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
- 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, # 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.
- https://sourceforge.net/p/soxr/wiki/Home/
- http://sox.sourceforge.net/SoX/Resampling
- https://sourceforge.net/p/soxr/code/ci/master/tree/src/soxr.h
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.