Interpolated Audio Subband Windowing for Low-Delay Quality
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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 in these parameters to achieve optimal performance.
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
1Measurement precision
If a larger window function with more coefficients is used, then audio quality is improved, but delay increases and computational complexity increases
Solution Approach 1:
The patent divides the audio signal processing into subband channels, where each subband channel uses a smaller window function with fewer coefficients. This segmentation allows the overall system to achieve good audio quality through multi-channel processing while each individual channel maintains low delay and computational complexity.
Solution Approach 2:
The patent transitions from using a single large window function in the time domain to using multiple smaller window functions across frequency subbands. This dimensional change from time-domain to frequency-subband domain enables achieving both low delay and good quality simultaneously by distributing the processing across multiple frequency channels.
2Measurement precision
If a larger window function with more coefficients is used, then audio quality is improved, but computational complexity increases
Solution Approach 1:
The patent segments the audio signal into multiple subband channels, with each channel processed using a smaller window function. This division reduces the computational burden on each processing unit while maintaining overall audio quality through the combined output of all subband channels.
Solution Approach 2:
The patent applies partial action by using smaller window functions that are sufficient for each individual subband channel rather than applying one large window function to the entire audio signal. This partial processing approach reduces computational complexity while achieving the necessary quality through multi-channel synthesis.
3Measurement precision
If a larger window function with more coefficients is used, then audio quality is improved, but memory requirements increase
Solution Approach 1:
The patent divides the window function coefficients into multiple smaller sets, one for each subband channel. This segmentation reduces the memory footprint for storing window coefficients while maintaining audio quality through the distributed processing architecture across multiple frequency channels.
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.