SIB file contains musical score data, not audio track of any kind. This file type is used by Sibelius music notation software, tool for composing music which offers support for MIDI input devices.

SIB files enable user to play and compose music on instruments supporting MIDI interface. It offers function to export data as a MIDI file in .MID format. Depending on version of the software, user can compose music for various instruments, print the sheet and share it on the Web.