Open Synth Descriptors
The MIDI standards say how messages travel; they say little about a given synth, and nothing about the sounds and firmwares people share. Open Synth Descriptors (OSD) describe the rest, in plain JSON checked by JSON Schema, free for any tool to read and write (CC0, public domain).
| Descriptor | What it says |
|---|---|
| Device | How it is recognised, its controls (CC, NRPN, RPN, SysEx), its messages and checksums, programs and banks, drum notes, and where each piece of data comes from |
| Maker profile | What a maker's devices share, extended by each |
| Sound | A shared sound, kit, pattern or clip: its data, device, firmware, author, licence and origin |
| Fingerprint | What was seen of a device plugged in (port names, its answer, the controls its knobs sent) and the model the person confirmed: recognises devices that do not say who they are |
| Firmware | A firmware or mod: author, repository, licence, what it changes to the MIDI, how to install and revert it |
Every one of the 978 devices of the catalogue is a valid OSD device descriptor: each device page links to its file. Each shared sound downloads as an OSD sound descriptor, and Which device is this? recognises a device by its fingerprint.
The format, examples, a checker and how to propose changes: github.com/roomi-fields/open-synth-descriptors. Version 0.2 is a draft (0.1 stays at osd/0.1/); a published version never changes, later ones live beside it.