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1. Introduction

LADSPA is the Linux Audio Developers' Simple Plugin Architecture.

This document describes how to write LADSPA plugins and how to write hosts, which are programs that use LADSPA plugins,

This documentation is currently extremely incomplete.

Please be aware that the ladspa.h file is the official, definitive guide to the standard.

1.1 Terminology

There are several common bits of terminology:

plugin library

A shared library that can be loaded and unloaded "on-the-fly". Under linux we open plugins using the dlopen function.


a single sound-producing/consuming type identified with a descriptor whose C-type is LADSPA_Descriptor. A plugin library may contain several plugin descriptors, each with an index within plugin library. The indices must be consecutive and start with 0.

plugin instance

is a single running unit generator. There is a standard way to make plugin instances from plugins. In the host, we identify the instance by a handle whose type is void*.


The program which will load the plugins.

The standard describes the binary interface for a plugin library to present its plugins to the host.

1.2 The Plugin Lifecycle

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