Intra Prediction MPM Mapping for Efficient Video Decoding
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Solution Overview
Problem
The existing intra prediction modes in video coding standards like HEVC and VVC are complex and inefficient, particularly due to the constant index list of non-selected modes, which hinders optimal compression and decoding efficiency.
Innovation Solution
Implementing a Most Probable Modes (MPM) scheme for intra-prediction that adapts the non-selected mode set based on current block properties and neighboring block modes, using a mapping process to simplify calculations and improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant index list is used for non-selected modes in intra prediction, then the decoding process is simplified, but the compression efficiency deteriorates
Solution Approach 1:
The patent transforms the static constant index list into a dynamic adaptive index list that varies based on neighboring block prediction modes. The index list is constructed by selecting from a set of candidate modes (including planar, DC, and directional modes) based on the actual prediction characteristics of adjacent blocks, allowing the decoding process to adapt to different image contents while maintaining efficiency
2Productivity
If more intra prediction modes are supported to improve compression performance, then the coding flexibility is improved, but the device complexity increases
Solution Approach 1:
The patent segments the 67 intra prediction modes into two distinct sets: a first set containing 6 most probable modes (MPM) that are signaled adaptively based on neighboring blocks, and a second set containing remaining modes that use a constant index list. This segmentation allows the system to maintain support for multiple modes while reducing complexity by using different signaling strategies for different mode groups
Solution Approach 2:
The patent applies different coding strategies to different prediction modes based on their probability and importance. The 6 most probable modes receive adaptive signaling with variable index lists tailored to local block characteristics, while less probable modes use a simplified constant index list, optimizing the balance between compression performance and decoding complexity
Data Source
AI summary
A decoding method and a decoder for decoding a current block of a video frame is provided, wherein the decoding method comprises determining a list of Most Probable Modes (MPMs) for the current block. When at least one condition is satisfied, the list of MPMs includes a DC mode, a Vertical mode, a Horizontal mode, an intra prediction mode corresponding to a value of the Vertical mode with a first offset, and an intra prediction mode corresponding to the value of the Vertical mode with a second offset. The decoding method further includes obtaining a MPM flag and a MPM index for the current block from a bitstream of the video, and obtaining an intra prediction mode for the current block for reconstructing the current block.