Python-SoXR#
High quality, one-dimensional sample-rate conversion library for Python.
Homepage: dofuuz/python-soxr
Documentation: https://python-soxr.readthedocs.io
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, # 1D(mono) or 2D(frames, channels) array input
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, # 1D(mono) or 2D(frames, channels) array input
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, …])
Requirement#
x86 and ARM processors are supported.
Neon extension is required for ARM CPUs. Without Neon, it may crash or return inaccurate result.
Benchmark#
Sweep, impulse, speed compairsion with other Python resamplers.
https://colab.research.google.com/drive/1XgSOvWlRIau1FYwQG_yRSAhDK3KB8bEL?usp=sharing
Speed comparison summary#
Downsampling 10 sec of 48000 Hz to 44100 Hz.
Ran on Google Colab.
Library |
Time on CPU (ms) |
---|---|
soxr (HQ) |
7.2 |
scipy.signal.resample |
13.4 |
soxr (VHQ) |
15.8 |
torchaudio |
19.2 |
lilfilter |
21.4 |
julius |
23.1 |
resampy (kaiser_fast) |
62.6 |
samplerate (sinc_medium) |
92.5 |
resampy (kaiser_best) |
256 |
samplerate (sinc_best) |
397 |
Technical detail#
For technical details behind resampler, see libsoxr docs.
Python-SoXR uses forked version of libsoxr. See difference here.
These changes does not apply to dynamic linked builds(e.g. conda-forge build)
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.