ARA Audio Random Access: Software Development Kit Installer

About ARA and the ARA SDK

ARA Audio Random Access is an extension for established plug-in standard APIs such as VST3 and Audio Units to allow for a much-improved DAW integration of plug-ins like Celemony's Melodyne which are conceptually closer to a sample editor than to a conventional realtime audio processor. It enables plug-ins to read audio samples from the DAW host at will, allowing them to implement more sophisticated processing algorithms not possible when being tied to individual realtime buffers. ARA further defines bi-directional exchange of audio content information such as tempo, keys and scales between plug-in and host, upon which both host and plug-ins can build numerous advanced editing features.

This Software Development Kit allows digital audio workstation (DAW) plug-in and host developers to implement and utilize ARA enabled plug-ins. It is copyright (c) 2012-2024, Celemony Software GmbH, and published under the Apache License, Version 2.0.

Any public release of ARA-enabled software should be based on a tagged public release of the ARA API. If temporarily using HEAD to study current work-in-progress, keep in mind that in order to achieve a concise long-term change history, any changes since the last tagged release may eventually be rebased.

ARA SDK Submodules

The ARA SDK consists of three components which are distributed as individual Git submodules so that dependent projects can pick only those parts of the SDK that are needed in their context. After cloning this top level module, you need to fetch these submodules, e.g. by running:

git submodule update --init --recursive

ARA API

The ARA_API module contains the core headers that define the actual ARA C API. ARAInterface.h is the main header, accompanied by a set of auxiliary headers for integrating ARA with each of the supported Companion APIs like VST3 or Audio Units. Additionally, ARA Audio File Chunks are defined in ARAAudioFileChunks.h. It includes extensive printer-friendly documentation.

ARA Library

The ARA_Library module wraps the low-level ARA C API with extensive C++11 classes and provides additional utility code that aides developers when implementing ARA-enabled products. It includes extensive browser-friendly documentation.

ARA Examples

The ARA_Examples module contains various sample code demonstrating how to both implement and host ARA enabled plug-ins. For details on building and running the examples, see their accompanying README. Note that some of the examples rely on external dependencies, see separate 3rd party README.

Companion APIs

Building ARA-enabled products relies on using at least one of the various established plug-in standard APIs as "Companion API" to ARA. Note that each of the Companion APIs comes with its own specific licensing conditions, as detailed in each SDK - some of these terms differ substantially from ARA's licensing conditions. The Companion APIs are therefore not installed automatically. However where applicable, optional install scripts for these SDKs are provided as convenience. Per default, these scripts will place the SDKs inside the ARA SDK folder, but this can be overridden by specifying alternate locations for each SDK, e.g. for VST3 by adding the argument:

-D ARA_VST3_SDK_DIR:PATH="your/path/to/vst3sdk"

VST3 SDK

You can set the variable ARA_VST3_SDK_DIR to an already existing local copy of the Steinberg VST3 SDK when generating the ARA example projects. Alternatively, a subset of the VST3 SDK sufficient for building the ARA examples can be fetched from GitHub via:

cmake -P install_vst3sdk.cmake

Audio Unit SDK

Similar to VST3, you can set ARA_AUDIO_UNIT_SDK_DIR to use an existing local copy of Apple's Audio Unit SDK (former Core Audio Utility Classes). They can also be downloaded directly from the Apple github page:

cmake -P install_AudioUnitSDK.cmake

AAX SDK

To use AAX, set the variable ARA_AAX_SDK_DIR to your local copy of the AAX SDK when generating the ARA example projects. The AAX SDK is not publicly available so there is no install script for it. Instead, it must be manually downloaded from Avid after registering with them.

Optional JUCE ARA Example

In order to provide an example with extensive UI, Celemony has created an experimental fork of the JUCE framework which contains an extended ARA demo plug-in that allows for studying ARA GUI integration both for host and plug-in developers.

Note that like some of the Companion APIs, JUCE imposes very different licensing conditions than the ARA SDK itself, see its included documentation.

To download this optional module run:

cmake -P install_JUCE_ARA.cmake

Now build and launch the Projucer found in extras/Projucer/Builds, choose Open Example > Plugins > ARAPluginDemo and export the project for your IDE of choice.