Intra Prediction Flag Signaling for Lower-Bitrate Image Decoding

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Solution Overview

Problem

The increasing demand for high-resolution and high-quality images leads to a surge in transmission and storage costs due to the increased amount of information, necessitating a high-efficiency image compression technology.

Innovation Solution

An image encoding/decoding method that efficiently changes the signaling structure for intra prediction modes based on importance information, reducing the amount of information required for commonly used modes and increasing the amount for less frequently used modes to enhance compression efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high-resolution and high-quality images are transmitted, then image quality is improved, but transmission cost increases

Engineering Contradiction:
Improveimage qualityVSAvoidtransmission cost
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent extracts and transmits only the essential intra prediction mode information using application flags, separating critical data from redundant data. This allows high-quality image transmission by preserving important prediction information while eliminating unnecessary data, thereby reducing transmission cost.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter representation by using application flags to indicate whether specific intra prediction modes are applied, rather than transmitting complete mode information for all blocks. This parameter change reduces the amount of data transmitted while maintaining image quality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complete intra prediction mode information is transmitted for all blocks, then decoding accuracy is improved, but bit rate increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidbit rate
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the necessary intra prediction mode application flags from the complete mode information, transmitting only what is essential for accurate decoding. This extraction approach maintains decoding accuracy by preserving critical mode selection information while significantly reducing the bit rate.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by transmitting intra prediction mode information selectively through application flags rather than complete information for all blocks. This partial transmission is sufficient to maintain decoding accuracy while reducing bit rate.

Inventive Principle:
Principle #16Partial or excessive action

3Quantity of substance

If intra prediction mode information is reduced, then bit rate is reduced, but encoding complexity increases

Engineering Contradiction:
Improvebit rateVSAvoidencoding complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-determining which intra prediction modes are applied and representing them with application flags before transmission. This preliminary organization of information simplifies the encoding process despite the reduced information format, as the flag-based representation is more straightforward to generate and transmit.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4648407A1Image encoding/decoding method based on intra prediction, method for transmitting bitstream, and recording medium storing bitstream
Publication Date: 2025.11.12 LG ELECTRONICS INC
  • EP4648407A1 patent drawingFigure 1
  • EP4648407A1 patent drawingFigure 2
  • EP4648407A1 patent drawingFigure 3

AI summary

An image encoding/decoding method and device are provided. An image decoding method according to the present disclosure may comprise the steps of: on the basis of intra prediction information of a luma component block of a current block, generating an intra prediction block of the luma component block; and restoring the current block on the basis of the intra prediction block, wherein the intra prediction information includes an intra prediction mode application flag indicating whether to apply a corresponding mode for each intra prediction mode, the intra prediction mode application flag includes a most probable mode (MPM) mode application flag and a template-based intra mode derivation (TIMD) mode application flag, and the MPM mode application flag is signaled before the TIMD mode application flag.