This is a visualization based on on the monoscope output plugin from alsaplayer. The monoscope output plugin was written primarily by Ralph Loader. This implementation is taken from alsaplayer version 0.99.54, at http://www.alsaplayer.org/ Note: only one instance of this plugin may be created at a time: it has a lot of static data. This should be fixed (and it shouldn't be hard to do so, either).