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.