Intra Prediction Mode Derivation With Split MPM Candidate Groups
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Solution Overview
Problem
Existing image compression technologies face challenges in accurately and efficiently determining intra prediction modes, particularly for high-resolution and high-quality images, which affects the efficiency of image encoding and decoding processes.
Innovation Solution
An image encoding/decoding method and apparatus that determines a reference region for intra prediction, divides the MPM candidate group into first and second groups, and derives the intra prediction mode based on these groups, using predefined pixel lines and flags to select the appropriate mode for current blocks, including luma and chroma blocks, and performs adaptive block division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intra prediction mode is derived using traditional methods, then the encoding process is simpler, but the prediction accuracy and compression efficiency are insufficient for high-resolution images
Solution Approach 1:
The MPM candidate group is divided into two distinct groups: a first group containing default modes (planar mode and DC mode) and a second group containing neighboring block modes. This segmentation allows the encoder to selectively apply different derivation methods based on the specific block characteristics, improving prediction accuracy while managing complexity through structured organization of candidate modes.
Solution Approach 2:
The patent implements dynamic selection between the first group and second group of MPM candidates based on block type (luma or chroma) and spatial position. The encoder adaptively chooses which group to use for deriving intra prediction modes, allowing the system to optimize prediction accuracy for different image regions and block characteristics rather than using a static approach.
2Manufacturing precision
If more MPM candidate groups are used to improve prediction accuracy, then the encoding precision increases, but the computational complexity and processing time increase
Solution Approach 1:
Instead of evaluating all possible intra prediction modes, the patent uses a partial approach by maintaining two focused MPM candidate groups that cover the most likely prediction modes. The first group provides default fallback options while the second group provides context-adaptive options from neighboring blocks, achieving high precision without the computational burden of exhaustive mode evaluation.
Solution Approach 2:
The patent applies different MPM candidate groups based on local block characteristics - using the first group for certain block types or positions and the second group for others. This local quality approach ensures that each block receives the most appropriate candidate group for its specific characteristics, optimizing precision locally while maintaining overall encoding efficiency.
3Productivity
If adaptive block division is implemented for intra prediction, then the prediction efficiency for different regions improves, but the device complexity and processing overhead increase
Solution Approach 1:
The patent divides the current block into multiple sub-blocks and performs intra prediction separately for each sub-block using the MPM candidate groups. This segmentation allows different prediction modes to be applied to different regions of the block, improving overall prediction efficiency by capturing local variations in image content while maintaining manageable processing complexity through systematic subdivision.
Data Source
AI summary
A method and a device for encoding/decoding an image according to the present invention may determine a reference region for intra prediction of a current block, derive an intra prediction mode of the current block on the basis of a predetermined MPM candidate group, and perform intra prediction on the current block on the basis of the reference region and the intra prediction mode.