Chroma Interpolation Filter Using 1/8-Pel Accuracy
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Solution Overview
Problem
Current video codec standards face increased calculation difficulty due to the 1/8-pel accuracy of chroma interpolation, which is inadequate in performance compared to luma interpolation's 1/4-pel accuracy.
Innovation Solution
A chroma interpolation method using a 4-tap interpolation filter for two-dimensional separated interpolation, with specific coefficients for different fractional-pel positions, performing one-dimensional filtering in both horizontal and vertical directions to achieve 1/8-pel accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chroma interpolation uses 1/8-pel accuracy with multiple fractional-pel pixels, then the precision is improved, but the calculation difficulty increases
Solution Approach 1:
The patent divides the two-dimensional interpolation process into separate one-dimensional filtering operations in horizontal and vertical directions. This segmentation allows the complex 2D interpolation to be broken down into simpler 1D operations, reducing calculation complexity while maintaining 1/8-pel precision for chroma interpolation
Solution Approach 2:
The patent transforms the two-dimensional interpolation problem into a sequence of one-dimensional filtering operations. By applying 1D filters separately in horizontal and vertical directions, the method simplifies the computational burden of direct 2D interpolation while achieving the same precision goal
2Ease of operation
If bilinear interpolation is used, then the calculation process is simple, but the performance is inadequate
Solution Approach 1:
The patent modifies the interpolation parameters by using specific filter coefficients designed for 1/8-pel accuracy rather than standard bilinear coefficients. This parameter change improves interpolation performance while the filter-based approach maintains computational efficiency through the segmented 1D filtering structure
Data Source
AI summary
A chroma interpolation method, including: 1) determining a pixel accuracy for interpolation; 2) determining coordinate positions of interpolated fractional-pel pixels between integer-pel pixels; and 3) performing two-dimensional separated interpolation on the interpolated fractional-pel pixels by an interpolation filter according to the coordinate positions. The invention also provides a filter device using the above method for chroma interpolation.