I'm not sure if this is the best forum, but: is there a repository of MIDI files somewhere that are free to use?
I'm thinking old songs, traditional tunes, etc.
Are they stored in xml, so they could be easily read, modified, and stored in new xml files, or how is this done? I'm thinking about taking a MIDI file which plays the melody on a piano, for example, and changing the file to play the melody with a flute, bagpipe, saxophone, etc. ... ?