1. A method comprising: by one or more computing devices, accessing a first feature vector representing a video-content object corresponding to a node in a social graph of a social-networking system, wherein: the video-content object comprises frames and audio and is associated with text; the first feature vector is based on one or more of the frames of the video-content object; and the social graph comprises a plurality of nodes and edges connecting the nodes; by one or more computing devices, accessing a second feature vector representing the video-content object, wherein the second feature vector is based on at least some of the text; by one or more computing devices, accessing a third feature vector representing the video-content object, wherein the third feature vector is based on one or more portions of the audio; by one or more computing devices, determining a fourth feature vector representing the video-content object, wherein the fourth feature vector is based on a combination of the first, second, and third feature vectors; and by one or more computing devices, determining a context of the video-content object based on the fourth feature vector and social-graph information based at least in part on one or more nodes or edges connected to the node corresponding to the video-content object.