Aulyzer *FREE* — Scientific Audio Measurement Instrument

Aulyzer is a cross-platform, command-line tool for detailed audio analysis. It is designed for engineers, researchers, and audio professionals who need to perform precise, repeatable measurements on audio files, either individually or in comparison to a reference. Aulyzer is built for unattended operation and automation through scripting.

Purpose

The primary purpose of Aulyzer is to provide a comprehensive suite of audio quality and characteristic metrics. It excels in two main scenarios:
- Single-File Analysis: Extracting a wide range of metrics from a single audio file to assess its properties. This is useful for quality control, file validation, and general signal characterization.
- Pairwise Comparison: Comparing one or more "probe" audio files against a "reference" file to quantify differences in level, time, and frequency domains. This is particularly useful for testing audio processing chains, evaluating codec quality, and ensuring signal integrity after any modification.

Key Features

- Comprehensive Measurements: Peak/true-peak (ISP), RMS, crest factor, DC offset, clipping statistics, activity analysis, bandwidth, spectral centroids, and more.
- Advanced Pairwise Comparison: Cross-correlation based lag detection, RMS and peak deltas, band-power differences, log-spectral distance, and frequency-response deviation metrics.
- Batch Processing: Feed one reference and many probes in a single command; each probe gets its own console and JSON report plus optional exports.
- Fragment Analysis: Target specific time ranges from each file without modifying the sources.
- Configurable Limits & Alerts: Attach min/max/delta constraints to nearly every measurement; out-of-range values are flagged in reports for automated QC pipelines.
- Optional Processing Steps: Controlled resampling, dithering, band-pass preparation, lag compensation, and compensated audio renders for deeper investigations.
- Extensive Parameter System: Every measurement, limit, action, and formatting option is addressable through `key=value` arguments. Run `aulyzer --list-params` to browse defaults.
- Flexible Reporting:
     * Console Output: Human-readable blocks with optional long descriptions or alert-only filtering.
     * JSON Export: Every run produces machine-readable JSON files under the report directory for downstream tooling.
- Visualization Outputs: Generates Gnuplot scripts and PNGs for waveform and spectrogram views with customizable palettes, fonts, and dimensions.
- Cross-Platform: Works in Windows and Linux.

Measurement Categories

Single-file metrics:
     - Duration & detected sample rate / bit depth (nominal and inferred true bit depth).
     - Peak and true-peak level with timestamps, RMS window statistics (peak/mean/min/total).
     - Crest-factor trace, frame power, spectral centroid, DC offset, clipping percentage, event counts, and click detection via abs-delta PCM.
     - Activity timing and bandwidth estimation when enabled.

Pairwise metrics:
     - Lag detection via cross-correlation with optional automatic compensation.
     - RMS difference vectors (abs/peak/mean/min/total) with optional level compensation.
     - Band-power deltas, log-spectral distance, per-band frequency-response deviation, and configurable export of aligned or EQ-adjusted probe WAVs.

Optional actions & exports:
     - Controlled resampling
     - Dither injection for single-file and pairwise flows
     - Waveform and spectrogram PNG creation with full styling control (by means of gnuplot script generation).
     - Intermediate audio renders: aligned probe/reference, frequency-response compensated probe, and filtered variants when requested.

Outputs & Artifacts

* Console report summarizing the reference, each probe, and pairwise comparison sections
* JSON reports for the reference and every probe comparison
* Optional PNG images and WAV intermediates
* Alerts clearly flagged when any measurement violates configured limits

Supported Formats & Requirements

* Input format: mono PCM WAV files using one of the supported sample rates (2 kHz - 192 kHz)
* Fragment notation: wrap file name and optional start/stop seconds in braces {"file.wav",start,stop}
* Multichannel files must be pre-converted to mono before analysis

Download

Windows: click to download (.ZIP)
Mac OS: available upon personal request for Intel and ARM silicone
Linux: available under commercial license

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Commercial inquiries

Get in touch: tools /at/ audiowatermarking.com