Triangular Prediction Mode for Lower-Complexity Image Decoding
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Solution Overview
Problem
Existing image encoding and decoding methods face challenges in efficiently managing prediction modes, leading to unnecessary information in bitstreams and complexity in the encoding and decoding processes.
Innovation Solution
The proposed solution involves an image decoding method that sets restrictions on the prediction mode of a current block by using a triangle prediction mode, splitting the block into two triangular partitions, generating a merge list, selecting a motion vector, and reconstructing the block based on prediction blocks obtained from a reference image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current block is predicted by using multiple prediction modes without restrictions, then prediction accuracy may be improved, but unnecessary information is included in the bitstream and the encoding/decoding process becomes more complex
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the prediction mode based on block characteristics. Specifically, it changes the prediction mode parameter from a general block-based mode to a triangular partition-based mode when certain conditions are met (e.g., when the block width-to-height ratio exceeds a threshold). This allows the system to use simpler prediction modes for regular blocks while employing more complex triangular prediction only when beneficial, thereby resolving the contradiction between prediction accuracy and process complexity.
Solution Approach 2:
The patent segments the current block into two triangular partitions along a diagonal line when triangular prediction mode is selected. This segmentation allows for more precise local prediction within each triangle while maintaining overall block coherence. The segmentation is conditional and only applied when it improves efficiency, thus avoiding unnecessary complexity for blocks that don't benefit from triangular division.
2Productivity
If triangular prediction mode is applied to all current blocks, then prediction efficiency is improved, but the bitstream contains unnecessary information and processing overhead increases
Solution Approach 1:
The patent implements a dynamic prediction mode selection mechanism that adapts to each current block's characteristics. The system dynamically determines whether to apply triangular prediction mode based on real-time analysis of block properties (such as width-to-height ratio and gradient characteristics). This dynamic approach ensures triangular prediction is applied only when it provides actual efficiency gains, preventing unnecessary information from being encoded in the bitstream and avoiding processing overhead for blocks where triangular prediction would not be beneficial.
3Measurement precision
If motion vector precision is increased using sub-pel interpolation, then prediction accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent applies partial action by selectively performing sub-pel interpolation only when triangular prediction mode is selected and only for the specific triangular partitions that benefit from it. For blocks where regular prediction mode is used or where triangular prediction is not beneficial, the system performs only integer-pel motion estimation. This partial application of high-precision interpolation reduces overall computational complexity and processing time while maintaining high motion vector precision where it is most needed.
Data Source
AI summary
An image decoding method including: obtaining, from a bitstream, information related to a triangle prediction mode for a current block; splitting the current block into two triangular partitions, according to the information related to a triangle prediction mode; generating a merge list for a triangle prediction mode, according to a merge list generation method in a regular merge mode; selecting a motion vector for the two triangular partitions according to information indicating the motion vector from among motion vectors included in the merge list; obtaining, from a reference image, prediction blocks corresponding to the two triangular partitions, based on the motion vector; and reconstructing the current block, based on a final prediction block.