https://github.com/sigurd4/real_time_fir_iir_filters
Real-time FIR and IIR filters designed for use with vst's
https://github.com/sigurd4/real_time_fir_iir_filters
audio butterworth-filter chebyshev-filter elliptic-filter finite-impulse-response fir high-pass-filter iir infinite-impulse-response low-pass-filter rc-filter real-time sallen-key-filter signal-processing vst
Last synced: about 1 month ago
JSON representation
Real-time FIR and IIR filters designed for use with vst's
- Host: GitHub
- URL: https://github.com/sigurd4/real_time_fir_iir_filters
- Owner: sigurd4
- License: mit
- Created: 2022-12-10T01:27:30.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2025-04-03T16:55:45.000Z (about 2 months ago)
- Last Synced: 2025-04-03T17:37:45.969Z (about 2 months ago)
- Topics: audio, butterworth-filter, chebyshev-filter, elliptic-filter, finite-impulse-response, fir, high-pass-filter, iir, infinite-impulse-response, low-pass-filter, rc-filter, real-time, sallen-key-filter, signal-processing, vst
- Language: Rust
- Homepage: https://crates.io/crates/real_time_fir_iir_filters
- Size: 3.83 MB
- Stars: 3
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/build-nightly.yml)
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/build-nightly-all-features.yml)
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/build-stable.yml)
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/build-stable-all-features.yml)
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/test.yml)
[](https://github.com/sigurd4/real_time_fir_iir_filters/actions/workflows/lint.yml)
[](https://crates.io/crates/real_time_fir_iir_filters)
[](https://opensource.org/licenses/MIT)
[](https://docs.rs/real_time_fir_iir_filters)
[](https://app.codecov.io/github/sigurd4/real_time_fir_iir_filters)
# real_time_fir_iir_filters
Ever needed a low pass filter for your VST? This crate has a wide selection of filters for real-time usage. It's designed to have as little runtime overhead as possible.
## How does it work?
Everything that can be computed at compile-time, will be, and the filter coefficients will be cached as well.
I then use the following algorithm to process the signal with as few steps as possible given the filter's coefficients:
(The figure is from: Alan V. Oppenheimer & Ronald W. Schafer - Discrete-Time Signal Processing)
## Example
```rust
use core::f64::consts::TAU;
use real_time_fir_iir_filters::{
conf::LowPass,
param::OmegaEpsilonXi,
rtf::Rtf,
filters::iir::second::SecondOrderEllipticFilter
};
// Initialize a 2. order elliptic low-pass filter at 440Hz
let mut filter = SecondOrderEllipticFilter::new::(
OmegaEpsilonXi {
omega: 440.0*TAU,
epsilon: 0.5,
xi: 1.5
}
);
const N: usize = 10;
const RATE: f64 = 8000.0;
{
// Unit impulse
let mut imp_resp = [0.0; N];
imp_resp[0] = 1.0;
// Apply filter to imp_resp
for x in &mut imp_resp
{
[*x] = filter.filter(RATE, *x);
}
// Prints the impulse response of the filter.
println!("h[n] = {:?}", imp_resp);
}
// Resets internal state of filter to zero
filter.reset();
{
// Generate frequency response for ω ∈ [0, 2π)
let freq_resp = core::array::from_fn::<_, N, _>(|i| {
let omega = i as f64/N as f64*TAU;
filter.frequency_response(RATE, omega)
});
println!("H = {:?}", freq_resp);
}
```
## Available filters
| Order | Filter | Parameterization | Configuration |
|-------|--------------------------------|--------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
| 1 | `FirstOrderAllPassFilter` | `Tau` | `AllPass` |
| 1 | `FirstOrderFilter` | `Omega` `RC` `LR` | `LowPass` `HighPass` |
| 1 | `FirstOrderLRFilter` | `LR` | `LowPass` `HighPass` |
| 1 | `FirstOrderRCFilter` | `RC` | `LowPass` `HighPass` |
| 1 | `PIFilter` | `PI` | - |
| 2 | `PIDFilter` | `PI` `PID` | - |
| 2 | `SecondOrderButterworthFilter` | `Omega` | `LowPass` `Peak` `HighPass` |
| 2 | `SecondOrderChebyshev1Filter` | `Omega` `OmegaEpsilon` | `LowPass` `HighPass` |
| 2 | `SecondOrderChebyshev2Filter` | `Omega` `OmegaEpsilon` | `LowPass` `HighPass` |
| 2 | `SecondOrderEllipticFilter` | `Omega` `OmegaEpsilon` `OmegaEpsilonXi` | `LowPass` `HighPass` |
| 2 | `SecondOrderFilter` | `Omega` `OmegaZeta` | `LowPass` `Peak` `HighPass` |
| 2 | `SecondOrderRCFilter` | `RC` `RC2` | `LowPass` `BandPass<1>` `BandPass<2>` `HighPass` |
| 2 | `SecondOrderRLCFilter` | `RC` `LR` `RLC` | `LowPass` `BandStop` `BandPass` `HighPass` |
| 2 | `SecondOrderSallenKeyFilter` | `RC2SallenKey` `RC2GSallenKey` | `LowPass` `BandPass<1>` `BandPass<2>` `HighPass` |
| 3 | `ThirdOrderButterworthFilter` | `Omega` | `LowPass` `Peak<1>` `Peak<2>` `HighPass` |
| 3 | `ThirdOrderFilter` | `Omega` `OmegaZeta` `Omega2Zeta` | `LowPass` `Peak<1>` `Peak<2>` `HighPass` |
| 3 | `ThirdOrderSallenKeyFilter` | `RC` `RC2SallenKey` `RC2GSallenKey` `RC3SallenKey` `RC3GSallenKey` | `LowPass` `BandPass<1>` `BandPass<2>` `BandPass<3>` `BandPass<4>` `BandPass<5>` `BandPass<6>` `HighPass` |
| 4 | `WahFilter` | `CrybabyGCB95` `VoxV847` `ColorsoundWow` | - |
...and more to come!
## Adding your own filter
You can also implement your own filter, by using the macro `def_rtf!`. See how i did it with the other filters for an example on how to use the macro.