4. The system for content recognition, search, and retrieval in visual data as set forth in claim 3 , wherein the hierarchical content descriptor module comprises a first level for detecting a set of salient spatiotemporal regions which are abstracted into a set of activity-agnostic spatiotemporal visual words, wherein a collection of each of the sets of activity-agnostic spatiotemporal visual words form a visual vocabulary.
5. The system for content recognition, search, and retrieval in visual data as set forth in claim 4 , wherein the hierarchical content descriptor module comprises a second level for modeling a set of motion trajectories of at least one moving object or salient blob in the unlabeled visual data.