Aulyzer – a new cross-platform command-line tool for scientific audio analysis.
Aulyzer was originally built as an internal lab instrument for validating audio watermarking, fingerprinting, and various processing chains. We are now releasing it as a standalone tool for engineers, researchers, and audio professionals who need precise, repeatable measurements on audio files.
What Aulyzer Is
Aulyzer is a command-line audio analyzer designed for:
- Single-file analysis – extracting a rich set of metrics from one audio file (quality control, characterization, validation).
- Pairwise comparison – comparing one or more “probe” files against a “reference” file to quantify differences in level, time, and frequency domains.
It is not a “pretty GUI” spectrum viewer. It’s a measurement instrument: deterministic, scriptable, and designed to integrate into automated workflows and test benches.
Core Use Cases
Typical scenarios where Aulyzer is useful:
- Codec / processing evaluation
Compare original vs. processed audio (codecs, streaming pipelines, DSP chains) and quantify: Level differences, Time alignment / lag, Band-power and spectral changes - Production & Broadcast QC
Run automated checks on delivered content to verify: Peak / true-peak limits, RMS levels - Algorithm & Product Testing
Validate new DSP algorithms, devices, or firmware by running repeatable batch tests against reference material and collecting machine-readable JSON results.
Key Features at a Glance
1. Comprehensive Measurements (Single File)
Aulyzer computes a wide range of metrics, including:
- Duration, detected sample rate, nominal and inferred bit depth
- Peak and true-peak (ISP) levels with timestamps
- RMS statistics (peak / mean / min / total)
- Crest factor traces, frame power, spectral centroid
- DC offset, clipping percentage and counts
- Click detection via abs-delta PCM
- Activity timing and bandwidth estimation (when enabled)
2. Advanced Pairwise Comparison (Reference vs Probe)
When you provide a reference and one or more probes, Aulyzer can:
- Detect lag via cross-correlation (with optional automatic lag compensation)
- Compute RMS and peak deltas (abs/peak/mean/min/total) with optional level compensation
- Compare band-power across frequency bands
- Evaluate log-spectral distance and per-band frequency-response deviation
- Optionally render aligned / EQ-compensated probe WAVs for listening checks
3. Batch & Fragment Analysis
- Process one reference vs many probes in a single command.
- Target specific time fragments per file using simple notation:
{"file.wav",start,stop}– without touching the original files.
4. Configurable Limits & Alerts
Almost every measurement can have: .min, .max, .delta_min, .delta_max
When limits are violated, Aulyzer flags alerts in both console and JSON reports – ideal for automated QC pipelines and CI systems.
5. Output & Reporting
- Console output – human-readable blocks, with optional “alerts-only” mode.
- JSON export – every run produces structured JSON in a report directory (default:
res/), ready for further parsing or dashboards. - Visualization – Aulyzer can generate Gnuplot scripts + PNGs: Waveform plots, spectrograms (customizable palettes, size, fonts)
6. Optional Processing & Tools
- Controlled resampling (single and pairwise flows)
- Optional dither injection
- Band-pass preparation
- Lag-compensated or frequency-response-compensated audio renders for deeper investigation.
Download Aulyzer: http://audiowatermarking.com/aulyzer