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The name of the instrument (ie, MIDI module) being used to play the track. This may be different than the Sequence/Track Name. For example, maybe the name of your sequence (ie, Mtrk) is "Butterfly", but since the track is played upon a Roland S-770, you may also include an Instrument Name of "Roland S-770".

It's best to put one (or more) of this event at the beginning of an MTrk to provide the user with identification of what instrument(s) is playing the track. Usually, the instruments (ie, patches, tones, banks, etc) are setup on the audio devices via MIDI Program Change and MIDI Bank Select Controller events within the MTrk. So, this event exists merely to provide the user with visual feedback of what instruments are used for a track.