Isadora

"Isadora is a graphic programming environment for Macintosh and Windows that provides interactive control over digital media, with special emphasis on the real-time manipulation of digital video.

Because every performance or installation is unique, Isadora was designed not to be a "plug and play" program, but instead offers building blocks that can be linked together in an almost unlimited number of ways, allowing you to follow your artistic impulse.

Isadora was initially created to facilitate the performances of Troika Ranch, a media intensive dance company co-directed by Isadora's creator, composer and media-artist Mark Coniglio. It reflects over 15 years of practical experience with realtime interaction.

It also serves as the primary tool used in Troika Ranch's Live-I Workshops. It is designed to be easy to learn for those new to the world of real-time interaction. The titles and values of every actor are visible to the user (though they can be hidden if you desire). Help is available for all actors and their inputs and outputs from within the program. Isadora is accompanied by a complete manual that includes numerous tutorials and example files to get you started."

Quote from Troika Tronix web site

http://www.troikatronix.com/isadora.html

Max/MSP/Jitter 

An interactive graphical programming environment for music, audio, and media.

For over two decades, people have been using Max/MSP/Jitter to make their computers do things that reflect their individual ideas and dreams. Compatible with Mac and Windows, Max/MSP/Jitter provides true cross-platform authoring and a free runtime version.

Max/MSP/Jitter is three things:

1. Max, a graphical programming environment that provides user interface, timing, communications, and MIDI support
2. MSP, for real-time audio synthesis and DSP
3. Jitter, for video and matrix data processing

http://www.cycling74.com/