1. A method comprising: selecting a portion of data of an unknown work; detecting, by a computing system, each event in the portion of data of the unknown work, wherein an event is a perceptual occurrence in a work successively positioned in time; determining an event metric between each successive event in the portion of data in the unknown work; generating a list of event metrics between the events for the unknown work; comparing the list of event metrics for the unknown work to a list of event metrics for a known work; and determining the unknown work is a copy of the known work responsive to a match between the list of event metrics of the unknown work and the list of event metrics for the known work.