An apparatus and method for determining the tempo and locating the downbeats of music encoded by an audio track performs a cross-correlation between a click track and a pulse track to indicate tempo candidates and between the click track and a series of pulses to determine downbeat candidates. The rhythm...http://www.google.com/patents/US6316712?utm_source=gb-gplus-sharePatent US6316712 - Method and apparatus for tempo and downbeat detection and alteration of rhythm in a musical segment
