Free Software and Multimedia

Each presentation was scheduled for 30 minutes, with a five to ten minute space between each presentation reserved for questions from the audience. It is a great credit to the speakers that they were all well prepared and kept their presentations within the allotted time. I should also note that all the presentations were well received by the audience.

The conference started promptly at 9:30 Saturday morning with Marco Trevisani's introduction to the Demudi project. The project name is an acronym for the Debian Multimedia Distribution, a Linux distribution built upon an existing Debian system and optimized for multimedia performance. The distribution will include a collection of multimedia applications and a Linux kernel optimized for low audio and video latency times.

An FTP site will be established for on-line access, and the Debian apt-get tool will be employed for package updates over the Internet. An alpha version of the distribution is planned for the International Computer Music Conference (ICMC2001 will be held this September in Havana, Cuba).

(Note: A private meeting focused on Demudi was held the day before the workshop, attended by only the workshop participants. Material regarding that meeting is presented in an addendum to this article.)

As the President of FSF Europe, the official European sister to Richard Stallman's Free Software Foundation, Georg Greve was eminently suited to present the definition and history of the free software movement. Mr. Greve clarified and discussed the content and purport of various open-source licenses (e.g., GPL, FreeBSD, MIT) in the context of the FSF's Four Freedoms, defined by Richard Stallman as:

This part of Mr. Greve's presentation was perhaps the most interesting. Licensing issues are a concern to many developers, as was evidenced in the lively question and answer period that followed. Mr. Greve's detailed knowledge of the various open-source licenses certainly clarified a number of questions regarding the legal issues surrounding the protection of free software.

Mr. Greve summarized the current activities of FSF Europe (suffice to say he is a busy man these days) and finished with an overview of the FSF's plans to expand into other areas of the world, particularly India and China.

XDV (Verein für experimentelle Datenverarbeitung) is a group of audio and visual artists working together in Vienna. Their activities include live internet radio streams, web art, and the development and use of the Pd sound synthesis/processing and composition environment.

Pd is a graphic "patching" environment for the creation of audio/visual instruments. The user selects various kinds of objects (DSP modules, synthesis methods, soundfile record/playback controls, video and 3-D graphics, etc.) and connects them together to create a signal and control path known as a patch. Patches can be nested within patches, making it possible to create complex instruments with relatively simple control interfaces.

Günter Geiger demonstrated the Linux port of Pd along with GEM, an OpenGL graphics library. He began with a simple FFT display of a real-time input signal, quickly evolving the display into a complex and fascinating "waterfall" graphics display of the input's frequency content. Günter also showed how Pd coordinates audio and MIDI I/O with the display and manipulation of 3-D graphics in real time, and his final flourish was a tantalizing demonstration of Pd's recently-added video capabilities.

Open-source development is certainly not restricted to any particular platform. Gabriel Maldonado has developed a variety of useful opcodes and extensions for the Csound audio synthesis/processing environment. His DirectCsound is a greatly enhanced version of Csound for Windows, and many of his opcodes have been added to the canonical Csound source distribution at Bath UK. Gabriel has placed his extensions for DirectCsound under the GPL, and he has worked closely with Nicola Bernardini on integrating his opcodes into the unofficial Linux Csound.

Mr. Maldonado demonstrated his recent Csound opcodes that utilize the FLTK graphics library to provide an intrinsic set of widgets for Csound. These widgets include knobs and sliders for the construction of synthesizer interfaces, effectively giving the user the means to create a "softsynth" from Csound's powerful audio processing toolkit and its own set of graphic control elements.

The VMCI (Virtual MIDI Control Interface) was also presented. This software provides a set of virtual MIDI controllers (sliders, knobs, etc.) for use in adjusting Csound opcode parameters in real time. The VMCI software is free and licensed under the GPL, but it is written in Visual Basic, thus restricting its portability.