Faust - Programming Language for Audio Applications and Plugins

Grame, Centre National de Creation Musicale: https://www.grame.fr

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Introduction

Faust (Functional Audio Stream) is a functional programming language specifically designed for real-time signal processing and synthesis. A distinctive characteristic of Faust is to be fully compiled.

The Faust compiler translates DSP specifications into very efficient code for various languages (C++, C, JAVA, LLVM IR, WebAssembly etc.) working at sample level. It targets high-performance signal processing applications, libraries and audio plug-ins for a variety of audio platforms and standards. A same Faust specification can be used to easily generate various kinds of native standalone applications, iOS and Android apps, as well as Csound, LADSPA, Max/MSP, PD, Q, SuperCollider, VST, AU plugins, etc. (see the README in the /architecture folder for an exhaustive list).

While there are Faust contributors everywhere across the globe, Faust is mainly being developed at Grame, Centre National de Creation Musicale (https://www.grame.fr), its birthplace.

Versions and Branches

The Faust distribution can be downloaded on the Faust Github repository: https://github.com/grame-cncm/faust. Official releases packages are also available here: https://github.com/grame-cncm/faust/releases.

In the following subsections, details about the branches of the repository are given.

master

master is the main Faust branch. It can compile in different languages: C, C++, JAVA, LLVM IR, WebAssembly etc. It also implements experimental features such as multi-rate capabilities, etc. Thanks to its ability to generate LLVM IR and by using LLVM JIT, Faust is "embeddable" in any C++ program through a library called libfaust. Compiling Faust relies on LLVM. Finally, Faust is needed by some sister projects of Faust such as FaustLive, FaucK, faustgen~, etc. This branch also contains the old Faust1 C++ backend.

master-dev (Preferred Development Branch)

master-dev is the development sub-branch of master. It is used by Faust developers to commit their changes and can be considered as "the main development branch." The goal is to make sure that master is always functional. Merges between master-dev and master are carried out multiple times a week by the GRAME team.

More experimental branches are also available but are not documented here.

Overview of the Faust Distribution

This is an overview of the content of the top-level folders of the Faust distribution. Most of these folders contain their own README describing their content in more details.

architecture/          : the architecture files currently supported
build/                 : build tools and scripts (cmake based)
benchmark/             : tools to measure the impact of various compiler options
compiler/              : sources of the Faust compiler
debian/                : files for Debian installation
documentation/         : Faust developer's documentation
examples/              : Faust programs examples organized by categories
installer/             : various installers for Linux distribution
libraries/             : DSP libraries
syntax-highlighting/   : support for syntax highlighting for several editors
tests/                 : various tests
tools/                 : additional easy-to-use scripts (faust2...) to produce binaries and plugins
windows/               : Windows related resources

Libraries

Faust libraries are now in a separated project and included as a git submodule. We also include oboe (https://github.com/google/oboe) as submodule in two different places: architecture/android/app/oboe and architecture/smartkeyboard/app/oboe. These submodules are synchronized from time to time in the main Faust repository using the following commands:

git submodule update --remote --merge
git add libraries architecture/android/app/oboe architecture/smartKeyboard/android/app/oboe
git commit -m "Faust updated to the latest version of the libraries and oboe."
git push

Compilation and Installation

Since release 2.5.18, Faust compilation and installation is based on CMake. For details about compilation, you should look at the Faust wiki pages or go directly to the simple tutorial to compile and install.

Using the Faust Examples

The /examples folder contains dozen of example Faust codes organized by categories. There are many options to use them.

Online Faust Editor

The Online Faust Editor is a zero-conf tool that provides all the compilation services, including binaries generation for all the supported platforms and architectures.

Online Faust IDE

The Online Faust IDE is a zero-conf tool that provides all the compilation services, including binaries generation for all the supported platforms and architectures, but also various utilities for signal processing development.

Faust Playground

Faust Playground is an online tool to compile and use Faust code directly in a web browser. To use a Faust example from the /examples folder, just drag-and-drop it in the work space and it should work right away!

