A control message is a MIDI event that records performance actions such as starting or releasing a note. Note-on and note-off messages carry pitch values, while velocity is handled separately to represent playing dynamics. Together, these events preserve timing, pitch, articulation, and expressive force for playback or model training. section 14.1.1
A performance sequence reduces to four event types:
- note_on starts a note at a pitch from 0 to 127; for example, 74 represents D5. section 14.1.1
- velocity records dynamics separately, with original values from 0 to 127 reduced to 32 bins. section 14.1.1
From performance event to model input
A note-on event at approximately 1.03 seconds with pitch 74 and velocity 86 becomes a time-shift event, a binned velocity event, and a note-on event with value 74. The resulting event sequence can then be converted into indexes for a music Transformer. section 14.1.1
