Adaptive Interpolation Filter Set for Video Coding Efficiency
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Solution Overview
Problem
Existing video coding systems with Motion Estimation (ME)/Motion Compensation (MC) require inefficient interpolation methods for fractional pixel accuracy, leading to suboptimal coding performance and increased bandwidth, despite advancements like region-based adaptive interpolation filters.
Innovation Solution
An adaptive interpolation filter set is applied based on pixel location and characteristics, using longer taps for internal samples and shorter taps for boundary samples, and region-specific filtering to optimize interpolation without increasing bandwidth or computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed interpolation filter set is used, then computation complexity is reduced, but coding performance deteriorates
Solution Approach 1:
The patent applies dynamic selection of interpolation filter sets based on motion characteristics. The system switches between different filter sets (e.g., 8-tap, 6-tap, 4-tap) depending on the motion complexity and pixel location, making the filtering process adaptive rather than fixed. This resolves the contradiction by allowing high performance when needed while reducing complexity when motion is simple.
Solution Approach 2:
The patent applies different interpolation filter sets to different regions within the same block based on local motion characteristics and distance from block boundaries. Internal pixels may use longer-tap filters while boundary pixels use shorter-tap filters, optimizing coding performance locally without uniformly increasing complexity across the entire block.
2Manufacturing precision
If region-based adaptive interpolation filter is applied, then coding performance is improved, but bandwidth requirement increases
Solution Approach 1:
The patent changes the parameters of the interpolation filter (tap length, coefficients) based on motion characteristics and pixel location rather than applying uniform region-based filtering. This allows adaptive optimization of coding performance while controlling bandwidth usage by selecting appropriate filter strengths only where necessary.
Solution Approach 2:
The patent applies adaptive filtering selectively to specific pixels based on their distance from block boundaries and local motion characteristics, rather than applying region-based filtering to entire blocks. This partial application reduces the overall bandwidth requirement while maintaining coding performance in critical areas.
3Measurement precision
If longer-tap filter is used for all pixels, then interpolation accuracy is improved, but data access requirement increases
Solution Approach 1:
The patent applies longer-tap filters only to internal pixels that are farther from block boundaries where higher interpolation accuracy is beneficial, while using shorter-tap filters for boundary pixels where the available reference data is limited. This local differentiation improves overall accuracy without unnecessarily increasing data access requirements for all pixels.
Solution Approach 2:
The patent applies full-strength interpolation filtering only partially to pixels that truly benefit from it (internal pixels with sufficient reference data), rather than applying it uniformly to all pixels. This reduces the total data access requirement while maintaining interpolation accuracy where it matters most.
Data Source
AI summary
A method and apparatus provide adaptive interpolation filter for motion compensation with fractional-pixel accuracy. Embodiments of the present invention generate interpolated reference samples at non-integer locations based on existing reference samples in a reference block by using an interpolation filter set adaptively according to pixel location and/or pixel characteristics. A current block is then encoded or decoded using a temporal predictor including the interpolated reference samples. The adaptive interpolation filter can be applied to the prediction unit (PU). In one embodiment, the interpolation filter set consists of interpolation filters having different filter lengths. An interpolation filter with a longer tap length is applied to generate interpolated reference samples farther from the block boundary and an interpolation filter with a shorter tap length is applied to generate interpolated reference samples closer to the block boundary.