The Continuator: Musical Interaction With Style

1. The Continuator: Musical Interaction With Style Presented by Ching-Hua Chuan ISE 575, Spring 2007, March 29, USC

2. Introduction • Real-time interactive musical instruments that are able to produce stylistically consistent music. • The system learns music styles automatically, and is seamlessly integrated in the playing mode of the musicians. • Interactive v.s. imitation systems

3. Inside the Continuator • Architecture • Automatic learning and generation • Prefix trees with indexing scheme • Variable-order Markov models • Reduction functions • Polyphony and rhythm • Interactive musical instrument • Biasing Markov generation

4. Architecture

5. Input seq # 2: {A B B C} Prefix Trees (learning the sequence) Input seq # 1: {A B C D} 1 2 3 4

6. Input seq. 1: {A B} • continuation_list = {3, 7} • randomly pick B Variable-order Markov models(generating the sequence) Start again with {A B B}  continuation_list = {8} Learned prefix trees • Start again with {A B B C} • no match • continuation_list({B C}) = {4} Learned seq. :{A B C D A B B C } 1 2 3 4 5 6 7 8 Ending seq = {A B B C D}

7. Less refined reduction function. (pitch region instead of pitch) - learned: {PR1 PR1 PR2 PR3 PR5} - Input: {PR1 PR1 PR2} - Continuation = {PR3}, which is G in this case. • Hierarchy of reductions - pitch * duration * velocity - small pitch region * velocity - small pitch regions - large pitch regions Cont’d Reduction Functions • No continuation is found. learned Input

8. Polyphony and Rhythm • Polyphony: legato v.s. musical cluster • Rhythm (jazz and popular music) - Natural, linear, input rhythms - Fixed metrical structure chord legato Fixed metrical structure

9. Biasing Markov Generation • Weighting the nodes according to how they match the external input. S=1, we get a musical automaton insensitive to the musical context, S=0, we get a reactive system which generates the closest musical elements to the external input it finds in the database.

10. Experiments Bernard Lubat The Continuator and children Gyorgy Kurtag Claude Barthelemy Video from http://www.csl.sony.fr/Research/Experiments/Continuator/index.php

11. Demo • Let’s play with it!