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Author: Magnus Bro Kolstø, Iver Jordal

Requires Python: >=3.10

Classifiers

loudness

A Python package (battle-tested C++ under the hood) for calculating integrated loudness (LUFS) with the ITU BS.1770 loudness algorithm. Useful for EBU R 128 compliance. Takes NumPy arrays as input (supports mono and stereo/multichannel). Based on libloudness (original implementation by Magnus Bro Kolstø, Nomono).

Installation

pip install loudness

Usage example

import soundfile as sf
import loudness

audio, sr = sf.read("audio.wav", dtype="float32")  # shape (samples, channels)
lufs = loudness.integrated_loudness(audio, sr)
print(f"{lufs:.2f} LUFS")

Performance

loudness is significantly faster than the alternatives when running on CPU:

Execution time comparison: loudness 0.1.0: 0.056s, pyebur128 0.1.1: 0.096s, torchaudio 2.8.0: 0.282, pyloudnorm 0.1.1: 0.293s, pyloudness 1.1.2: 0.581s

Changelog

[0.2.0] - 2025-12-26

Added

Add support for Python 3.14

Removed

Remove support for Python 3.9

For the complete changelog, go to CHANGELOG.md

Development setup

Install CMake and a C++ compiler
pip install numpy pybind11 build scikit-build-core
python -m build --wheel
Install the built wheel
pytest

Alternatives (Python)

Name	Github stars	License	Last commit
jaxloudnorm
loudness
PALA
pyebur128
pyloudness
pyloudnorm
torchaudio

0.2.0 Dec 26, 2025

0.1.0 Jul 21, 2025

Wheel compatibility matrix

Platform	CPython 3.10	CPython 3.11	CPython 3.12	CPython 3.13	CPython 3.14
macosx_11_0_arm64
manylinux_2_24_aarch64
manylinux_2_24_x86_64
manylinux_2_28_aarch64
manylinux_2_28_x86_64
musllinux_1_2_aarch64
musllinux_1_2_x86_64
win_amd64

Files in release

loudness-0.2.0-cp310-cp310-macosx_11_0_arm64.whl (94.3KiB)

loudness-0.2.0-cp310-cp310-manylinux_2_24_aarch64.manylinux_2_28_aarch64.whl (107.1KiB)

loudness-0.2.0-cp310-cp310-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl (116.5KiB)

loudness-0.2.0-cp310-cp310-musllinux_1_2_aarch64.whl (1.0MiB)

loudness-0.2.0-cp310-cp310-musllinux_1_2_x86_64.whl (1.1MiB)

loudness-0.2.0-cp310-cp310-win_amd64.whl (96.0KiB)

loudness-0.2.0-cp311-cp311-macosx_11_0_arm64.whl (95.7KiB)

loudness-0.2.0-cp311-cp311-manylinux_2_24_aarch64.manylinux_2_28_aarch64.whl (108.4KiB)

loudness-0.2.0-cp311-cp311-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl (118.6KiB)

loudness-0.2.0-cp311-cp311-musllinux_1_2_aarch64.whl (1.0MiB)

loudness-0.2.0-cp311-cp311-musllinux_1_2_x86_64.whl (1.1MiB)

loudness-0.2.0-cp311-cp311-win_amd64.whl (96.8KiB)

loudness-0.2.0-cp312-cp312-macosx_11_0_arm64.whl (95.9KiB)

loudness-0.2.0-cp312-cp312-manylinux_2_24_aarch64.manylinux_2_28_aarch64.whl (108.9KiB)

loudness-0.2.0-cp312-cp312-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl (118.5KiB)

loudness-0.2.0-cp312-cp312-musllinux_1_2_aarch64.whl (1.0MiB)

loudness-0.2.0-cp312-cp312-musllinux_1_2_x86_64.whl (1.1MiB)

loudness-0.2.0-cp312-cp312-win_amd64.whl (97.7KiB)

loudness-0.2.0-cp313-cp313-macosx_11_0_arm64.whl (95.9KiB)

loudness-0.2.0-cp313-cp313-manylinux_2_24_aarch64.manylinux_2_28_aarch64.whl (110.3KiB)

loudness-0.2.0-cp313-cp313-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl (118.3KiB)

loudness-0.2.0-cp313-cp313-musllinux_1_2_aarch64.whl (1.0MiB)

loudness-0.2.0-cp313-cp313-musllinux_1_2_x86_64.whl (1.1MiB)

loudness-0.2.0-cp313-cp313-win_amd64.whl (97.7KiB)

loudness-0.2.0-cp314-cp314-macosx_11_0_arm64.whl (96.2KiB)

loudness-0.2.0-cp314-cp314-manylinux_2_24_aarch64.manylinux_2_28_aarch64.whl (110.4KiB)

loudness-0.2.0-cp314-cp314-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl (118.4KiB)

loudness-0.2.0-cp314-cp314-musllinux_1_2_aarch64.whl (1.0MiB)

loudness-0.2.0-cp314-cp314-musllinux_1_2_x86_64.whl (1.1MiB)

loudness-0.2.0-cp314-cp314-win_amd64.whl (99.8KiB)

loudness-0.2.0.tar.gz (748.6KiB)

Extras: None

Dependencies:

numpy (<3,>=1.22)