1. Microsoft’s Platform SDK
2. See More Results
3. VST Plug-Ins: What They Are And How To Use Them
4. Vst Plugin Folder
5. How To Design A Vst Plugins
6. New Free Vst Plugins

VST stands for Virtual Studio Technology. There are three types of VST plug-ins:

• VST instruments: These plug-ins generate audio and are either virtual synthesizers or samplers. Many VST instruments emulate the appearance and sound of famous hardware synthesizers. Popular VSP instruments include Massive, FM8, Absynth, Sylenth 1, Reaktor, Gladiator, Vanguard, and Omnisphere.
• VST effects: Effects process audio instead of generating it. VST effects function like hardware audio processors, like reverbs and phasers.
• VST MIDI effects:MIDI plug-ins process MIDI messages and send MIDI data to other VST instruments and hardware.

SynthEdit is the only save-as designer with C plug-in modules. These are extra functions you can download and add on later. Unlike restrictive built-in code features, or tedious low-level building blocks. This beautifully designed VST instrument plugin gives you endless sonic possibilities to create, explore and experiment with the sampled sounds of real musicians. The sampled instruments include various woodwind instruments, brass instruments, keys, complete string sections and a huge variety of orchestral percussion sounds.

VST Plug-ins

VST plug-ins can be used within a digital audio workstation, in programs like Pro Tools and Logic. They’re frequently used to emulate hardware outboard gear such as compressors, expanders, equalizers, and maximizers. You'll frequently find these distributed to emulate certain models of hardware; there's some for vintage compressors, and you'll frequently find effects that emulate vintage hardware (both in instrumental and stompbox-like effects).

Think of VST plug-ins as really affordable ways to make your home studio sound like a really expensive commercial operation.

VSTi Plug-ins

Aside from VST plug-ins, you'll also find VST-instrument or VSTi plug-ins. These can emulate really cool, but expensive, hardware (like Hammond B3 and Nord Electro). The quality of these VSTi plug-ins can vary from acceptable to really poor; it all depends on the quality of your system resources (RAM and scratch space on your hard drive, for example), and how well-sampled the instrument is. You also want to make sure that your VSTi plug-in offers true polyphonic content, meaning you can make life-like chords that don’t sound too artificial.

Quality

There are thousands of plug-ins available. Some only take a few hours to produce and are free, but the quality is terrible. Some are made by huge companies and sound amazing, but are expensive. VST plug-in developers try to recreate the sound as closely as possible, but the original instrument is probably always going to sound better than the plug-in. You might be trying to get the rich, full-bodied sound of an organ, for example, but who owns an organ? No one has access to every type of instrument, so a plug-in will have to do. The good news is that VST plug-in technology is improving, so quality can only get better with time.

VST Plug-in Standard

Created by Steinberg, a German musical software and equipment company, the VST plug-in standard is the audio plug-in standard that allows third-party developers to make VST plug-ins. Users can download VST plug-ins on Mac OS X, Windows, and Linux. The vast majority of VST plug-ins are available on Windows. Apple’s Audio Units are standard on Mac OS X (it’s actually considered a competing technology), and Linux lacks commercial popularity, therefore few developers create VST plug-ins for the operating system.

Where to Find VST Plug-ins

There are thousands of VST plug-ins available, both commercially and as freeware. The Internet is flooded with free VST plug-ins. Home Music Production and Bedroom Producers Blog have robust lists of VST plug-in recommendations, and Splice and Plugin Boutique also offer a ton of free plug-ins.

Introduction

Writing VST plugins is a lot of fun, but it’s even more fun to write your own host which uses the wide variety of plugins already out there to do something original and new. Making your own VST host is not a trivial task, but the trickiest part is figuring out how to load the plugins and connect them to your code’s callback functions. As the VST documentation is a bit sparse on the subject of hosting, this guide will assist you in setting up your own host.

This guide only covers loading the plugin and basic communication, and the language of choice here is C++. C# programmers should consider using the VST.NET framework, and I’m not sure what frameworks exist for other languages.

Also, it’s worth noting that Teragon Audio has developed an open-source VST host, MrsWatson. Feel free to look at the code and fork it for your own project! If you find yourself using a substantial portion of the MrsWatson source in your own code, please let me know so I can add a link to your project from the MrsWatson page.

Code conventions

In the course of your development, you will probably require logging, error handling, etc. To simplify the code in this tutorial, I have simply written “return -1” or “return NULL” statements, but you should consider expanding this to log some info or handle the error.

Also, this tutorial is written for both Windows and Mac OSX developers. As such, there is a lot of platform-specific code, which you will probably need to box with #ifdef/#endif statements in the preprocessor.

Setting up your build environment

You’ll need to first download and install the following tools:

1. Steinberg’s VST SDK, which requires you to make a free Steinberg Developer account. This tutorial assumes you are working with the VST 2.4 SDK.
2. Microsoft’s Visual C++ 2010 Express, if you wish to support Windows.
3. Microsoft’s Platform SDK, again if you are developing on Windows.
4. Xcode 4.x, if you are developing on Mac OS X.

