Motif Spotting in an Alapana in Carnatic Music

This work addresses the problem of melodic motif spotting, given a query, in Carnatic music. Melody in Carnatic music is based on the concept of raga. Melodic motifs are signature phrases which give a raga its identity. They are also the fundamental units that enable extempore elaborations of a raga. In this paper, an attempt is made to spot typical melodic motifs of a raga queried in a musical piece using a two pass dynamic programming approach, with pitch as the basic feature. In the first pass, the rough longest common subsequence (RLCS) matching is performed between the saddle points of the pitch contours of the reference motif and the musical piece. These saddle points corresponding to quasi-stationary points of the motifs, are relevant entities of the raga. Multiple sequences are identified in this step, not all of which correspond to the the motif that is queried. To reduce the false alarms, in the second pass a fine search using RLCS is performed between the continuous pitch contours of the reference motif and the subsequences obtained in the first pass. The proposed methodology is validated by testing on Alapanas of 20 different musicians.