Mauricio Toro

Mauricio Toro

In this review, it is explained and compared different software and formalisms used in music interaction: sequencers, computer-assisted improvisation, meta- instruments, score-following, asynchronous dataflow languages, synchronous dataflow languages, process calculi, temporal constraints and interactive scores. Formal approaches have the advantage of providing rigorous semantics of the behavior of the model and proving correctness during execution. The main disadvantage of formal approaches is lack of commercial tools.

Mauricio Toro, Myriam Desainte-Catherine

Multimedia scenarios have multimedia content and interactive events associated with computer programs. Interactive Scores (IS) is a formalism to represent such scenarios by temporal objects, temporal relations (TRs) and interactive events. IS describe TRs, but IS cannot represent TRs together with conditional branching. We propose a model for conditional branching timed IS in the Non-deterministic Timed Concurrent Constraint (ntcc) calculus. We ran a prototype of our model in Ntccrt (a real-time capable interpreter for ntcc) and the response time was acceptable for real-time interaction. An advantage of ntcc over Max/MSP or Petri Nets is that conditions and global constraints are represented declaratively.

Mauricio Toro, Myriam Desainte-Catherine, Julien Castet

Software to design multimedia scenarios is usually based either on a fixed timeline or on cue lists, but both models are unrelated temporally. On the contrary, the formalism of interactive scores can describe multimedia scenarios with flexible and fixed temporal relations among the objects of the scenario, but cannot express neither temporal relations for micro controls nor signal processing. We extend interactive scores with such relations and with sound processing. We show some applications and we describe how they can be implemented in Pure Data. Our implementation has low average relative jitter even under high cpu load.

Mauricio Toro

In this work we explain the implementation of event-driven real-time interpreters for the Concurrent Constraint Programming (CCP) and Non-deterministic Timed Concurrent Constraint (NTCC) for- malisms. The CCP interpreter was tested with a program to find, concurrently, paths in a graph and it will be used in the future to find musical sequences in the music improvisation software Omax, developed by the French Acoustics/Music Research Institute (IRCAM). In the other hand, the NTCC interpreter was tested with a music improvisation system based on NTCC (CCFOMI), developed by the AVISPA research group and IRCAM. Additionally, we present GECOL 2, a wrapper for the Generic Constraints Development Environment (GECODE) to Common LISP, de- veloped to port the interpreters to Common LISP in the future. We concluded that using GECODE for the concurrency control avoids the need of having threads and synchronizing them, leading to a simple and efficient implementation of CCP and NTCC. We also noticed that the time units in NTCC interpreter do not represent discrete time units, because when we simulate the NTCC specifications in the interpreter, the time units have different durations. In the future, we propose forcing the duration of each time unit to a fix time, that way we would be able to reason about NTCC time units as we do with discrete time units.

Mauricio Toro, Camilo Rueda, Carlos Agón et al.

Writing multimedia interaction systems is not easy. Their concurrent processes usually access shared resources in a non-deterministic order, often leading to unpredictable behavior. Using Pure Data (Pd) and Max/MSP is possible to program concurrency, however, it is difficult to synchronize processes based on multiple criteria. Process calculi such as the Non-deterministic Timed Concurrent Constraint (ntcc) calculus, overcome that problem by representing multiple criteria as constraints. We propose using our framework Ntccrt to manage concurrency in Pd and Max. Ntccrt is a real-time capable inter- preter for ntcc. Using Ntccrt externals (binary plugins) in Pd we ran models for machine improvisation and signal processing.

Mauricio Toro, Camilo Rueda, Carlos Agón et al.

In this paper we present Gelisp, a new library to represent musical Constraint Satisfaction Problems and search strategies intuitively. Gelisp has two interfaces, a command-line one for Common Lisp and a graphical one for OpenMusic. Using Gelisp, we solved a problem of automatic music generation proposed by composer Michael Jarrell and we found solutions for the All-interval series.