Project configuration

Aside from your project files, you need only to add the VST SDK headers into your project’s include path. This includes the following files, which are located under the vstsdk2.4/pluginterfaces/vst2.x directory:

Microsoft’s Platform SDK

• aeffect.h
• aeffectx.h
• vsfxstore.h

On both Windows and Mac OSX, you should probably configure your program to build as a 32-bit binary, simply because most VST plugins are not 64-bit compatible yet. On the Mac, this gets to be a bit hairy because Apple is working to deprecate Carbon, which is a 32-bit framework. If anyone out there has example code in C (not objective-C) to load a plugin from bundle without using Carbon, please let me know so I can update this article.

Loading the VST plugin

After your host performs its own internal initialization routines, it is time to load the VST plugin from source. This procedure varies a bit depending on the platform, but the algorithm is fundamentally the same: find the plugin, load the dynamic library into memory, acquire the plugin’s main address, and create a VST callback connection. These callbacks are defined function pointers which you should define in one of your project’s header files, and are as follows:

On Windows, VST plugins are simply dynamically linked libraries (DLL’s). The code for opening a DLL library in Windows is fairly simple:

On Mac OSX, VST plugins are also dynamic libraries, but they are packaged as bundles. Your host can open these bundles through the Carbon API. On Mac OS9, VST plugins were packaged as CFM files, which has long since been deprecated, and it is highly unlikely that any modern VST host should need to support this format.

The procedure for opening a plugin under OSX is a bit more complex, but the code should be fairly straightforward. Keep in mind that although a VST plugin can be loaded from any location on disk, they are usually stored in either /Library/Audio/Plug-Ins/VST or $HOME/Library/Audio/Plug-Ins/VST.

Anyways, to load the VST plugin on Mac OSX, that will look something like this:

You need to keep the bundle pointer around until the host is ready to unload the plugin. At this point, you call CFBundleUnloadExecutable and then CFRelease on the bundle’s reference.

Setting up plugin callbacks

At this point, you should now have successfully loaded the plugin into memory, and you can now establish the plugin dispatcher callbacks:

See More Results

Plugin initialization

At this point, the plugin should be ready to go, so you can initialize it through the dispatcher handle created in the previous step:

Suspending and resuming

Calling the plugin’s suspend and resume methods are a bit counter-intuitive, and are done like this:

Plugin capabilities

The VST protocol uses “canDo” strings to define plugin capabilities, the most common of which are defined in audioeffectx.cpp in the PlugCanDos namespace near the top of the file. To ask a plugin if it supports one of these capabilities, make the following dispatcher call:

Host capabilities

The plugin can also ask the host if it supports a given capability, which is done through the hostCallback() function defined above. The implementation of this file looks something like this:

VST Plug-Ins: What They Are And How To Use Them

The full list of opcodes is defined in aeffect.h (for the VST 1.x protocol) and aeffectx.h (for VST 2.x protocol). There are a lot of opcodes, and your application doesn’t need to support them all, but you will soon figure out which ones are the most important through trial and error. Depending on the nature of the opcall, you will either be required to return a given integer value, call a method in the plugin’s dispatcher, or fill the *ptr pointer with some type of data. The VST SDK header files have fairly good documentation specifying what you need to do depending on the opcode.

The MrsWatson source code also contains an example implementation of this function with the most common opcode cases.

Processing audio

In the VST SDK 2.4, processReplacing() became the new standard call. You may have to add in support to your host for the old style of process() plugins, though there aren’t so many plugins out there which still do this. To have the plugin process some audio:

In the above code, there is an inputs and outputs array which should be initialized by your application as soon you have calculated the desired channel count and buffer size. You should not allocate the inputs and outputs arrays in the processAudio() function, as doing so may severely impact performance. Hence, the call to initializeIO() should be made as soon as possible and before the first call to processAudio(). You should also take care to properly initialize the data in both the inputs and outputs array to zero, or else you can get static or other random noise in the processed signal.

Sending MIDI messages

Vst Plugin Folder

Processing MIDI events is very similar to processing audio:

The above events array should be allocated and properly initialized by the host to contain the MIDI events which the plugin will receive. The VstEvent structure is defined in aeffectx.h, and there you will also find the respective VstEvent types, all of which are deprecated except for kVstMidiType and kVstSysExType.

Note that the plugin must support the receiveVstMidiEvent canDo in order to process MIDI.

How To Design A Vst Plugins

Final Notes

New Free Vst Plugins

At this point, you should have a basic working host capable of loading and communicating with a VST plugin. As you continue your development, take care to thoroughly read the VST SDK header files and other associated documentation, as they will provide you with further hints as to the correct implementation. Also, you should take time to create good logging facilities in your host, particularly in the hostCallback() method, as most plugin incompatibilities are usually triggered from some error there.