Extending Aura with Csound Opcodes

Languages for music audio processing typically offer a large assortment of unit generators. There is great duplication among different language implementations, as each language must implement many of the same (or nearly the same) unit generators. Csound has a large library of unit generators and could be a useful source of reusable unit generators for other languages or for direct use in applications. In this study, we consider how Csound unit generators can be exposed to direct access by other audio processing languages. Using Aura as an example, we modified Csound to allow efficient, dynamic allocation of individual unit generators without using the Csound compiler or writing Csound instruments. We then extended Aura using automatic code generation so that Csound unit generators can be accessed in the normal way from within Aura. In this scheme, Csound details are completely hidden from Aura users. We suggest that these techniques might eliminate most of the effort of building unit generator libraries and could help with the implementation of embedded audio systems where unit generators are needed but a full embedded Csound engine is not required.