dsp-audio-metrics

Pure numpy/scipy BS.1770-4 loudness metering and audio analysis for Python.

Measures integrated loudness (LUFS), loudness range (LRA), true peak (dBTP) per ITU-R BS.1770-4 / EBU R128, plus spectral balance, stereo-width and level helpers — with zero dependencies beyond numpy and scipy.

Install

pip install dsp-audio-metrics

Quick start

import numpy as np
import dsp_audio_metrics as dm

sr = 44100
t = np.arange(sr * 60) / sr
programme = 0.5 * np.sin(2 * np.pi * 997 * t)

res = dm.measure(programme, sr)
print(res.integrated_lufs)      # ~ -9.0 LUFS
print(res.true_peak_db)         # ~ -6.0 dBTP
print(res.gain_to_target_db)    # gain to hit -14 LUFS

normalized = dm.normalize_loudness(programme, sr, target_lufs=-14.0)

API

Loudness (BS.1770-4 / EBU R128)

Analysis

All functions accept mono (n,), (n, 1), stereo (n, 2) or multichannel (n, c) input and internally resample to the 48 kHz rate the standards mandate, so 44.1 kHz files are measured correctly.

Why this package

• Correct: every loudness path follows BS.1770-4 (48 kHz measurement rate, K-weighting, two-stage gating, 4×-or-more true-peak oversampling).
• Honest: silence is -inf, unmeasurable LRA is NaN — no fake 0.0.
• Small: two hard dependencies, ~400 lines, no audio I/O, no UI.

References

• ITU-R BS.1770-4 — Algorithms to measure audio programme loudness and true-peak audio level
• EBU Tech 3341 / R128 — Loudness normalisation and permitted maximum level

License

Apache-2.0