructing a most frequent mode (MFM) indicator indicating whether or not an intra prediction mode of a current block is a predetermined intra prediction mode, deriving, on the basis of the MFM indicator, the intra prediction mode of the current block, and generating a prediction block of the current block by performing intra prediction on the current block on the basis of the intra prediction mode.