Section: New Results

Adaptive Synchronization Strategies for Automatic Accompaniment

José Echeveste developped several synchonization strategies in the framework of his PhD thesis. Their formalization is based on a dynamic real-time extension of the time map formalism, going beyond state-of-the-art where the largest body of literature on time maps is devoted to static functions, defined and known at all times before any manipulation is done. Only the latest work of Liang and Danneberg (2011) have considered dynamic time map in the synchronization problem. However their approach suffer from a consistency drawback: the convergence of the tempo depends on the events occuring during the catching trajectory. In our approach we have developped a lag-depend formulation of the catching trajectory, which is insensitive to the actual events. This adaptive strategy consider only the deviation in tempo and position and is otherwise context-independant, it ensure convergence both in position and tempo, and it is efficient: there is no need to a fine sampling clock to discretize the time evolution: as long as the prediction time map do not change, delays are computed only once using the accompaniment time map. Our approach is general enough to handle various important issues in automatic accompaniment: latency management, integration of non constant tempo specifications in the score (accelerando, ritardanto, rubato...), handling of missing events, etc. Synchronization strategies have been fully formalized in the PhD report of José Echeveste [8] together with a complete Antescofo core including other dynamic constructions.