1. A method comprising: obtaining a source video containing a plurality of source objects; receiving features descriptive of at least some of the source objects; clustering the source objects into clusters, each cluster including source objects that are similar in respect to one of the features or a combination of the features; obtaining relevance level of the clustered source objects, respectively; generating synopsis objects by sampling respective clustered source objects; and generating a synopsis video having an overall play time shorter than the overall play time of the source video, by determining a play time for each of the synopsis objects, based at least partially on the respective relevance level, 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, and wherein said relevance level indicates a distance, on a feature space, between a synopsis object and said received features descriptive of at least some of the source objects.