Crate synfx_dsp

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!

§Copyright, Licenses, Attribution, Contributions

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§

AllPass: An all-pass filter based on a delay line.
AtomicFloat: An atomic float that can be asynchronously read/written. Best combined with an Arc<...>.
AtomicFloatPair: The AtomicFloatPair can store two f32 numbers atomically.
Biquad: 2nd order IIR filter implemented in normalized Direct Form I.
BiquadCoefs
ChangeTrig: Signal change detector that emits a trigger when the input signal changed.
Comb
CtrlPitchQuantizer
CustomTrigger: Trigger signal detector with custom range.
DCBlockFilter
DCFilterX4: Basic 4 channel SIMD DC-filter from Understanding Digital Signal Processing by Richard Lyons.
DattorroReverb: Dattorro plate reverb implementation.
DelayBuffer: This is a delay buffer/line with linear and cubic interpolation.
EnvADSRParams
EnvRetrigAD: A retriggerable AD (Attack & Decay) envelope with modifyable shapes for the attack and decay.
EnvRetrigADSR
EnvState: Envelope state structure for the macros crate::env_hold_stage, crate::env_target_stage and crate::env_sustain_stage.
FixedOnePole
GateSignal: Gate signal generator for HexoDSP nodes.
OnePoleHPF
OnePoleLPF
Oversampling: Implements oversampling with a ratio of N and a 4 times cascade of Butterworth lowpass filters (~48dB?).
PolyBlepOscillator: This is a band-limited oscillator based on the PolyBlep technique.
PolyIIRHalfbandFilter: This is a polyphase iir halfband filter (cutoff at fs/4) consisting of cascades of allpasses. translated from the freely available source code at https://www.musicdsp.org/en/latest/Filters/39-polyphase-filters.html
Quantizer
RampValue: A ramped value changer, with a configurable time to reach the target value.
RandGen: Random number generator based on xoroshiro128. Requires two internal state variables. You may prefer SplitMix64 or Rng which only use one u64 as state.
Rng: Random number generator based on SplitMix64. Requires two internal state variables. You may prefer SplitMix64 or Rng.
SlewValue: A slew rate limiter, with a configurable time per 1.0 increase.
SplitMix64: A splitmix64 random number generator.
TriSawLFO: An LFO with a variable reverse point, which can go from reverse Saw, to Tri and to Saw, depending on the reverse point.
TrigSignal: Trigger signal generator for HexoDSP nodes.
Trigger: Trigger signal detector for HexoDSP.
TriggerPhaseClock: Generates a phase signal from a trigger/gate input signal.
TriggerSampleClock
VPSOscillator: Vector Phase Shaping Oscillator. The parameters d and v control the shape of the sinus wave. This leads to interesting modulation properties of those control values.

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§

DattorroReverbParams
Flt

Functions§

apply_distortion
coef2gain_db: Converts a coefficient/factor to decibels
crossfade: Linear crossfade.
crossfade_clip: Linear crossfade with clipping the v2 result.
crossfade_cpow: Constant power crossfade.
crossfade_drive_tanh: Linear (f32) crossfade with driving the v2 result through a tanh().
crossfade_exp: Exponential crossfade.
crossfade_log: Logarithmic crossfade.
cubic_interpolate: Hermite / Cubic interpolation of a buffer full of samples at the given index. len is the buffer length to consider and wrap the index into. And fract is the fractional part of the index.
f_distort: Signal distortion by Bram de Jong.
f_fold_distort: Foldback Signal distortion
fast_cos: A faster implementation of cosine. It’s not that much faster than Rust’s built in cosine function. But YMMV.
fast_sin: A faster implementation of sine. It’s not that much faster than Rust’s built in sine function. But YMMV.
gain_db2coef: Converts gain in decibels to a factor/coeffient
init_cos_tab: Initializes the cosine wave table for fast_cos and fast_sin.
init_white_noise_tab: Initializes [WHITE_NOISE_TAB]
lerp: Apply linear interpolation between the value a and b.
lerp64: Apply 64bit linear interpolation between the value a and b.
next_xoroshiro128: Given the mutable state generates the next pseudo random number.
note_to_freq: Converts a midi note (0 to 128) to a frequency
process_1pole_highpass: Process a very simple one pole 6dB high pass filter. Useful in various applications.
process_1pole_lowpass: Process a very simple one pole 6dB low pass filter. Useful in various applications, from usage in a synthesizer to damping stuff in a reverb/delay.
process_1pole_tpt_highpass: Process a very simple one pole 6dB high pass filter in TPT form. Useful in various applications.
process_1pole_tpt_lowpass: Process a very simple one pole 6dB low pass filter in TPT form. Useful in various applications, from usage in a synthesizer to damping stuff in a reverb/delay.
process_hal_chamberlin_svf: Process a HAL Chamberlin filter with two delays/state variables that is 12dB. The filter does internal oversampling with very simple decimation to rise the stability for cutoff frequency up to 16kHz.
process_simper_svf: This function processes a Simper SVF with 12dB. It’s a much newer algorithm for filtering and provides easy to calculate multiple outputs.
process_stilson_moog: This function implements a simple Stilson/Moog low pass filter with 24dB. It provides only a low pass output.
quick_tanh
quick_tanh64
quicker_tanh
quicker_tanh64
rand_01
rand_u64
sqrt4_to_pow4: A pow like shape function for exponential envelopes. It’s a bit faster than calling the pow function of Rust.
square_35
square_135
tanh_approx_drive
tanh_levien: Cheap 4 channel tanh to make the filter faster.
tanh_levien_f64: Another tanh approximation. See also tanh_levien.
u64_to_open01: Maps any u64 to a f64 in the open interval [0.0, 1.0).

Crate synfx_dspCopy item path