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Audio plug-in support

Audio plugins

Plug-ins can simply be dropped from the process library), under the Audio section, into the main view.

If the plug-in has a custom UI, it is possible to make it show up with the small “window” icon on the plug-in header.

For plug-ins with many controls, controls won’t show up by default in the score user interface. When changed from the plug-in UI, if any, will show up in score and be automatable. The little “x” allows to remove an unwanted parameter.

Common formats: VST, VST3, LV2, JSFX

Common plug-in formats are supported:

  • VST 2.4 on all platforms.
  • VST 3 on all platforms.
  • LV2 on Linux. It is yet not shipped in the official releases, score needs to be built for source for LV2 support (or be used as a distribution package)
  • JSFX on all platforms.

Plug-ins are started automatically on startup. If for some reason this must be disabled, because the scanning process causes issues, one can set the SCORE_DISABLE_AUDIOPLUGINS=1 environment variable. Already scanned plug-ins will still be available for VST and VST3.

It is possible to save and reload presets ; however the built-in VST presets are not supported yet.

VST2 plug-ins can be rescanned from the preferences.

Controlling VST parameters

To be able to automate and connect VST parameters to other parts of the session, it is necessary to make them visible in the nodes. For plug-ins with less than a dozen parameters, they will always be shown by default. For plug-ins with more parameters, this is however opt-in.

VST inspector UI

The first button allows to show / hide the audio plug-in UI. The second, when enabled, means that the plug-in’s parameters will be checked for changes: whenever a value changes, it will appear in the score UI and be open to automation, etc.

Here is the complete procedure:

Controlling VST parameters

This is currently only implemented for VST2, other plug-in APIs have all their parameters shown until the feature is implemented there too.

Adding JSFX plug-ins

JSFX plug-ins can be added in the user library. Score will look for files ending with the .jsfx extension.

If you are on Unix or a system with bash, you can rename the JSFX plugins without extensions this way:

$ find . -type f ! -name '*.*' -exec perl-rename 's/$/.jsfx/' {} \;

Here are some links to free JSFX collections:

Some JSFX plug-ins need separate data files. To ensure that they can find it, the following organization is recommended:

jsfx_folder/Effects/foo/effect.jsfx
jsfx_folder/Data/<matching data files>

For instance, a complete path on a Mac with the default user library location would look like:

/Users/you/Documents/ossia/score/packages/jsfx/Effects/dynamics/general_dynamics.jsfx
/Users/you/Documents/ossia/score/packages/jsfx/Data/amp_models/SomeImpulse.wav

Advanced plug-in and extensions formats

It is also possible to use less common systems for audio processing:

Some of these plug-in systems, like Faust are source-based: that is, score will compile the source code of the plug-in directly, which can take a few seconds when dropping the plug-in in the session.

Preset support for these plug-ins is a work-in-progress.