Crate halfband 

A high-performance 2x resampling library for audio signals using polyphase filters.

This crate provides two main approaches to resampling:

• Finite Impulse Response (FIR): Linear-phase windowed-sinc filters. These filters have a constant phase delay (latency) for all frequencies.
• Infinite Impulse Response (IIR): All-pass based recursive filters based on the HIIR library. These generally provide steeper filtering, lower latency and better performance, but the phase delay is not constant across the frequency range.

Both FIR and IIR provide Upsampler and Downsampler structs that have the same API.

Example

use halfband::fir;

let mut up = fir::Upsampler8::default();
let mut down = fir::Downsampler8::default();

let mut samples = vec![0.1, 0.2, 0.3];

for s in &mut samples {
    // Upsample: returns two high-rate samples
    let [mut s0, mut s1] = up.process(*s);

    // Apply nonlinearity (e.g., hard clipping or tanh)
    s0 = s0.tanh();
    s1 = s1.tanh();

    // Downsample: filters and returns one low-rate sample
    *s = down.process(s0, s1);
}

Modules

fir

Finite Impulse Response (FIR) polyphase resamplers.

iir

Infinite Impulse Response (IIR) polyphase resamplers.