DSSI is an audio plugin API for software instruments (soft synths) and effects. It is based on the LADSPA plugin API, the ALSA sequencer event types, and OSC (Open Sound Control) communications with custom GUIs.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.