“…Unfortunately, only a few works have 45 exploited spatio-temporal features or motion information in this problem until now [11, [15][16][17]. In these cases, the spatio-temporal feature evaluated was Space-Time Interest Points (STIP) [17], Dense Trajectories [18], Temporal Robust Features (TRoF) [16], and the motion information coming from a statistical analysis of the MPEG Motion Vectors. Particularly, in [16], the experiments 50 confirmed that the incorporation of spatio-temporal information leads to more effective video-pornography classifiers.…”