Music visualization, a feature found in some media player software, generates animated imagery based on a piece of recorded music. The imagery is usually generated and rendered in real time and synchronized with the music as it is played.
Visualization techniques range from simple ones (e.g., a simulation of an oscilloscope display) to elaborate ones, which often include a plurality of composited effects. The changes in the music's loudness and frequency spectrum are among the properties used as input to the visualization.
Music/Audio players for personal computers became widespread in the mid to late 1990s as applications such as Winamp, Audion, and SoundJam. The first music visualization software was Cthugha, for DOS, released in 1994blank">http://www.afn.org/~cthugha/. Self-described as an "An Oscilloscope On Acid", Cthugha inspired similar implementations in Winamp, which was one of the first windows-based players to release a visualization _SDK. By 1999, there were several dozen freeware non-trivial music visualizers in distribution that were very highly regarded by computer, music, and art enthusiasts worldwide.
In particular, MilkDrop by Ryan Geiss, blank">G-Force by Andy O'Meara, and _Advanced Visualization Studio (AVS) by Nullsoft became the most popular music visualizations and still remain the most popular today. AVS is part of Winamp and has been recently open-sourced, and G-Force was licensed for use in iTunes and Windows Media Center and is presently the flagship product for Andy O'Meara's software startup company, SoundSpectrum. The real distinction between music visualization programs such as Geiss' MilkDrop and other forms of music visualization such as music videos or a laser lighting display is the visualization programs' ability to create different visualizations for each song every time the program is run. Also, unlike music videos and laser shows, visualization programs create a sense of personalization. The viewer receives a unique experience every time, creating an enhanced sense of wonder.
Music visualization programs originally looked more like effects seen in demos as seen in the demoscene, although lately the trend seems to move towards having a more professional VJ approach - incorporating the use of videos, live camera input and user interaction. One of the first visualizers to achieve that goal was the original BeatHarness plugin for Winamp. Noise Cradle is another visualization to provide such features.
