Abstract: A musical audio composition is generated based on a content library. The library is a collection of sequences and instruments. Sequences are partial musical compositions, while instruments are groups of audio samples. Instruments are made of audio data and musical data describing the events recorded in the audio. The process begins by reading the library. A new chain is created. A succession of sequences are selected to create a series of segments in the chain. The events in the selected sequences determine the selection of instruments. Algorithms determine the final arrangements and exact modulations of source audio to target outputs. The source audio are modulated, mixed and output as a stream of audio data. Finally the selections and events of the finished segment are output as metadata. An unlimited number of segments can be fabricated in series, each building and evolving from the preceding segments in the chain.