Non-Square Intra Prediction With Wide-Angle Mode Mapping
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Solution Overview
Problem
Conventional intra prediction methods do not effectively utilize wide angular directions for non-square blocks and use a uniform intra smoothing filter, which is not optimal for all block sizes, leading to inefficient compression.
Innovation Solution
The method determines whether an angular intra prediction mode for a non-square block is a wide angle mode and applies an intra smoothing filter to neighboring blocks if a condition is satisfied, enhancing intra prediction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional intra prediction methods are used, then the prediction process is simple, but the compression efficiency is poor for non-square blocks
Solution Approach 1:
The patent segments the angular prediction modes into different categories (first angular modes and second angular modes) based on their directional characteristics relative to the block geometry. This segmentation allows the system to apply different prediction strategies to different mode types, improving compression efficiency for non-square blocks while maintaining manageable complexity through systematic classification.
Solution Approach 2:
The patent applies different intra smoothing filter characteristics to different angular prediction modes based on their local directional properties. By tailoring the filter parameters to match the specific angular direction and block geometry, the system optimizes prediction accuracy for each local region, thereby improving overall compression efficiency without requiring a completely complex global solution.
2Measurement precision
If a uniform intra smoothing filter is used, then the implementation is simple, but the prediction accuracy is suboptimal for different block sizes
Solution Approach 1:
The patent introduces dynamic filter configuration where the intra smoothing filter parameters are adjusted based on the block size and angular prediction mode. Instead of using a fixed uniform filter, the system dynamically selects filter characteristics that match the current processing context, improving prediction accuracy for different block sizes while controlling complexity through rule-based parameter selection.
Solution Approach 2:
The patent changes the filter parameters adaptively based on the block dimensions and prediction mode. By modifying filter characteristics (such as filter strength, kernel size, or boundary handling) according to the specific block size and angular direction, the system optimizes prediction accuracy for each configuration without requiring an entirely complex filter design, thus balancing precision and implementation complexity.
3Loss of information
If wide angular directions are not utilized, then the prediction method is simpler, but the bit rate increases for less likely directions
Solution Approach 1:
The patent segments angular prediction modes into first angular modes (within a first angular range) and second angular modes (within a second angular range), allowing the system to handle different directional cases separately. This segmentation enables optimized prediction for wide angular directions while maintaining simpler handling for conventional directions, improving bit rate efficiency without proportionally increasing overall complexity.
Solution Approach 2:
The patent applies enhanced prediction processing (including intra smoothing filtering) selectively to specific angular modes that benefit most from it, rather than uniformly applying complex processing to all modes. By focusing computational resources on the most critical cases (wide angular directions for non-square blocks), the system achieves better bit rate efficiency for those cases while keeping the overall system complexity manageable through partial application of advanced techniques.
Data Source
AI summary
In a method for video decoding, a determination is made as to whether an angular intra prediction mode for a current block which is a non-square block is a wide angle mode outside a range of directions spanning a bottom left diagonal direction and a top right diagonal direction of the current block. When the angular intra prediction mode is the wide angle mode, whether a condition for applying an intra smoothing filter to blocks neighboring the current block is met is determined. When the condition is met, the intra smoothing filter is applied to the neighboring blocks and intra prediction is performed with a coding tool based on the filtered blocks to obtain a feature value for the current block. When the coding tool is a Non-Separable Secondary Transform, the wide angle mode is mapped to a conventional intra prediction mode within the range of directions.