A collection of useful C++ classes for digital signal processing. [MIT]

A Fast Fourier Transform (FFT) library that tries to Keep it Simple, Stupid. [BSD-3-Clause]

IIR Realtime C++ filter library. [MIT]

C implementation of 1D and 2D wavelet transforms. [BSD-3-Clause]

FFT implementation based on FFTPack, but with several improvements. [BSD-3-Clause]

A C library for computing the DFT in one or more dimensions. [GPL]