Fully functional support for the VST plugin standard is one of the most important remaining problems for the Linux audio world. VST plugins are ubiquitous in the Win/Mac audio worlds, they are employed extensively in professional and desktop music software, and it may be no exaggeration to claim that the VST standard has revolutionized computer-based creation of music and sound. Given its great popularity this writer believes that stable VST support would give Windows users a compelling reason to try Linux as an alternate or replacement platform, especially if they have a sizeable investment of money and experience in their collection of VST plugins.

To a degree, VST support under Linux already exists. The FST and DSSI projects provide utilities to open and run Windows-specific VST plugins. Those projects do work, but they are dependent on WINE. As WINE itself has become a more stable dependency the FST and DSSI bridges have become viable mechanisms for internal VST support in programs such as Ardour and Rosegarden. However, significant problems remain, particularly regarding multiple plugin instances and MIDI control.

Developer Lucio Asnaghi has created his JOST software to provide seamless support for VST plugins under Linux, but his design philosophy differs radically from the FST and DSSI projects in two key aspects. First, JOST has no WINE dependencies. More significantly, instead of acting as a emulation environment for native Windows VST plugins JOST hosts native Linux VST plugins. Yes, I mean VST plugins that can be compiled for running under Linux.

JOST

JOST (Jack hOST) is a standalone host for VST plugins that have been ported to Linux. The project is quite new, and at this time it's best to consider JOST development to be at the proof-of-concept stage. It works, but setup and usage is a little complicated. Here are the steps necessary to use and test JOST :

1. Download and (optionally) compile the jost binary.
2. Download and (optionally) compile some ported VST plugins.
3. Copy or rename the jost binary to the name of a ported plugin, minus the .so extension.
4. Start the JACK audio server.
5. Invoke the newly-named binary, e.g. ./Transverb.
6. Make audio and MIDI client connections (in QJackCtl or a similar utility).
7. Rock out (optional).

The plugin and the jost executable must exist in the same directory. Thus, if I have jost and Transverb.so (a reverb effect plugin from DestroyFX) in one directory :

    cp jost Transverb

I start JACK, then I can run the plugin as a standalone application :

    ./Transverb

Figure 1 illustrates the results.

Lucio has collected and compiled various plugins from VST developers mda and DestroyFX for use with JOST. Sources and precompiled binaries are available from the JUCEtice Web site.

Building JOST from source code is not difficult, but it requires the JUCE framework, which is also not difficult to compile and install. Both packages require the premake utility and an up-to-date C/C++ compiler. JOST further requires version 2.3 of the VST SDK. Potential builders should note that JOST is open-source software that is freely available, but it is not licensed under the GPL.

I tested JOST with some ported plugins under Dynebolic 2.3 on an 800 MHz machine. The Transverb plugin worked well, but the current port is incomplete (I missed its randomization function). I also tested the Rumpelrausch ZR3 VSTi plugin, a very good drawbar organ emulator. VSTi plugins are typically instruments that require MIDI input for their operation. JOST supplies the necessary MIDI I/O ports, identified as Juce Midi Input/Output by QJackCtl.

Lest any reader get carried away by enthusiasm, it is highly unlikely that many commercially developed VST plugins will be ported to Linux any time soon. The work done so far has been possible thanks to the original developers consenting to release their source code openly, and it is unwise to expect the same behavior from all developers. However, JOST is proof of the concept that VSTs can be compiled for and run natively under Linux, and perhaps it will be convincing enough to sway a few more developers into an open-source orbit.

Jorgen Aase's energyXT2 also hosts native Linux VST plugins. Figure 2 shows off energyXT2 working with the synth4 plugin.

The VST Problem

As I mentioned, FST and DSSI depend upon WINE to emulate a Windows environment sufficiently believable to a native Windows VST plugin. Alas, WINE may change its codebase and leave those systems stranded, but depending on WINE is the least of the difficulties faced by any prospective system for VST plugin support under Linux. The greater problem is the license for the VST SDK, particularly this section :

"2. The Licensee has no permission to sell, licence, give-away and/or distribute the VST PlugIn Interface technology or parts of it in anyway, on any medium, including the Internet, to any other person, including sub-licensors of the Licensee or companies where the Licensee has any involvement. This includes re-working this specification, or reverse-engineering any products based upon this specification."

That passage expressly forbids the free distribution of the SDK source code, excluding it from agreement with the terms of the GPL, nor can Linux-specific improvements be added to the official codebase. If the SDK sources were truly libre software then the various VST support applications now available for Linux could become standard items in Linux distributions. VST support could become more stable and robust, lending Linux greater attraction to users coming from the Windows audio software world. Libre license-compliant native and/or emulated support seems to have no downside, and it's even possible that more commercial VSTs might be sold.

Back to reality. Michael Bohle's announcement of JOST's initial release caused a lengthy commotion on the Linux audio mail lists, with much commentary upon the licensing and other development issues. Alas, no conclusion was reached regarding how to lobby for a change of license for the VST SDK, but the fact remains that as more Windows users contemplate a change of operating system, the musicians among them will want the option to use VST plugins under Linux. It would be a shame if a mere licensing issue prevents them from enjoying that option.

Outro

I'll return in somewhat less than a fortnight with more news from the world of Linux sound and music software. Until then, keep your heads ringing.