What Is ossia score and What Can You Do With It?

ossia score is a free, open-source, cross-platform intermedia sequencer for scripting interactive scenarios with precise timing and flexible control. It fits projects where media playback, external device control, and conditional logic need to live on the same timeline — interactive performances, new media art installations, and any setup that must react to sensors, hardware controllers, or network messages. If you only need to arrange fixed audio tracks, a conventional DAW is simpler; ossia score becomes useful when the score itself has to branch, react, and talk to the outside world.

What "intermedia sequencer" means here

A traditional sequencer orders one kind of material — usually MIDI or audio. ossia score sequences several kinds of media together on an intelligent timeline, which is what "intermedia" refers to. According to the project, you can:

• Play back most audio formats, with multichannel support
• Play H.264 and HAP video through a cross-platform video and shader pipeline
• Send and receive OSC, MIDI, and DMX
• Communicate directly over HTTP or a serial port
• Control IoT systems via CoAP, MQTT, and BLE

So a single score can drive a video projection, trigger a synth, move stage lights over DMX, and read a sensor — all synchronized on one timeline.

Built for interactive shows, not just playback

The distinguishing feature is that the score can respond to the world. ossia score lets you:

• Trigger any part of the score from external conditions or hardware controls
• Use conditions to create branching scores visually — the timeline can take different paths depending on input
• Control and be controlled by external devices and protocols through a streamlined interface

This is what makes it a fit for interactive scenarios rather than linear playback: the same score can behave differently on each run depending on what the performer, sensor, or network sends.

Timeline and modular views in one tool

ossia score mixes two workflows that are usually separate:

You can switch between them at any point. The project also notes you can create state-machine-like scores for atemporal scenarios and nest and group without depth limit, so complex structures stay manageable.

Extending and scripting it

ossia score is designed to be programmed, not just clicked:

• JavaScript is embedded for livecoding directly in the score, for advanced mappings or device mapping scripts
• Faust is supported for building fast audio processors
• The C++ API lets you extend any part of the software
• Simple math expressions handle quick control tasks

Protocols and compatible environments

These protocols are implemented behind a common interface in libossia, so any app using libossia can bridge them:

OSC, Spout, Syphon, DMX, HTTP, Phidgets, Gamepad, Wiimote, Avid C|24, MQTT (including MQTTv5), CoAP, and BLE (Bluetooth Low Energy).

For creative coding, ossia score lists compatibility with Madmapper, Millumin, Max, Pure Data, openFrameworks, Processing, and glslViewer. You can connect to these either through traditional OSC, the more advanced OSCQuery protocol, or by directly integrating libossia.

When to choose ossia score

Choose it when your project needs conditional, branching, or externally triggered behavior across mixed media and hardware. Skip it when you need straightforward multitrack audio recording or a fixed linear edit — those tasks are better served by a standard DAW or video editor. The project describes itself as free and open-source; for current download and platform details, check ossia.io directly.