OSSIA Score 3

The ossia system has been introduced in 2015 as a notation for interactive scores. We present the result of seven years of usage and improvements to the ossia score software which acts as both an editor and player for such scores, and how it morphed from a simple OSC-only control sequencer to a fully-fledged multimedia system supporting live audio and video processing, live-coding with multiple embedded programming languages, communication with a variety of software and hardware and adaptations for more traditional music creation such as support for varying tempo and time signatures. In particular, we mention a few "original sins" and implementation mistakes done at the beginning of the software engineering process and how they had to be fixed.