1. A method of summarizing a source video sequence, said method comprising: obtaining a source video being a sequence of video frames which presents two or more source objects that are moving relative to a background; receiving features descriptive of selected source objects presented in the source video sequence over a selected time interval, wherein the source objects represent moving objects appearing in the source video; clustering the source objects into clusters such that each one of the clusters includes source objects that are similar in respect to one of the features or a combination of the features; selecting one or more of the clusters, and further selecting source objects only from the selected one or more clusters generating synopsis objects by sampling respective source objects; generating a synopsis video only from the selected synopsis objects wherein the synopsis video has a playing time which is shorter than the playing time of the source video, wherein two or more synopsis objects which are played at least partially simultaneously in the synopsis video, are generated from source objects that are captured at different times in the source video, wherein two or more synopsis objects which are played at different times in the synopsis video are generated from source objects that are captured at least partially simultaneously in the source video.