I've been involved in open source multimedia through the xiph.org projects for seven years now and am knowlegeable about open source media, formats and tools. I've given 4 talks related to my open source media work in the past two years (see http://people.xiph.org/~giles/ for details)
I've also run a number of tutorial sessions, all in my previous life as an academic.
After two attempts at graduate school, Ralph took the exit ramp from physics into computers. He has been involved in Linux and open source since 1999, including the Utah-GLX driver project, the Xiph.org foundation for open multimedia, and Ghostscript. He works part time for Artifex Software, Inc., the commercial licensing agent for Ghostscript. He lives in Vancouver, Canada with his partner and child.