Audio Subband Window Interpolation for Low-Delay Signal Processing
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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.
Innovation Solution
The use of an interpolation scheme to derive a window function with a smaller number of coefficients from a larger one, allowing for improved energy distribution of window coefficients, which reduces delay and increases quality while maintaining computational efficiency and memory savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a larger window function with more coefficients is used, then audio quality and energy distribution are improved, but computational complexity and memory requirements increase
Solution Approach 1:
The patent divides the window function into multiple segments or blocks, processing audio data in smaller chunks rather than applying a single large window function to the entire frame. This segmentation reduces the computational burden per operation while maintaining the quality benefits through multiple smaller transformations.
Solution Approach 2:
The patent transforms the audio signal from the time domain to the frequency domain using the window function, then processes different frequency bands separately. This dimensional transformation allows quality improvement in the frequency representation while reducing computational complexity by working with decoupled frequency components rather than the full time-domain signal.
2Manufacturing precision
If a larger window function with more coefficients is used, then audio quality and energy distribution are improved, but memory requirements increase
Solution Approach 1:
The patent divides the window function into multiple segments or blocks, processing audio data in smaller chunks rather than applying a single large window function to the entire frame. This segmentation reduces the computational burden per operation while maintaining the quality benefits through multiple smaller transformations.
Solution Approach 2:
The patent applies different window function coefficients to different portions or segments of the audio frame, allowing optimized memory usage by loading only the necessary coefficient subsets required for each processing stage rather than storing the entire large window function in memory simultaneously.
3Productivity
If real-time processing is implemented with standard coding schemes, then processing speed is improved, but delay is reduced only at the cost of higher bit rates
Solution Approach 1:
The patent pre-calculates and stores certain transformation parameters, basis functions, or window coefficients that are commonly used in audio processing. By preparing these elements in advance, the real-time processing stage requires fewer computations, achieving both low delay and efficient processing speed without increasing bit rate.
Solution Approach 2:
The patent dynamically adjusts processing parameters such as frame size, window function selection, or transformation depth based on the specific audio content and processing requirements. This adaptive parameter change allows optimization of the trade-off between processing speed and delay for different audio scenarios without requiring consistently high bit rates.
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.