High Quality Content by WIKIPEDIA articles! The Matroska Multimedia Container is an open standard free container format, a file format that can hold an unlimited number of video, audio, picture or subtitle tracks inside a single file. It is intended to serve as a universal format for storing common multimedia content, like movies or TV shows. Matroska is similar in concept to other containers like AVI, MP4 or ASF, but is entirely open in specification, with implementations consisting mostly of open source software. Matroska file types are .MKV for video (with subtitles and audio), .MKA for audio-only files and .MKS for subtitles only. Matroska is an English word derived from the Russian word matryoshka. This is a play on the container aspect of the matryoshka as it is a container for visual and audio data. The loose transliteration may be confusing for Russian speakers, as the Russian word matroska actually refers to a sailor suit.