Standard MIDI (Musical Instrument Digital Interface) file used by MIDI hardware devices as well as music authoring and playback programs; contains music data, such as what notes are played, when they are played, how long each note is held, and the velocity of each note.

MIDI files are used for interoperability between different types of software programs and hardware devices. They also may include controller data for a device. For example, a MIDI file can be used to switch instruments on a MIDI program or device. MIDI files can be played back using software instruments, but they do not contain actual audio data. MIDI files also use the .MID file extension.