backtail / embedded-audio-tools

Embedded Toolbox for creating audio effects and synths

Embedded Audio Tools

Toolbox for creating audio effects with focus on the embedded aspect of things.

Memory

MemorySlice implements the Send trait since it only works safely on statically allocated memory.

Example

use embedded_audio_tools::memory_access::*;

// Thread-safe mutable slice
let mut buffer = [0.0_f32; 24];
let mut mut_slice = from_slice_mut(&mut buffer[..]);

// Null pointer and length of 0
let mut ptr_buffer = null_mut();

// Change associated buffer in runtime
unsafe { 
    ptr_buffer.change_mut_slice_unchecked(buffer.as_mut_ptr(), buffer.len());
}

assert_eq!(ptr_buffer.as_slice(), mut_slice.as_slice());

Biquad

Little suite of filters in a Biquad topology.

FilterType	Butterworth	Chebyshev	Bessel
Lowpass	- [x]	- [ ]	- [ ]
Highpass	- [x]	- [ ]	- [ ]
Allpass	- [x]	- [ ]	- [ ]
Notch	- [x]	- [ ]	- [ ]
Bell	- [x]	- [ ]	- [ ]
Lowshelf	- [x]	- [ ]	- [ ]
Highshelf	- [ ]	- [ ]	- [ ]

Example

use embedded_audio_tools::filter::{Biquad, BiquadCoeffs, Butterworth};

let mut biquad: Biquad<Butterworth> = Biquad::new(BiquadCoeffs::new());

// update coeffs for a lowpass
biquad.coeffs.lowpass(1000.0, 1.0, 48_000.0); // Cutoff = 1kHz, Q = 1.0, fs = 48kHz

// during audio callback
biquad.process(1.0); // process a sample

Delay Line

Uses the MemorySlice as an underlying building block for buffer handling. Can optionally interpolate in between samples either with lerp or lagrange.

Derivates

• Comb
• Allpass

Floats

Some common float related stuff:

• Bitreduction/manipulation
• Raw IEEE 754 conversion
• Various Interpolation Algorithms
• Additional embedded targeted math
• Decibel to voltage (and back) conversion

Envelope Generator

Currently only implements an ADSR with varying steepness.

Oscillator

A very bad audio oscillator (with no anti-aliasing whatsoever), but maybe not a bad LFO. Comes with the common waveforms:

• Sine
• Square
• Triangle
• Sawtooth

It is based on a software phase accumulator which is implemented as a trait bound. In theory, one could implement a hardware accumulator (i.e. timer).

Stereo

Panning, balacing and crossfading