Jon Jon - 3 months ago 31
Java Question

Convert Midi Note Numbers To Name and Octave

Does anybody know of anything that exists in the Java world to map midi note numbers to specific note names and octave numbers. For example, see the reference table:

http://www.harmony-central.com/MIDI/Doc/table2.html

I want to map a midi note number 60 to it's corresponding note name (MiddleC) in octave 4. I could write a utility class/enum for this, but it would be rather tedious. Does anybody know of anything?

I'm specifically using this to write a Tenori-On/Monome clone in Java, so far so good...

Solution

This was what I ended up using:

String[] noteString = new String[] { "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" };

int octave = (initialNote / 12) - 1;
int noteIndex = (initialNote % 12);
String note = noteString[noteIndex];

Answer

I'm not convinced your suggestion is that tedious. It's really just a divide-and-modulo operation, one gets the octave, the other gets the note.

octave = int (notenum / 12) - 1;
note = substring("C C#D D#E F F#G G#A A#B ",(notenum % 12) * 2, 2);

In real Java, as opposed to that pseudo-code above, you can use something like:

public class Notes {
  public static void main(String [] args) {
    String notes = "C C#D D#E F F#G G#A A#B ";
    int octv;
    String nt;
    for (int noteNum = 0; noteNum < 128; noteNum++) {
      octv = noteNum / 12 - 1;
      nt = notes.substring((noteNum % 12) * 2, (noteNum % 12) * 2 + 2);
      System.out.println("Note # " + noteNum + " = octave " + octv + ", note " + nt);
    }
  }
}