+ A video file is a <dfn>container</dfn>. It usually contains one
+ <dfn>video track</dfn> and one or more <dfn>audio tracks</dfn>.
+ How these tracks are stored in the file is defined by the
+ <dfn>file format</dfn>. Common formats are
+ avi, mov, ogg, mkv, mpeg, mpeg-ts, mp4, flv, or vob.