praatfan-rust

Fast Rust implementation of Praat's core acoustic analysis algorithms, with Python bindings. MIT-licensed.

praatfan_rust is the compiled backend for praatfan — a clean-room reimplementation of Praat's acoustic analysis, written from published papers and Praat's public documentation rather than from Praat's GPL source, so it can be used under a permissive licence.

pip install praatfan-rust

It can be used directly, or installed alongside praatfan and selected automatically through that package's unified API.

What it computes

Audio is read via Symphonia (WAV, FLAC, MP3, OGG/Vorbis and ADTS AAC; not AIFF or CAF). NIST SPHERE, including shorten-compressed, decodes through a statically linked desphere — no extra dependency and no external binary. Mono only; multi-channel files require an explicit channel selection.

Example

import praatfan_rust

sound = praatfan_rust.Sound("audio.wav")

pitch = sound.to_pitch_ac(time_step=0.01, pitch_floor=75.0, pitch_ceiling=600.0)
formant = sound.to_formant_burg(time_step=0.0, max_number_of_formants=5,
                                maximum_formant=5500.0)
harmonicity = sound.to_harmonicity_ac(0.01, 75.0, 0.1, 4.5)

Threading

Per-frame analysis (pitch, harmonicity, intensity, formants, spectrogram) and the resampler run on all CPU cores, with results bit-identical to a single-threaded run. Since 0.1.14 results are also the same on every machine: maths functions come from the pure-Rust libm crate and FFTs from a vendored FFTPACK port, so nothing depends on the host's maths library or on CPU features detected at run time. Set RAYON_NUM_THREADS before the first analysis to limit the thread count, e.g. 1 when you already parallelise across processes. The GIL is released during analyses, and the library is safe to use in multiprocessing children started with fork. The WebAssembly build is single-threaded.

Reading harmonicity values

Two entries in an HNR contour are markers rather than measurements:

• -200 — no periodicity was found (silence, DC, unvoiced).
• NaN — the correlation is not resolvable from 1, so no HNR can be derived.

Filter both before averaging, e.g. v[np.isfinite(v) & (v > -200)]. The autocorrelation method also requires periods_per_window >= 3.0; below that the estimator is ill-conditioned and emits a FutureWarning (this will become an error in a future release). 4.5 is the standard value for the AC method; 1.0 is the CC default, not an AC one.

Also available

• WebAssembly — the same core runs in the browser via wasm-pack.
• praatfan-open-pipe — a JSON-over-stdin/stdout binary used by the R package, so R and shell callers pay the audio load once per file.

Links

• Source, documentation and issues: https://github.com/ucpresearch/praatfan-core-clean
• Pure-Python sibling: https://pypi.org/project/praatfan/

Licence

MIT. The wheel also contains third-party code (MIT, Apache-2.0, BSD, Zlib, Unicode-3.0, and the MPL-2.0 symphonia decoders, unmodified); their notices are in the wheel's LICENSE-THIRD-PARTY file.