NUT

NUT (file-extension: .nut) is a patent-free, multimedia container format originally conceived by a few MPlayer and FFmpeg developers that were dissatisfied with the limitations of all currently available multimedia container formats such as AVI, Ogg or Matroska. It aims to be simple, flexible, extensible, compact and error resistant, thus addressing most if not all of the shortcomings present in alternative formats, like excessive CPU and size overhead, file size limit, inability to allow fine grained seeking or restrictions on the type of data they can contain.