What is "music visualization"

Music visualization or music visualisation, a feature found in electronic music visualizers and media player software, generates animated imagery based on a piece of music. The imagery is usually generated and rendered in real time and in a way 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.