osccontrol-light - An audio plugin that speaks OSC

This software enables sending of Open Sound Control (OSC) messages from audio plugin host environments such as digital audio workstations (DAW).

Controls are tied to OSC messages directly in the host environment without encoding the control data as MIDI CC messages. This way, control automation can be sent and received via OSC at full resolution, and all time sequencing, automation recording, modulation and side-chaining functionality of the host environment can be used for external OSC control.

We provide an interactive GUI version, as a plugin as well as a standalone application, that enables prototyping of control presets by quick switching and reloading of preset definitions.
To integrate a preset into a host environment with automatable controls, the non-GUI version of the plugin can be pre-built to load a specific preset definition at runtime.

Control presets are defined in a YAML-based textual markup format.

Usage

To run the standalone GUI application, execute the osccontrol-light application binary. To run the GUI version of the plugin inside a host environment, load the osccontrol-light plugin.

The GUI elements are illustrated in the following.

To create a non-GUI instance of the plugin that provides automatable controls inside an audio plugin host environment, the plugin needs to be pre-built to load a certain preset file at runtime. See the build instructions below for details.

In headless mode, controls are exposed directly in the host UI and can be mapped to controller input or automated and modulated at full resolution. The following images show an example preset integrated into different host environments.

Environment variables:

• OSCCONTROL_SCALE_FACTOR: Set UI scale factor for high DPI displays.
• OSCCONTROL_PRESET_PATH: Set directory with preset definitions.

The directory specified via the GUI or OSCCONTROL_PRESET_PATH will be searched recursively for *.yaml preset definition files.

Please note: setting OSCCONTROL_PRESET_PATH in the environment is mandatory for non-GUI mode!

Preset Definitions

Control presets are defined in a YAML-based configuration format as follows. Refer to the Presets folder for more examples.

network:
  host: 127.0.0.1
  port: 6789

controls:
  - name: frequency
    type: float
    default: 440
    range: [100, 2000]
    message: /synth/freq

  - name: amplitude
    type: float
    default: 0.8
    message: /synth/amplitude

  - name: vibrato
    type: float
    default: 0.0
    message: /synth/vibrato

  - name: voices
    type: int
    default: 1
    range: [1, 6]
    message: /synth/voices

  - name: sub-oscillator
    type: toggle
    default: off
    message: /synth/sub-osc

Continuous float, discrete int, and boolean toggle control types are currently supported.

Platform Support

Different plugin SDKs are supported via the JUCE library (VST, VST3, AU, RTAS and AAX), as well as all major operating systems (GNU/Linux, MacOS and Microsoft Windows). The build is currently preconfigured to build VST3 plugins on all platforms, but this can be customized by adapting the CMakeLists.txt file accordingly.

Compilation

The plugin is built using the CMake build system. JUCE therefore needs to be properly deployed using CMake, using the Projucer is not supported.

First, download a copy of JUCE, or clone the github repository, and install it to a desired location.

git clone https://github.com/juce-framework/JUCE.git
mkdir JUCE/build
cd JUCE/build
cmake ..
cmake --install . --prefix <juce_install_root>

yaml-cpp is required as an additional dependency. Install it via your distribution or manually by following the instructions on the project page.

If either JUCE or yaml-cpp is installed in a non-standard location, remember to set CMAKE_PREFIX_PATH or *_DIR or similar, such that CMake is able to pick up the installation location.

We provide a script to build different versions of this plugin, which are preconfigured to load custom YAML presets at runtime. The interactive GUI version is always built, as a VST plugin as well as a standalone application. To build the GUI version (plugin and standalone), and plugins for the simple-synth and track-1 presets, just call the build script as follows.

./build_plugins.sh simple-synth track-1

Afterwards, you can find the prebuilt plugins for each preset as well as the GUI version in the Plugins directory in the top-level source tree.

You can perform a parallel build by passing the -j option with the desired number of threads.
To see all available options, call the build script with the -h option.

Please note: the build script is only supplied for your convenience. You can always build the plugin manually by calling CMake directly. To create build targets for specific presets, you can pass the PRESET_NAMES variable with a semicolon-separated list of preset names. For example:

mkdir build
cd build
cmake -DPRESET_NAMES="simple-synth;track-1" ..
cmake --build .

Licensing

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

See the LICENSE file for more details.