1. A computer implemented method for identifying a first collection of recordings, each recording having a temporal position in the first collection, the method comprising: retrieving a temporal length for each of M recordings in the first collection, each temporal length being based on the temporal position of the corresponding one of the M recordings, wherein M is a positive integer value; generating M track vectors for the M recordings, each of the M track vectors including N vector elements, each of the N vector elements being a function of the temporal length for the corresponding recording, wherein N is a positive integer value; generating an M×N matrix based on the track vectors generated for the plurality of recordings; decomposing the matrix into a set of basis vectors; and storing one or more of the basis vectors as an identifier for the first collection.