rsynth

An API abstraction for API's for audio plugins and applications. Use it to write real-time audio effects, software synthesizers, ... and target different platforms (vst, jack, ...). It is currently most suitable for real-time or "streaming" audio processing. E.g. you cannot use it to reverse audio in time.

Feature matrix

We focus on API's that are typically used for audio effects and software synthesizers. If you want to "just" play audio on various platforms, cpal may be better suited for you.

Feature flags

Many features are behind feature flags:

• all: all the features below
  • backend-jack: create standalone jack applications.
  • backend-vst: create VST 2.4 plugins.
  • backend-combined-all: all the "combined" backends for offline processing and testing. This always include in-memory dummy and testing backends.
    • backend-combined-hound: read and write .wav files with the hound crate
    • backend-combined-wav-0-6: read and write .wav files with the wav crate
    • backend-combined-midly-0-5: read and write .mid files with the midly crate
  • rsor-0-1: add support for using the rsor crate for some methods (if you prefer rsor over vecstorage)

Documentation

The API documentation can be found

• on docs.rs for the version that is distributed via crates.io.
• on GitHub pages for the documentation of the master branch
• on your local machine after running cargo rustdoc --features all

Philosophy and design

rsynth presents itself as a library, rather than a framework. Rather than trying to solve every problem (which is not feasible for the small team), rsynth is designed to be easy to combine with other crates for specific tasks, such as

• polyphony: the name says it all
• wmidi: encode and decode midi messages in real-time
• midi-consts: constants for low-level handling of midi data
• rtrb, a realtime-safe single-producer single-consumer ring buffer that can be used to communicate between threads.

Background on the design can be found in the design.md document.

Examples

There are full examples in the examples folder in the source code.

Applications and plugins using rsynth

The following applications and plugins use rsynth:

• print_chords, a stand-alone jack application that listens to a midi port and prints the chord names.

Current State

rsynth is in its early stage of development, and many changes are breaking changes. The team behind it is very small, so progress is slow.

Roadmap

We try to focus on features that we are actually using ourselves. This helps to ensure that the features that we provide, can actually be used in practice. So if you want to use a particular feature that isn't there yet, feel free to open an issue (if needed), and you can volunteer to test the feature before it is merged.

In the long term, rsynth can be split into multiple crates for maximum re-usability and for license clarity (e.g. when one back-end requires a different license). We're currently keeping everything together because it's easier to coordinate breaking changes over the various components in this way.

Contributing

Contributions and suggestions are welcome! See CONTRIBUTING.md for more details.

License

The source code of rsynth is licensed under the MIT/BSD-3 License.

Note: we plan to switch to MIT/Apache 2.0 in a future release.

Note that in order to use rsynth in combination with other crates (libraries), the combined work needs to comply with the license of that crate as well. In particular, the following optional dependencies may require your attention:

• the hound crate (behind the backend-combined-hound feature) uses the Apache license, see its readme for more details
• the wav crate (behind the backend-combined-wav feature) uses the LGPL license