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.
See more at Wikipedia.org...