Audio Resampling Interpolation for Low-Delay Signal Quality
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Solution Overview
Problem
Current audio frequency resampling methods, such as polynomial interpolation and FIR filtering, face challenges in maintaining signal quality and reducing complexity, especially when increasing interpolation order beyond 3, which results in higher complexity and limited performance improvements for real signals.
Innovation Solution
A method for resampling audio frequency signals using a weighted average of interpolation values computed over multiple intervals, allowing for efficient interpolation with reduced complexity while achieving better signal-to-noise ratios, particularly for high-frequency zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polynomial interpolation of order higher than 3 is used, then interpolation precision is improved, but computational complexity increases excessively
Solution Approach 1:
The patent divides the interpolation process into multiple intervals (typically 3 intervals: left, center, right) and computes interpolation values separately for each interval using lower-order polynomials (e.g., cubic interpolation). The final interpolated value is obtained by computing a weighted average of these interval-specific interpolation values. This segmentation allows maintaining high precision through multiple intervals while keeping the computational complexity of each individual interval manageable.
Solution Approach 2:
The patent applies different interpolation strategies to different local regions (intervals) of the signal. By computing interpolation values locally for each interval and then combining them with appropriate weights, the method achieves high overall precision without requiring a single high-order polynomial that would be computationally expensive. Each local interval uses a simpler interpolation model suited to its specific characteristics.
2Reliability
If FIR filtering is used for resampling, then signal quality is maintained, but algorithmic delay increases
Solution Approach 1:
The patent applies partial action by using multiple intervals rather than a single comprehensive high-order interpolation. This partial approach across several intervals achieves signal quality comparable to or better than FIR filtering, while avoiding the significant algorithmic delay that would result from using a long FIR filter impulse response. The method performs sufficient interpolation action locally in each interval without the excessive delay of global FIR filtering.
3Device complexity
If subband coding is used to reduce coding complexity, then coding complexity is reduced, but algorithmic delay increases
Solution Approach 1:
The patent segments the frequency spectrum into multiple subbands and processes each subband separately with appropriate interpolation. This segmentation approach maintains the coding complexity reduction benefit of subband processing while minimizing algorithmic delay by using efficient local interpolation methods in each subband, avoiding the need for long filter banks that would introduce significant delay.
Data Source
AI summary
A method is provided for resampling an audio-frequency signal in an audio-frequency signal encoding or decoding operation. The resampling is carried out by a method of interpolation of an order greater than one. The method is such that the interpolated samples are obtained by calculating a weighted average of possible interpolation values calculated over a plurality of intervals covering the time location of the sample to be interpolated. A resampling device is provided, which implements the method, and also an encoder and decoder including at least one resampling device.