An output video is created by at least two cameras recording respective source videos, each having multiple video frames containing video objects imaged by the cameras corresponding to multiple instances of one or more respective source objects traversing the site. Output video objects having a new start display time are computed such that a total duration of display times of all video objects from all source videos is shorter than a cumulative duration of the source videos. The output video objects or graphical representations thereof are rendered at new display times over a background image such that (i) instances imaged by different cameras at different times are represented simultaneously; (ii) at least two output video objects originating from a common camera have different relative display times to their respective source objects; and (iii) in at least one location there are represented instances imaged by two different cameras.