1. A computer-implemented method of creating a composite video, the method comprising: accessing a database storing volumes from a plurality of digital videos, each volume being a spatio-temporal segment of one of the videos and having a start time and an end time within the video, wherein a spatial extent of each volume is less than an entire frame of the video; providing, to a client device, indicia for a plurality of the volumes; receiving, from the client device, selections of a subset of the indicia, thereby selecting a corresponding subset of the plurality of the volumes; retrieving, from the database, the volumes of the subset; compositing the retrieved volumes to form a composite video.