And Other Resources
2023-08-08
This morning, I’m giving a talk on The Audio Programmer YouTube channel. I’m going to speak about my Template Plugin for JUCE, and one of the things I want to emphasize is that there is no one right way to make a plugin. My template (which I’ve regrettably named The Template Plugin) is just where I personally landed through my own work. And, as I continue to do plugin work, I’m sure my template will change. I’ve gathered my list of additional plugin resources as a blog post to supplement the talk.
There are a number of existing open source plugin projects and templates. This is not a complete list by any means, but the following have been useful to me as references.
The Template Plugin is directly modified from the JUCE framework CMake
Audio Plugin Example, included in the JUCE library. The CMake Audio
Plugin Example provides a minimal framework for exporting audio plugins
from JUCE with CMake. It comes with an
AudioPluginAudioProcessor class for handling interactions
with the audio thread and an
AudioPluginAudioProcessorEditor class for handling
interactions with the message thread. The CMake Audio Plugin Example is
minimal and unopinionated; it does not provide any system for parameter
management, leaving the developer to create their own real-time safe
state management system.
Pamplejuce is an open source JUCE Template that supports, along with CMake, a testing system with the Catch2 framework, C++20, and a GitHub Actions configuration for building cross platform, testing, and code-signing. Pamplejuce is developed by Sudara Williams and is licensed under the MIT license. Pamplejuce builds on the JUCE CMake Audio Plugin Example by adding features necessary for distributing professional plugins. Compared to The Template Plugin, pamplejuce has a less opinionated approach for state management, using essentially the same source code as the JUCE CMake Audio Plugin Example with a more sophisticated build system.
Nicholas Berriochoa’s juce-template is an open source audio
plugin template which is most similar in scope to my Template Plugin. In
particular, Nicholas Berriochoa’s implementation includes logic for a
state management system that wraps plugin parameters and internal plugin
settings, as well as other useful features that go beyond The Template
Plugin such as react-js user interfaces, Rust-based digital signal
processing, testing, and key verification. While Nicholas Berriochoa
does use the AudioProcessorValueTreeState::SliderAttachment
class and listener systems, which I prefer to avoid for real-time safety
reasons, the juce-template project is still an incredible
resource for developers.
Surge XT is an award winning open source software synthesizer built in C++ with a JUCE-based user interface. Surge XT is released under the GNU GPLv3 license, and is a powerful reference for the digital signal processing and design patterns that go into a commercial-quality product. Surge XT supports a number of build platforms including MacOS, Windows, Linux, and Raspberry Pi. Furthermore, Surge XT can be built in the new CLAP plugin format.
valentine is an open source compressor plugin developed by
Jose Diaz Rohena. It is a great example of a simple plugin built using
the JUCE framework. While valentine incorporates some design
patterns that I prefer to avoid, such as using the
AudioProcessorValueTreeState::SliderAttachment class, it is
still an extremely valuable reference project. valentine is
released under the GNU GPLv3 license.
Vital is a popular “spectral warping wavetable synthesizer” by Matt Tytel released under GNU GPLv3. Vital is a massive project built on JUCE but with mostly custom code in C++. Furthermore, Vital uses hardware accelerated graphics for performant and detailed visualization in the UI. Vital is a great resource for understanding how a large plugin project can be organized.
Developing my own system for writing audio plugins has relied heavily on numerous plugin development tutorials and resources.
JUCE provides a series of beginner friendly tutorials for getting started with plugin development using the JUCE library. Unfortunately, some of these tutorials do not strictly adhere to the principals of real-time safe audio programming. Despite this, they are useful for developing an understanding of the JUCE framework. Furthermore, the JUCE forum contains a plethora of valuable questions and conversations between developers.
Joshua Hodge, better known as The Audio Programmer, has fostered a large community of audio developers around his YouTube and Discord channels. The Audio Programmer YouTube channel contains recordings of in-depth coding sessions and valuable interviews with developers. Furthermore, The Audio Programmer Discord community is one of the best places to search for plugin development questions, as many topics have been addressed in the Discord that are not posted on online forums.
The Audio Developers Conference is an annual professional developers conference hosted by JUCE. Recordings of talks from the Audio Developers Conference are posted online at the JUCE Youtube channel – these talks are an essential resource for understanding some of the more subtle aspects of audio programming, such as real-time safe programming, distribution, testing, and new approaches.
Timur Doumler’s talk on thread synchronization in real-time audio processing and Fabian Renn-Giles and Dave Rowland’s talk Real-Time 101 have been essential to my understanding of real-time programming and the development of this project. Timur Doumler has also released an open source library of low-latency real-time programming in C++, Crill, which implements some of the more sophisticated thread synchronization algorithms that I discuss in this paper. For another great reference on real-time safe audio programming, see Ross Bencina’s blog post Real-Time Audio Programming 101: Time Waits for Nothing.
Sudara Williams’ blog provides a number of detailed tutorials on optimizing, profiling, and testing audio plugins. This blog has informed my understanding of the JUCE repainting system and the best ways to profile plugin projects.
The second edition of The Computer Music Tutorial by Curtis Roads is a comprehensive and essential reference for all aspects of computer music. Furthermore, Julius O. Smith has a number of books and tutorials that are freely available online about physical modeling, digital filters, and other digital signal processing topics. The comprehensive DAFX book is another useful reference for implementing digital audio effects.
Finally, Oli Larkin’s More Awesome Music DSP, Jared Drayton’s Audio Plugin Development Resources, and Sudara William’s Awesome Juce are comprehensive lists of resources for audio programmers, which go well beyond the scope of this post and include a number of additional references.