FaustLive

FaustLive is a program that was designed to facilitate the prototyping of Faust codes. It embeds the LLVM on-the-fly compiler of Faust2 allowing you to very rapidly compile Faust codes on your computer. Binaries and installation packages of FaustLive are available for Linux, Windows and OSX.

faust2... Scripts and Programs

The faust2... scripts and programs are command line tools allowing to compile Faust codes to any of the supported Faust targets ("architectures"). They are placed on your system during the Faust installation process. The fastest way to get an exhaustive list of all of them is to open a terminal window, type faust2, and then press the Tab key for auto-completion. For example, to compile a Faust code as a JACK application with a Qt interface, run:

faust2jaqt yourCode.dsp

The most commonly used faust2 scripts are:

faust2alqt              : ALSA application with Qt UI
faust2ladspa            : LADSPA plug-in
faust2pdf               : pdf block diagram
faust2supercollider     : SuperCollider external
faust2alsa              : ALSA application with GTK UI
faust2faustvst          : VST plug-in
faust2lv2               : LV2 plug-in
faust2plot              : command line program to debug DSP (sample plotting, etc.)
faust2svg               : SVG block diagram
faust2alsaconsole       : ALSA command line program
faust2mathdoc           : automatic pdf mathematical documentation
faust2png               : png block diagram
faust2android           : Android app
faust2graph             : svg graph
faust2puredata          : PureData external
faust2api               : API generator
faust2msp               : MaxMSP 5 external and patch
faust2max6              : MaxMSP 6 (and later) external and patch
faust2ios               : iOS app
faust2ros               : ROS app
faust2au                : Audio Unit plugin
faust2rosgtk            : ROS app with GTK UI
faust2bela              : BELA program
faust2jack              : JACK application with GTK UI
faust2netjackconsole    : NetJack command line program
faust2rpialsaconsole    : Raspberry Pi ALSA command line program
faust2caqt              : CoreAudio application with Qt UI
faust2jackconsole       : JACK command line program
faust2netjackqt         : NetJack application with Qt UI
faust2rpinetjackconsole : Raspberry Pi JACK command line program
faust2caqtios           : iOS app with Qt UI
faust2octave            : Octave script
faust2csound            : CSOUND Opcode
faust2owl               : OWL Program
faust2sig               : SVG signal
faust2jaqt              : JACK application with Qt UI

Obviously, the corresponding dependencies for each of them must be installed on your system for compilation to be successful. For example, if you use faust2jaqt, JACK and Qt libraries must be installed.

Documentation and Resources

• /documentation/faust-quick-reference.pdf contains the most up-to-date documentation of Faust.
• /documentation/library.pdf contains the documentation of the Faust DSP libraries.
• The Faust website contains useful resources around Faust.
• The Faust online course or the Faust Hero in 2 Hours tutorial might be good starting points for beginners.
• Julius Smith's website is an incredible resource on various topics around DSP and Faust.

Acknowledgments

Many persons have been contributing to the Faust project by providing code for the compiler, architecture files, libraries, examples, documentation, scripts, bug reports, ideas, etc.

I would like to thank them and especially: Fons Adriaensen, Tiziano Bole, Baktery Chanka, Thomas Charbonnel, Damien Cramet, Etienne Gaudrin, Albert Graef, Stefan Kersten, Victor Lazzarini, Matthieu Leberre, Mathieu Leroi, Kjetil Matheussen, Remy Muller, Sampo Savolainen, Nicolas Scaringella, Stephen Sinclair, Travis Skare, Julius Smith, as well as my colleagues at GRAME, in particular : Dominique Fober, Stephane Letz and Karim Barkati, and from the ASTREE project : Jerome Barthelemy (IRCAM), Alain Bonardi (IRCAM), Raffaele Ciavarella (IRCAM), Pierre Jouvelot (Ecole des Mines/ParisTech), Laurent Pottier (U. Saint-Etienne)

Questions and suggestions

If you have questions suggestions and comments, or if you want to contribute to the project, two mailing lists are available:

• Development List
• Users List

Yann Orlarey