Tracktion announced that their Tracktion Engine is Open Source from now. The aim of Tracktion Engine is to provide a high level data model and set of classes for building sequence based audio applications. You can build anything from a simple file-player or sequencer to a full blown DAW.
Over the past 3 years we’ve been refactoring our DAW engine to make it more modular, composable, customizable and simpler to use for a wide range of audio applications. Our aim is to take care of all the difficult and time consuming aspects of developing audio apps so you can focus on building great features and user interfaces people will love.
Tracktion Engine defines a high level document object model for time based, sequenced audio applications and provides an API to create, modify and play these back. Create an Engine object, our arrangement object, called an Edit, add some elements to it such as audio files, MIDI and plugins, then play it back or render it to an audio file.
Tracktion Engine is provided in JUCE module format making it incredibly quick and easy to setup and start creating projects. We’ve included a bunch of examples and accompanying tutorials along with scripts to build them so you can get up and running with the minimum of fuss.
More info here: Tracktion Engine