Copy a song from a songbook by dragging notes, chords and other symbols to staff lines until you have the same picture as in the songbook. Choose a style and a melody instrument and play. Computer aided music arranging was never so simple!
MPL is a tool to make changes to MIDI files in batch and to process (send and receive) MIDI messages in real time. You can use it to automate your MIDI file editing work. Or build your own real time MIDI tools, like sequencers or arpeggiators.