Crate synfx_dsp

source ·
Expand description

synfx-dsp DSP real time audio synthesis, effect algorithms and utilities for Rust

Most of the algorithms and implementations in this library have been implemented for HexoDSP and used in HexoSynth. I factored them out, because they seem useful in other contexts too, for instance the synfx-dsp-jit crate.

I collected most of the algorithms in this crate from various GPLv3 compatible sources. They also were partially translated from multiple different C++ projects. I tried to document the source and source license diligently in the comments of this crate. I apologize if any attribution is missing and would welcome patches or reports.

Feel free to use these algorithms and utilities. Help, patches and additions are appreciated if they comply with the GPL-3.0-or-later license and don’t break the test suite in HexoDSP.

Attention: HexoDSP comes with a large test suite that also covers these algorithms. And that is the one that also has to pass if these algorithms are touched. The flip side is, that these implementations are actually covered by a test suite.

Requires Nightly as of 2022-10-02 due to std::simd!

Here is a list of sources parts of this library copied or translated code from:

  • crate::quicker_tanh64 / crate::quicker_tanh
    quickerTanh / quickerTanh64 credits to mopo synthesis library:
Under GPLv3 or any later.
Little IO <littleioaudio@gmail.com>
Matt Tytel <matthewtytel@gmail.com>
  • crate::quick_tanh64 / crate::quick_tanh
    quickTanh / quickTanh64 credits to mopo synthesis library:
Under GPLv3 or any later.
Little IO <littleioaudio@gmail.com>
Matt Tytel <matthewtytel@gmail.com>
  • crate::tanh_approx_drive
    Taken from ValleyAudio
Copyright Dale Johnson
https://github.dev/ValleyAudio/ValleyRackFree/tree/v2.0
Under GPLv3 license
  • crate::AtomicFloat
    Implementation from vst-rs
https://github.com/RustAudio/vst-rs/blob/master/src/util/atomic_float.rs
Under MIT License
Copyright (c) 2015 Marko Mijalkovic
  • crate::Biquad
    The implementation of this Biquad Filter has been adapted from
SamiPerttu, Copyright (c) 2020, under the MIT License.
See also: https://github.com/SamiPerttu/fundsp/blob/master/src/filter.rs
  • crate::DattorroReverb
    This file contains a reverb implementation that is based
on Jon Dattorro's 1997 reverb algorithm. It's also largely
based on the C++ implementation from ValleyAudio / ValleyRackFree

ValleyRackFree Copyright (C) 2020, Valley Audio Soft, Dale Johnson
Adapted under the GPL-3.0-or-later License.

See also: https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Plateau/Dattorro.cpp
     and: https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Plateau/Dattorro.hpp

And: https://ccrma.stanford.edu/~dattorro/music.html
And: https://ccrma.stanford.edu/~dattorro/EffectDesignPart1.pdf
  • crate::process_1pole_lowpass / crate::process_1pole_highpass
    one pole lp from valley rack free:
https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/OnePoleFilters.cpp
  • crate::process_1pole_tpt_lowpass / crate::process_1pole_tpt_highpass
    one pole from:
http://www.willpirkle.com/Downloads/AN-4VirtualAnalogFilters.pdf
(page 5)
  • crate::FixedOnePole
    Fixed one pole with setable pole and gain.
Implementation taken from tubonitaub / alec-deason
from https://github.com/alec-deason/virtual_modular/blob/4025f1ef343c2eb9cd74eac07b5350c1e7ec9c09/src/simd_graph.rs#L4292
under MIT License
  • crate::process_hal_chamberlin_svf
    Hal Chamberlin's State Variable (12dB/oct) filter
https://www.earlevel.com/main/2003/03/02/the-digital-state-variable-filter/
Inspired by SynthV1 by Rui Nuno Capela, under the terms of
GPLv2 or any later:
  • crate::process_simper_svf
    Simper SVF implemented from
https://cytomic.com/files/dsp/SvfLinearTrapezoidalSin.pdf
Big thanks go to Andrew Simper @ Cytomic for developing and publishing
the paper.
  • crate::process_stilson_moog
    Stilson/Moog implementation partly translated from here:
https://github.com/ddiakopoulos/MoogLadders/blob/master/src/MusicDSPModel.h
without any copyright as found on musicdsp.org
(http://www.musicdsp.org/showone.php?id=24).

It's also found on MusicDSP and has probably no proper license anyways.
See also: https://github.com/ddiakopoulos/MoogLadders
and https://github.com/rncbc/synthv1/blob/master/src/synthv1_filter.h#L103
and https://github.com/ddiakopoulos/MoogLadders/blob/master/src/MusicDSPModel.h
  • crate::DCBlockFilter
    translated from Odin 2 Synthesizer Plugin
Copyright (C) 2020 TheWaveWarden
under GPLv3 or any later
  • crate::cubic_interpolate
    Hermite interpolation, take from
https://github.com/eric-wood/delay/blob/main/src/delay.rs#L52

Thanks go to Eric Wood!

