Crate ruststft

source ·
Expand description

computes the short-time fourier transform on streaming data.

to use add ruststft = "*" to the [dependencies] section of your Cargo.toml and use ruststft; in your code.

example

use ruststft::{STFT, WindowType};

// let's generate ten seconds of fake audio
let sample_rate: usize = 44100;
let seconds: usize = 10;
let sample_count = sample_rate * seconds;
let all_samples = (0..sample_count).map(|x| x as f64).collect::<Vec<f64>>();

// let's initialize our short-time fourier transform
let window_type: WindowType = WindowType::Hanning;
let window_size: usize = 1024;
let step_size: usize = 512;
let mut stft = STFT::new(window_type, window_size, step_size);

// we need a buffer to hold a computed column of the spectrogram
let mut spectrogram_column: Vec<f64> =
    std::iter::repeat(0.).take(stft.output_size()).collect();

// iterate over all the samples in chunks of 3000 samples.
// in a real program you would probably read from something instead.
for some_samples in (&all_samples[..]).chunks(3000) {
    // append the samples to the internal ringbuffer of the stft
    stft.append_samples(some_samples);

    // as long as there remain window_size samples in the internal
    // ringbuffer of the stft
    while stft.contains_enough_to_compute() {
        // compute one column of the stft by
        // taking the first window_size samples of the internal ringbuffer,
        // multiplying them with the window,
        // computing the fast fourier transform,
        // taking half of the symetric complex outputs,
        // computing the norm of the complex outputs and
        // taking the log10
        stft.compute_column(&mut spectrogram_column[..]);

        // here's where you would do something with the
        // spectrogram_column...

        // drop step_size samples from the internal ringbuffer of the stft
        // making a step of size step_size
        stft.move_to_next_column();
    }
}

Structs

Enums

Traits

Functions

  • log10_positive
    returns 0 if log10(value).is_negative(). otherwise returns log10(value). log10 turns values in domain 0..1 into values in range -inf..0. log10_positive turns values in domain 0..1 into 0. this sets very small values to zero which may not be what you want depending on your application.