audacity

SoX Resampler Library       Copyright (c) 2007-12 robs@users.sourceforge.net

The SoX Resampler library performs one-dimensional sample-rate conversion.
It may be used, for example, to resample PCM-encoded audio.  For higher-
dimensional resampling, such as for visual-image processing, you should look
elsewhere.

Its aim is to provide fast, high-quality resampling.  At its highest quality
settings, it can produce 32-bit-perfect results with signal occupied-
bandwidths of up to 98%.¹  Resampling ratios can be any (floating point)
value between +/- 8 octaves.

Depending on how the resampler is configured, quality may be traded for
speed, but only to a certain extent: there may be faster, average-quality
resamplers available.  Multi-channel resampling can be configured to use
multiple CPU-cores, thus reducing execution time (with a slight expense of
CPU-cycles).

The resampler is currently available either as part of `libsox' (the audio
file-format and effect library), or stand-alone as `libsoxr' (this package).

The APIs of libsox and libsoxr are slightly different, with that of libsoxr
designed specifically for resampling.  An application requiring support for
other effects, or for reading-from or writing-to audio files or devices, can
use libsox (or other libraries such as libsndfile or libavformat).

Applications may use either floating-point or integer sample formats, and,
in the case of multiple channels, either channel-interleaved, or split-
channels.

The libsoxr API is currently documented in the header file `soxr.h' and by
example code in the 'examples' directory.

For compatibility with the popular `libsamplerate' library, the header file
`soxr-lsr.h' is provided and may be used as an alternative API. For details
of that API, see http://www.mega-nerd.com/SRC/api.html.  Note however, that
libsoxr does not provide a full emulation of libsamplerate; in particular,
`vari-speeding' is not currently supported.

For build and installation instructions, see the file `INSTALL'; for
copyright and licensing information, see the file `copyright'.

The resampler was inspired by Laurent De Soras' paper `The Quest For The
Perfect Resampler', http://ldesoras.free.fr/doc/articles/resampler-en.pdf.

¹ Note that no practical resampler can be bit-perfect to 100% bandwidth.