Provided are a device and method for processing a video. The device comprises: a receiving unit for receiving a video file corresponding to a video; a determination unit for determining a target region that needs to be extracted and a playing time period that needs to be extracted from a video picture; determining a sample corresponding to the playing time period from samples which constitute a video track according to the video file; describing region information about a sub-track comprised in a container according to the target region and sub-track data, and determining a sub-track corresponding to the target region as a target sub-track in at least one sub-track; and defining the container according to the sub-track data corresponding to the target sub-track, and determining an NAL package corresponding to the target sub-track in the sample corresponding to the playing time period, the determined NAL package being used to play a picture of the target region in the playing time period after being decoded. The embodiments of the present invention can effectively realize the extraction of a region picture from a video.