For the interpolation code:
MIT License, Copyright (c) 2021 Eric Wood
  • crate::TriSawLFO
    Adapted from https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/LFO.hpp

ValleyRackFree Copyright (C) 2020, Valley Audio Soft, Dale Johnson
Adapted under the GPL-3.0-or-later License.
  • crate::PolyBlepOscillator
    PolyBLEP by Tale
(slightly modified)
http://www.kvraudio.com/forum/viewtopic.php?t=375517
from http://www.martin-finke.de/blog/articles/audio-plugins-018-polyblep-oscillator/
  • crate::VPSOscillator
    This oscillator is based on the work "VECTOR PHASESHAPING SYNTHESIS"
by: Jari Kleimola*, Victor Lazzarini†, Joseph Timoney†, Vesa Välimäki*
*Aalto University School of Electrical Engineering Espoo, Finland;
†National University of Ireland, Maynooth Ireland

See also this PDF: http://recherche.ircam.fr/pub/dafx11/Papers/55_e.pdf
  • crate::Oversampling
    Loosely adapted from https://github.com/VCVRack/Befaco/blob/v1/src/ChowDSP.hpp
Copyright (c) 2019-2020 Andrew Belt and Befaco contributors
Under GPLv-3.0-or-later

Which was originally taken from https://github.com/jatinchowdhury18/ChowDSP-VCV/blob/master/src/shared/AAFilter.hpp
Copyright (c) 2020 jatinchowdhury18
  • crate::next_xoroshiro128
    Taken from xoroshiro128 crate under MIT License
Implemented by Matthew Scharley (Copyright 2016)
https://github.com/mscharley/rust-xoroshiro128
  • crate::u64_to_open01
    Taken from rand::distributions
Licensed under the Apache License, Version 2.0
Copyright 2018 Developers of the Rand project.
  • crate::SplitMix64
    Copyright 2018 Developers of the Rand project.

Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
<LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
option. This file may not be copied, modified, or distributed
except according to those terms.
- splitmix64 (http://xoroshiro.di.unimi.it/splitmix64.c)
  • crate::f_distort / crate::f_fold_distort
    Ported from LMMS under GPLv2
* DspEffectLibrary.h - library with template-based inline-effects
* Copyright (c) 2006-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>

Original source seems to be musicdsp.org, Author: Bram de Jong
see also: https://www.musicdsp.org/en/latest/Effects/41-waveshaper.html
  • crate::PolyIIRHalfbandFilter
    Taken from va-filter by Fredemus aka Frederik Halkjær aka RocketPhysician
https://github.com/Fredemus/va-filter
Under License GPL-3.0-or-later

originally translated from the freely available source code
at https://www.musicdsp.org/en/latest/Filters/39-polyphase-filters.html
  • crate::DCFilterX4
    Basic 4 channel SIMD DC-filter from Understanding Digital Signal Processing by Richard Lyons.

Taken from va-filter by Fredemus aka Frederik Halkjær aka RocketPhysician
https://github.com/Fredemus/va-filter
Under License GPL-3.0-or-later
  • crate::fh_va::LadderFilter / crate::fh_va::Svf / crate::fh_va::SallenKey
    Taken from va-filter by Fredemus aka Frederik Halkjær aka RocketPhysician
https://github.com/Fredemus/va-filter
Under License GPL-3.0-or-later

Modules

  • fh_va
    This module contains the VA filter code of Fredemus’ aka Frederik Halkjær aka RocketPhysician.

Macros

  • assert_decimated_feq
    This macro allows you to float compare two vectors to a precision of 0.0001, only every $decimate element will be looked at though. Useful for keeping the fixed value tables in your DSP code small.
  • assert_decimated_slope_feq
    Calculates the (linear) slope between consequtive values in $vec and compares the slopes with $cmp_vec with a precision of 0.0001. This macro only looks at every $decimate slope.
  • assert_decimated_slope_feq_fine
    Calculates the (linear) slope between consequtive values in $vec and compares the slopes with $cmp_vec with a precision of 0.0000001. This macro only looks at every $decimate slope.
  • assert_decimated_slope_feq_sfine
    Calculates the (linear) slope between consequtive values in $vec and compares the slopes with $cmp_vec with a precision of 0.000000001. This macro only looks at every $decimate slope.
  • assert_slope_feq
    Calculates the (linear) slope between consequtive values in $vec and compares the slopes with $cmp_vec with a precision of 0.0001.
  • assert_vec_feq
    This macro allows you to float compare two vectors to a precision of 0.0001.
  • env_hold_stage
    Holds the previous state.current value for $time_ms.
  • env_sustain_stage
    Holds the previous state.current value until $gate drops below crate::TRIG_LOW_THRES.
  • env_target_stage
    Increases/Decreases state.current value until you are at $value within $time_ms.
  • env_target_stage_lin_time_adj
    Increases/Decreases state.current value until you are at $value within an adjusted $time_ms. Depending on how close state.start is to $value, $time_ms is linearily shortened. For this to work, you need to supply the supposed starting value of the envelope.
  • fa_distort
    Returns the name of the distortion selected by the dist_type parameter of the apply_distortion function.

Structs

Constants

  • TRIG_HIGH_THRES
    The threshold, once reached, will cause a trigger event and signals a logical ‘1’. Anything below this is a logical ‘0’.
  • TRIG_LOW_THRES
    The lower threshold for the schmidt trigger to reset.
  • TRIG_SIGNAL_LENGTH_MS
    ! Contains various utilities for trigger signals in a modular synthesizer.

Traits

Functions