Structural Change on Multiple Time Scales as a Correlate of Musical Complexity

We propose the novel audio feature structural change for the analysis and visualisation of recorded music, and argue that it is related to a particular notion of musical complexity. Structural change is a meta feature that can be calculated from an arbitrary frame-wise basis feature, with each element in the structural change feature vector representing the change of the basis feature at a different time scale. We describe an efficient implementation of the feature and discuss its properties based on three basis features pertaining to harmony, rhythm and timbre. We present a novel flowerlike visualisation that allows us to illustrate the overall structural change characteristics of a piece of audio in a compact way. Several examples of real-world music and synthesised audio exemplify the characteristics of the structural change feature. We present the results of a web-based listening experiment with 197 participants to show the validity of the proposed feature.