Long considered one of the greatest challenges for Artificial Intelligence methods, videos are now becoming ever-increasing relevant as one of the most effective and pervasive information mediums, mainly due to the constant growth of user-generated content available online and to the rising presence of autonomous cameras both in public and private places. The act of processing and getting useful knowledge from videos presents several criticalities due to the peculiar characteristics of such a medium which merges together spatial and temporal information; nevertheless, the applied fields of use are extremely varied, indicating its potential, and the most diverse feature descriptors and Deep Neural Networks models have been proposed over time.