The Matroska (MKA) is a free container format based on an open standard. It can hold an unlimited number of video, audio, image or subtitle tracks within a single file. Matroska is intended to serve as a universal format to store common multimedia content such as movies or TV shows. It is conceptually similar to other containers such as AVI, MP4 or ASF but unlike them is completely free. Matroska video files are identified by their MKV extension and those with an MKA extension are audio-only files.