Crate ruststft 

ruststft

A complete short-time Fourier transform (STFT) toolkit for Rust:

• Forward STFT over real-valued signals, in both streaming and batch modes, backed by realfft (≈2× faster and half the memory of a full complex FFT on real input).
• Inverse STFT with weighted overlap-add (WOLA) for perfect reconstruction.
• A rich window library (Hann, Hamming, Blackman/-Harris, Nuttall, Bartlett, triangular, Welch, cosine, Tukey, Kaiser, Gaussian, flat-top) with both periodic (spectral-analysis) and symmetric (filter-design) variants.
• Spectrum helpers: magnitude, power, phase and decibel conversions.
• Optional mel spectrograms and MFCCs (mel feature).
• Optional ndarray I/O (ndarray), parallel batch processing (rayon) and configuration (de)serialization (serde).

Quick start (batch)

use ruststft::{Stft, Window};

// A 1 kHz tone sampled at 8 kHz.
let fs = 8_000.0;
let signal: Vec<f64> = (0..8_000)
    .map(|n| (2.0 * std::f64::consts::PI * 1_000.0 * n as f64 / fs).sin())
    .collect();

let mut stft = Stft::builder()
    .window(Window::<f64>::hann(1024))
    .hop_size(256)
    .build()
    .unwrap();

let spec = stft.spectrogram(&signal);
assert_eq!(spec.n_freqs(), 1024 / 2 + 1); // includes the Nyquist bin

Streaming

use ruststft::{Stft, Window};

let mut stft = Stft::builder()
    .window(Window::<f32>::hann(1024))
    .hop_size(512)
    .build()
    .unwrap();

let mut column = vec![num_complex::Complex::new(0.0f32, 0.0); stft.n_freqs()];
let chunk: Vec<f32> = (0..3000).map(|x| x as f32).collect();

stft.append(&chunk);
while stft.ready() {
    stft.process_into(&mut column).unwrap();
    // ... use `column` ...
    stft.step();
}

no_std

The crate is #![no_std] (with alloc). The FFT-backed processors (Stft, Istft, batch spectrograms) require the default std feature because the underlying FFT backend needs std. The window library, crate::mel filterbank/MFCC math and the crate::spectrum helpers build without std.

Re-exports

pub use error::StftError;

pub use sample::Sample;

pub use window::Symmetry;

pub use window::Window;

pub use window::WindowFunction;

Modules

error

Error type returned by the fallible parts of the crate.

melmel

Mel filterbank, (log-)mel spectrograms and MFCCs.

sample

Numeric scalar abstraction shared by the whole crate.

spectrum

Helpers for turning complex STFT coefficients into magnitudes, powers, phases and decibels.

window

Analysis/synthesis windows.

Structs

Complex

A complex number in Cartesian form.

Istftstd

An inverse short-time Fourier transform that reconstructs a real signal from spectrogram columns using weighted overlap-add.

IstftBuilderstd

Builder for Istft.

Spectrogramstd

A dense spectrogram stored frame-major: n_frames columns of n_freqs complex bins each.

Stftstd

A streaming forward short-time Fourier transform over real samples.

StftBuilderstd

Builder for Stft.

Enums

PadMode

How a signal is padded when centered framing is enabled in batch mode.

Scaling

How the complex STFT coefficients are scaled.