The SoX Resampler library (libsoxr) performs one-dimensional
sample-rate conversion.  It may be used, for example, to resample
PCM-encoded audio.

It aims to give fast and high quality results for any constant
(rational or irrational) resampling ratio. Phase-response, preserved
bandwidth, aliasing, and rejection level parameters are all
configurable; alternatively, simple `preset' configurations may be
selected. An experimental, variable-rate resampling mode of operation
is also included.