Tempus Ex Machina: How Antescofo coordinates musical time between human and machine
Writing, reading and interpreting have been pillars of our languages for millennia. These vectors of communication have also existed in art music for several centuries. through scores. One of their specific dimensions is the need to write and interpret time, or rather times. There is, of course, absolute time, the physical time in which music is played. But there is also the logical time of the score, with its quarter notes, eighth notes, etc., the more hidden time of the repetition of phrases, themes or motifs, the time induced by the dynamic organization of tempi and articulations by the performers, and so on. Understanding and managing these multiple beats is central to the composition and execution of works in mixed human/machine music. In the past, the machine part was performed rigidly, with tempo and articulation fixed in the magnetic medium or computer program. But the automatic tracking of scores in real time, and other algorithmic advances, have reversed the situation, freeing the performers to play a temporally mobile computer music. Understanding the relationship between the various times is also necessary to provide tools for composing the computer part in a much simpler and richer way, using new algorithmic and linguistic approaches that are no longer restricted to the classical linear score. All these aspects are addressed by the Antescofo system from IRCAM and Inria. Using a precise temporal language inspired by synchronous languages such as Esterel and Lustre, this system associates the start and stop of complex electronic music generation algorithms with events detected by its listening machine. Antescofo also makes it possible to specify various time-tracking strategies for tempo variations, and to compensate for the inevitable errors of the instrumentalists or the listening machine, which is central to the concert. Antescofo is used extensively by many composers, including Philippe Manoury. It will soon also be available to facilitate music learning.
