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 ext folder.
Some extensions are still in the progress of being designed and they are in the draft folder.
An extension comes with:
- an 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 methods 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
- 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
Plugins
- u-he, synthesizers and effects
- Surge, open source synthesizer and effect
- CLAP is enabled in nightly builds
Hosts
- Bitwig, you need at least Bitwig Studio 4.3 Beta 5
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