• Learn about CLAP
  • Entry point
  • Extensions
  • Fundamental extensions
  • Support extensions
  • Extra extensions
• Resources
  • Examples
  • Community related projects
  • Programming Language Bindings
  • Artwork

Learn about CLAP

CLAP stands for CLever Audio Plugin. It is an audio plugin ABI which defines a standard for Digital Audio Workstations and audio plugins (synthesizers, audio effects, ...) to work together.

To work with CLAP, include clap/clap.h.

The two most important objects are clap_host and clap_plugin.

src/plugin-template.c is a very minimal example which demonstrates how to wire a CLAP plugin.

Entry point

The entry point is declared in entry.h.

Extensions

Most features comes from extensions, which are in fact C interfaces.

// host extension
const clap_host_log *log = host->extension(host, CLAP_EXT_LOG);
if (log)
   log->log(host, CLAP_LOG_INFO, "Hello World! ;^)");

// plugin extension
const clap_plugin_params *params = plugin->extension(plugin, CLAP_EXT_PARAMS);
if (params)
{
   uint32_t paramsCount = params->count(plugin);
   // ...
}

The extensions are defined in the ext folder.

Some extensions are still in the progress of being designed and they are in the draft folder.

An extension comes with:

• a header #include <clap/ext/xxx.h>
• an extension identifier: #define CLAP_EXT_XXX "clap/XXX"
• host interfaces are named like: struct clap_host_xxx
• plugin interfaces are named like: struct clap_plugin_xxx
• each method must have a clear thread specification

You can create your own extensions and share them. Make sure that the extension identifier:

• includes versioning in case the ABI breaks
• is a unique identifier

All strings are valid UTF-8.

Fundamental extensions

This is a list of the extensions that you most likely want to implement and use to get a basic plugin experience:

• log, lets the host aggregate plugin logs
• thread-check, check which thread you are currently on, useful for correctness validation
• audio-ports, define the audio ports
• note-ports, define the note ports
• params, parameters management
• latency, report the plugin latency
• render, renders realtime or offline
• tail, processing tail length
• state, save and load the plugin state
• gui, generic gui controller

Support extensions

• thread-pool, use the host thread pool
• timer-support, lets the plugin register timer handlers
• posix-fd-support, lets the plugin register I/O handlers

Extra extensions

• note-name, give a name to notes, useful for drum machines
• tuning, host provided microtuning
• track-info
• quick-controls, bank of controls that can be mapped on a controlles with 8 knobs
• file-reference, let the host know about the plugin's file reference, and perform "Collect & Save"
• check-for-update, check if there is a new version of a plugin
• audio-ports-config, simple list of possible configurations
• surround, inspect surround channel mapping
• ambisonic, inspect ambisonic channel mapping

Resources

• clap-validator, a validator and automatic test suite for CLAP plugins.
• clapdb, a list of plugins and DAWs which supports CLAP

Examples

• clap-host, very simple host
• clap-plugins, very simple plugins
• schwaaa's plugin, basic example for prototyping CLAP audio plugins using Dear ImGui as the user interface

Community related projects

• clap-juce-extension, juce add-on
• MIP2, host and plugins
• Avendish, a reflection-based API for media plug-ins in C++ which supports Clap
• NIH-plug, an API-agnostic, Rust-based plugin framework aiming to reduce boilerplate without getting in your way

Programming Language Bindings

• clap-sys, rust binding
• CLAP-for-Delphi, Delphi binding

Artwork

• CLAP Logo Pack.zip