Intra Prediction Filter Selection for Non-Square Video Blocks
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Solution Overview
Problem
Existing methods for determining whether to filter reference pixels in intra prediction fail to accurately account for the size characteristics of prediction blocks that are not square, leading to suboptimal filtering effects due to the use of log 2Size, which cannot distinguish between different aspect ratios.
Innovation Solution
A system and method for intra prediction that selects a candidate prediction block based on its aspect ratio, side lengths, and logarithmic functions of these parameters to determine a suitable filter for filtering reference pixels, allowing for more precise filtering based on the block's dimensions and angular prediction mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If log 2Size is used to determine whether to filter reference pixels, then the determination process is simple, but the filtering effect deteriorates for non-square prediction blocks
Solution Approach 1:
The patent changes the parameter used for determination from log 2Size to aspect ratio (width/height). This parameter change allows the system to distinguish between different block shapes (square vs. non-square) while maintaining a simple determination process. The aspect ratio directly reflects the geometric characteristics of prediction blocks, enabling accurate filtering decisions for both square and non-square blocks.
2Adaptability or versatility
If log 2Size is used for filter determination, then the method is unified for all block sizes, but it cannot adapt to different aspect ratios
Solution Approach 1:
The patent introduces aspect ratio as a new parameter for filter determination, which naturally adapts to different block shapes. By using width/height ratio, the system automatically distinguishes between square blocks (ratio=1) and non-square blocks (ratio≠1), enabling shape-adaptive filtering without requiring complex multi-condition logic.
3Manufacturing precision
If a single filter is used for all prediction blocks, then the implementation is simple, but the prediction accuracy deteriorates for non-square blocks
Solution Approach 1:
The patent uses aspect ratio as the basis for filter selection, which provides a clear and simple distinction between square and non-square blocks. This parameter-based approach enables accurate filter determination without complex calculations, as the aspect ratio directly indicates the block shape and can be used to select appropriate filters from predefined sets.
Data Source
AI summary
The present disclosure relates to systems and methods for intra prediction. The methods may include selecting a candidate prediction block from a plurality of prediction blocks of a video slice according to a first condition, wherein a width of the candidate prediction block is different from a height of the candidate prediction block; selecting an angular prediction mode from a plurality of candidate prediction modes of the candidate prediction block; and determining a filter for the angular prediction mode of the candidate prediction block according to a second condition.