AGNULA

The AGNULA project, the name of which is an acronym for A GNU/Linux Audio Distribution, has been created to design and build aversion of Linux specifically for professional musicians and recording engineers. AGNULA is a consortium of several European universities, the Red Hat Linux company and the Free Software Foundation. The idea is that all the software needed for professional audio use will be on one set of CD-ROMs, which will include a tuned Linux operating system. This doesn't mean that it just comes with an extra driver or two and a few tweaked settings here and there. While Windows and Mac OS will always remain general-purpose systems, the open source philosophy means that Linux can be customised for individual requirements at the most fundamental level.

As far as the musician and pro audio user is concerned, there are four key components of a Linux system. The kernel — the actual Linux core — can be customised for very low latency, which is essential for any kind of multitracking or synchronisation. The Advanced Linux Sound Architecture or ALSA provides drivers for pro and consumer soundcards (see table on the last page of this article). JACK is the internal audio system which connects between applications at a low level, while LADSPA stands for the Linux Audio Developers Simple Plug-in API. LADSPA is a bit like Steinberg's VST plug-in system, but in an open source style — the many VST plug-ins available to download from the Internet at no cost don't generally include source code.

The individual components of AGNULA are already available, but the project is creating two integrated packages based on either the Red Hat Linux or Debian distributions. Each distribution (or version) of Linux has its followers: the Red Hat company is more business-orientated, but Debian is built by volunteers and has a reputation for very high quality. While each distribution has a slightly different way of doing things, they remain broadly compatible. Published standards and source code availability mean that a program created on one distribution is usually available to all the others.

Beta versions of the two AGNULA distributions are due shortly, with stable releases expected in 2003. In the Linux community, the widest possible testing of beta versions is encouraged to enable high standards of quality control. With modern hard disks being so large, there is usually plenty of room to install Linux in its own partition, and keep the existing operating system intact. Disk partitioning is well worth doing for Windows machines anyway, since it keeps your sound data well away from the operating system, and therefore safe if you ever have to reformat your C drive. Most current Linux distributions feature a wizard to help you set up partitions and dual-booting, so it's likely that AGNULA will too.

Since AGNULA will cost very little to try out, except perhaps in the time taken to learn about the software, there's not much to lose. Both AGNULA distributions will be free for download, intially built for the Intel x86 architecture (Pentium and Athlon), and will be probably be available on CD-ROM too. The project also plans to make the distributions available for PowerPC chips and the new generation of 64-bit processor systems later next year.

The drawback to any new desktop operating system is usually a lack of applications. Fortunately, although Linux is relatively new to the sound industry, it has already been under development for a decade. While Windows and Mac applications can run under Linux on the relevant processor using various kinds of emulator and virtual machine, lots of native Linux audio software is already available. The full range of programs available on other platforms is covered, from notation editors to DJ software. Many excellent free music applications for Linux are stable or close to stable release, and will be included with AGNULA. Here are just a few of them:
Rosegarden is a MIDI + Audio sequencer which includes notation and audio editing. Version 4 is probably the closest native equivalent to Cubase for Linux, and has recently been released as a beta after two years of active development. Unlike Windows and Mac OS where there is only one kind of desktop for each system, Linux developers have a wide choice of graphical toolkits to build applications from. Rosegarden is designed with the KDE interface, but it will run on any Linux machine with the right libraries installed. Rosegarden features include MIDI and audio playback and recording using ALSA and JACK, real-time audio plug-in effects via LADSPA, score, piano-roll and track overview editors, high-quality score printing and MIDI file input/output.

Software engineer and musician Richard Bown comes from London, and is one of the lead developers on the Rosegarden project. He's been working on Rosegarden over the last seven years, but until recently he still needed to use Windows or a Mac to record and produce his music. While making his last album, Richard wondered if Rosegarden would one day allow him to do the same on Linux, and now believes it can.

When Rosegarden was originally written for UNIX machines about 10 years ago, Linux was just beginning to emerge, and it seemed a natural fit. Since there were already plenty of good sequencers and notation editors available for the Mac and Windows, the Rosegarden team concentrated on making something new. "We're now establishing Rosegarden as a product in its own right and hope to make it something that will make music people start to think about Linux more seriously," comments Richard. "If studios or individuals want a boxed solution they can approach us and we can put it together for them, but it's true that anyone can package and distribute our software. AGNULA doesn't need our permission and we don't get any explicit kickback apart from a little publicity. As a small company we couldn't afford to develop, market and distribute a closed-source solution. As an open-source project we do sign away our rights to saying what people do with the source code but we do gain testers, developers, marketers, friends and a warm feeling along the way."

Richard adds "The warm glow bit is important to me. While I'd like to be paid to write this code, I'm also proud to be a part of it for what it is. The fact that Rosegarden is now becoming a quality solution to rival those on other platforms is a great bonus."
Ardour is a multi-channel hard disk recorder and digital audio workstation, capable of the simultaneous recording of 24 or more channels of 32-bit audio at the 48kHz sample rate. Currently in heavy development, Ardour visually resembles the UNIX software available on platforms such as SGI. Linux machines running Ardour are intended to replace dedicated studio hardware such as the Mackie HDR, the Tascam 2424 and ADAT systems. Ardour is also intended to rival proprietary software applications such as Pro Tools, Samplitude, Logic Audio, Nuendo and Cubase VST. It supports MIDI Machine Control, and can therefore be used with any MMC-compliant digital mixer.
Audacity is a deceptively simple audio editor and multitrack hard disk recorder. It has a clean interface with large buttons in the style of a tape machine, but very precise edits are possible by drawing envelopes directly on the waveform using the mouse. Audacity breaks large audio files into small chunks for its native file format, which makes multitrack recording and editing quite feasible on modest hardware.

An added bonus with Audacity is that the program is available not just for Linux, but for Mac and Windows too. This means that mixed-computer environments can have a standard free format for multitrack recordings. Version 1.0.0 is the current stable release, while the development version 1.1.0 contains many new features, including support for 24-bit and 32-bit samples with automatic real-time resampling. The new version also includes LADSPA plug-in capability, an XML-based project format and full Ogg Vorbis (a licence-free alternative to MP3) import/export.
Sweep, at first glance, is a conventional multi-channel audio file editor. However, a virtual stylus instead of the normal cursor makes the program quite unique, on Linux at least. The idea is that you can scrub through a file to hear the exact place where you want to make an edit — but the virtual stylus, known as Scrubby, has been programmed with the physics of a real turntable. Throwing the mouse to the left results in a spin-back effect, decelerating Scrubby to a full stop.

This makes Sweep possibly the first audio program that could be used both in a serious production environment and as a performance tool for fully digital DJs. It was developed with the support of animation studio Pixar, who presumably needed a high-quality audio editor which could be used on Linux and Sun UNIX workstations (Sweep is available freely for both). This application might be the first benefit to trickle down from the big movie studios to the Linux audio community, but it almost certainly won't be the last.