pitch-core

Streaming pitch (f0) tracker for Rust. Three pure-DSP backends behind one trait. No model files. No GPU. No ONNX Runtime.

use pitch_core::{PitchTracker, SwipeEstimator};

let est = SwipeEstimator::new()?;                        // 96.4% RPA on MIR-1K
let mut tracker = PitchTracker::new(est, 48_000, 1024)?;

for chunk in mic_chunks {
    for f in tracker.process(&chunk)? {
        if f.confidence > 0.3 {
            println!("{:6.3}s  {:6.1} Hz  conf={:.2}",
                     f.time_s, f.pitch_hz, f.confidence);
        }
    }
}

Add to Cargo.toml:

[dependencies]
pitch-core = "0.1"

For neural backends (CREPE, RMVPE, SwiftF0, FCPE; PESTO behind feature) add the companion crate pitch-core-onnx.

Backends

algorithm	constructor	target rate	hop	latency	notes
SWIPE'/SWIPE	`SwipeEstimator::new()` (Balanced) / `with_max_window()`	48 kHz	10 ms	85 / 170 / 340 ms	strongest pure-DSP option; wraps `swipe-rs`
pYIN	`PyinEstimator::new()`	48 kHz	20 ms	~333 ms (batched)	conservative voicing — high precision, low recall; wraps `pyin`
Praat-AC	`PraatAcEstimator::new(markov_step: bool)`	48 kHz	20 ms	~43 ms	Boersma 1993, original FFT impl; cheap & fast for speech

All three implement the [PitchEstimator] trait and slot into [PitchTracker] interchangeably. The trait surface is small enough that custom backends are trivial to add — see examples/custom_backend.rs.

Streaming model

Feed mono f32 audio at the host sample rate via [PitchTracker::process]. A built-in linear resampler converts to the backend's target rate, the backend buffers internally, and process returns whatever frames are ready. An empty Vec is returned while the backend is filling its first window — that's normal at the start of the stream and after reset.

PitchFrame::is_preliminary is reserved for backends that emit edge-of-buffer estimates twice (preliminary + settled). None of the DSP backends in this crate do; SwiftF0 in pitch-core-onnx does.

Acknowledgements

A. Camacho & J. G. Harris — SWIPE/SWIPE' (JASA 2008)
D. Marttila & J. D. Reiss — multi-resolution mel-axis SWIPE (ISMIR 2025)
M. Mauch & S. Dixon — pYIN (ICASSP 2014)
P. Boersma — autocorrelation-with-window-AC method (Praat, 1993)
Sytronik — pyin Rust crate

Authors

Created and maintained by gzivdo — design, architecture, research direction, and code review.

Co-author (implementation): Claude Opus 4.7 (Anthropic), under gzivdo's direction. AI is not a copyright holder; copyright is held entirely by the human maintainer (per US Copyright Office guidance, Jan 2025).

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option. Algorithms themselves are not copyrightable (US §102(b); Feist v. Rural, 1991; EU Directive 2009/24/EC) — all Rust code in this crate is independent reimplementation or original glue.