Audio Subband Window Interpolation for Low-Delay Filterbanks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern digital audio processing systems face challenges in balancing bit rate, computational complexity, memory requirements, quality, and delay, particularly in real-time applications, where compromises often need to be made across these parameters to achieve optimal performance.
Innovation Solution
The use of an interpolation scheme to derive a window function with a smaller number of window coefficients from a larger one, allowing for improved energy distribution and reduced memory usage, while maintaining quality and minimizing delay, is employed in both analysis and synthesis filterbanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger window function with more window coefficients is used, then audio quality and frequency response are improved, but memory requirements and computational complexity increase
Solution Approach 1:
The patent divides the audio signal processing into subband channels, where each subband uses a smaller, optimized window function. This segmentation allows the overall system to achieve high frequency response quality through multiple subbands while each individual subband consumes less memory, resolving the contradiction between overall frequency response quality and individual memory requirements.
Solution Approach 2:
The patent changes the window function parameters (size and coefficients) adaptively for different subband channels. By optimizing the window function parameters for each specific subband rather than using a single large window function for the entire audio signal, the system achieves high frequency response quality while reducing the memory requirements for storing window coefficients.
2Measurement precision
If a larger window function with more window coefficients is used, then audio quality and frequency response are improved, but computational complexity increases
Solution Approach 1:
The patent segments the audio signal into multiple subband channels, each processed with a smaller window function. This segmentation reduces the computational complexity of individual window operations while maintaining high overall frequency response quality through the combined processing of all subbands.
Solution Approach 2:
The patent optimizes window function parameters for each subband channel, using smaller window sizes appropriate for each subband's frequency characteristics. This adaptive parameter optimization reduces the computational complexity of window operations compared to using a single large window function, while maintaining high frequency response quality.
3Loss of time
If real-time processing is implemented with lower delay, then responsiveness is improved, but quality and memory requirements may be compromised
Solution Approach 1:
The patent processes audio signals in parallel subband channels, allowing independent processing of each subband with smaller data buffers. This segmentation enables reduced processing delay for real-time applications while maintaining audio quality through the combined reconstruction of all subbands, avoiding the need for large buffers that would increase delay.
4Loss of time
If real-time processing is implemented with lower delay, then responsiveness is improved, but memory requirements may increase to maintain quality
Solution Approach 1:
The patent divides the audio signal into subband channels, each requiring smaller memory buffers for processing. This segmentation reduces the total memory requirements compared to processing the entire audio signal with a single large buffer, while enabling faster processing with lower delay for real-time applications.
Data Source
AI summary
An embodiment of an apparatus for generating audio subband values in audio subband channels includes an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function including a sequence of window coefficients to obtain windowed samples. The analysis window function includes a first number of window coefficients derived from a larger window function including a sequence of a larger second number of window coefficients, wherein the window coefficients of the window function are derived by an interpolation of window coefficients of the larger window function. The apparatus further includes a calculator for calculating the audio subband values using the windowed samples.