Python-SoXR

High quality, one-dimensional sample-rate conversion library for Python.

• Homepage: https://github.com/dofuuz/python-soxr
• Documentation: https://python-soxr.readthedocs.io
• Release Notes: https://github.com/dofuuz/python-soxr/releases
• PyPI: https://pypi.org/project/soxr/

Keywords: Resampler, Audio resampling, Samplerate conversion, DSP(Digital Signal Processing)

Python-SoXR is a Python wrapper of libsoxr.

Installation

pip install soxr

If installation fails, upgrade pip with python -m pip install --upgrade pip and try again.

in Conda environment

conda install -c conda-forge soxr-python

Note: Conda packge name is soxr-python, not python-soxr.

Basic usage

import soxr

y = soxr.resample(
    x,          # input array – mono(1D) or multi-channel(2D of [frame, channel])
    48000,      # input samplerate
    16000       # target samplerate
)

If input is not numpy.ndarray, it will be converted to numpy.ndarray(dtype='float32').
dtype should be one of float32, float64, int16, int32.

Output is numpy.ndarray with same dimension and data type of input.

Streaming usage

Use ResampleStream for real-time processing or very long signal.

import soxr

rs = soxr.ResampleStream(
    44100,              # input samplerate
    16000,              # target samplerate
    1,                  # channel(s)
    dtype='float32'     # data type (default = 'float32')
)

eof = False
while not eof:
    # Get chunk
    ...

    y_chunk = rs.resample_chunk(
        x,              # input aray – mono(1D) or multi-channel(2D of [frame, channel])
        last=eof        # Set True at end of input
    )

Output frame count may not be consistent. This is normal operation.
(ex. [0, 0, 0, 186, 186, 166, 186, 186, 168, ...])

📝 More code examples

Benchmark

Sweep, impulse, speed compairsion with other resamplers for Python.

https://colab.research.google.com/drive/1_xYUs00VWYOAXShB85W1MFWaUjGHfO4K?usp=sharing

Speed comparison summary

Downsampling 10 sec of 48000 Hz to 44100 Hz.
Ran on Google Colab.

Technical detail

For technical details behind resampler, see libsoxr docs.

• https://sourceforge.net/p/soxr/wiki/Home/
• http://sox.sourceforge.net/SoX/Resampling (archive)
• https://sourceforge.net/p/soxr/code/ci/master/tree/src/soxr.h

Python-SoXR package comes with modified version of libsoxr. See changes here.
These changes do not apply to dynamic-linked builds (e.g. conda-forge build).
To check the version of libsoxr, use soxr.__libsoxr_version__.

Credit and License

Python-SoXR is LGPL v2.1+ licensed, following libsoxr's license.

OSS libraries used

libsoxr (LGPLv2.1+)

The SoX Resampler library
https://sourceforge.net/projects/soxr/

Python-SoXR is a Python wrapper of libsoxr.

PFFFT (BSD-like)

PFFFT: a pretty fast FFT.
https://bitbucket.org/jpommier/pffft/

libsoxr dependency.