sacrifunk-loudness 0.1.1

ITU-R BS.1770 LUFS + true-peak + crest + LRA analyzer with batch CLI, Markdown report, and optional email send

sacrifunk-loudness

ITU-R BS.1770 LUFS + true-peak + crest analyzer with a Click CLI, Markdown report renderer, and optional SMTP email send. Drop a folder of WAV bounces at it and get back a JSON dump, a human-readable Markdown report, or an email straight to your inbox.

Why

Streaming-music mastering targets -14 LUFS ±0.5 and True Peak ≤ -1.0 dBTP (Sacrifunk's locked targets — same as Spotify/Apple/Tidal norms). Every bounce out of Logic Pro needs to clear those thresholds before it ships to CD Baby. This tool runs the standard analysis in one command and tells you which tracks pass and which need a second pass.

Install

pip install sacrifunk-loudness

Python 3.10+. Pulls in numpy, scipy, pyloudnorm, and click.

Usage

Single file

sacrifunk-loudness analyze Bounces/Darko_master.wav

Default output is JSON on stdout, summary on stderr.

Folder (recursive)

sacrifunk-loudness analyze Bounces/ --md report.md --json report.json

Custom targets (e.g. broadcast / podcast)

sacrifunk-loudness analyze Bounces/ \
  --target -16 \
  --tolerance 1.0 \
  --tp-limit -2 \
  --crest-min 10 --crest-max 22

Markdown from a saved JSON

sacrifunk-loudness report report.json --output report.md

Email a report

export SMTP_HOST=smtp.gmail.com
export SMTP_USER=[e-mail]
export SMTP_PASS='app-password-here'
export SMTP_FROM='Ahmed <[e-mail]>'

sacrifunk-loudness send report.md --to [e-mail] --subject "Genesis 3 — Blues Bang final master"

DSP

Metric	Method
Integrated loudness (LUFS)	pyloudnorm.Meter — ITU-R BS.1770-4 K-weighted gating
True peak (dBTP)	4× polyphase upsampling via scipy.signal.resample_poly, then 20·log10(max(abs(x)))
Sample peak (dBFS)	20·log10(max(abs(x))) on raw samples
Crest factor (dB)	sample_peak_dBFS − 20·log10(RMS)

Mono input is duplicated to stereo before measurement. Int16/Int24/Int32/uint8 WAVs are normalized to [-1, 1] float64.

Sacrifunk defaults

The default AnalysisTargets matches Sacrifunk mastering canon (locked April 22, 2026):

• LUFS target -14.0 ±0.5
• True peak ≤ -1.0 dBTP
• Crest factor 14–18 dB

Override any of these via CLI flags or by passing an AnalysisTargets to analyze_file() / analyze_folder() programmatically.

Library use

from sacrifunk_loudness import analyze_file, analyze_folder, render_markdown, SACRIFUNK_TARGETS

result = analyze_file("Bounces/Darko_master.wav")
print(result.lufs, result.true_peak_dbtp, result.verdict)

results = analyze_folder("Bounces/", SACRIFUNK_TARGETS, recursive=True)
md = render_markdown(results)

SMTP env vars

Var	Required	Default	Notes
SMTP_HOST	yes	—	e.g. smtp.gmail.com
SMTP_USER	yes	—	full email address
SMTP_PASS	yes	—	app password, not your Google login
SMTP_FROM	no	SMTP_USER	From: header
SMTP_PORT	no	587	use 465 for SSL providers
SMTP_SECURITY	no	starttls	starttls / ssl / none

Never pass credentials on the command line. send reads them from the environment only.

Development

pip install -e ".[dev]"
pytest -v

Tests use synthetic 1 kHz sine WAVs scaled to known LUFS levels via pyloudnorm — no Sacrifunk workspace dependency.

Roadmap

• LRA (Loudness Range, EBU R128 gated) — currently summary only.
• AAC / FLAC / AIFF input via soundfile fallback (today: WAV only via scipy.io.wavfile).
• HTML report alongside Markdown.
• --watch mode (chokidar-style folder watch).
• Optional Telegram digest output for mobile workflows.

The Sacrifunk production stack already runs the analyzer via an n8n cron at _logic_pro_bounce_watch (30s scheduler, Telegram digest to @Sacrifunkbot). A planned follow-up swaps runtime/scripts/wav_quick_analyze.py to a thin from sacrifunk_loudness.analyzer import analyze_file wrapper.

License

MIT — see LICENSE.