ossia score is described as 'OSSIA Score is an interactive sequencer for intermedia authoring. It allows to create flexible and interactive scenarios and is especially designed for live performance, art installations, museography or any context requiring a precise and interactive execution of timed events' and is an app in the Audio & Music category. There are three alternatives to ossia score for Mac, Windows and Linux. The best alternative is VSXu Ultra Artiste, which is both free and Open Source. Other great apps like ossia score are Vezer (Paid) and IanniX (Free, Open Source).
VSXu Ultra Artiste lets you create stunning open GL based audio reactive visuals. Its unique modular interface gives you drag and drop functionality gives you access to dozens of modules that allow easy compositing of presets that can be played in VSXu player.
Vezér is a timeline and control software for audiovisual artists. It enables control and synchronization of any MIDI, OSC or DMX enabled environments - real-time video software, lighting rigs, etc. - through the use of timeline based automation.