I ended support for iTunes visualizer development in 2017.
This page is for historical reference only.

iTunes is Apple’s audio player software. It organizes personal music collections and provides playback like a jukebox.

But it not only organizes and plays back audio. iTunes provides built-in visualization. By choosing “Show Visualizer” in the View menu, a visual show can be started that accompanies the music.

The menu item “Visualizer” lists all available visualizers as submenu items. The built-in “iTunes Visualizer” is always available, but other visualizers can be installed with ease as plug-ins.

On Mac OS X plug-ins are installed by placing the plug-in file inside the directory ~/Library/iTunes/iTunes Plug-ins/ (private access) or /Library/iTunes/iTunes Plug-ins/ (global access).
On Windows plug-ins are installed by placing the plug-in file inside a directory called “Plug-Ins”; this directory must be next to the iTunes.exe. If the directory does not exist you have to create it.

Some visualizer plug-ins can be customized with a configuration window. The menu item “Options...”, that is displayed under the list of available visualizers, offers access to the configuration window of the currently selected visualizer.

While developing a custom visualizer plug-in for iTunes, I noticed that no comprehensive sample code with basic functionality existed.
So I decided to set up an open source samplework for developing iTunes visualizers.

The open source project is called “VizKit”http://www.imagomat.de/vizkit/. The first version was released in June 2004.

The iTunes visualizer “Cover Version”http://www.imagomat.de/coverversion/ is based on the “VizKit” samplework.