A MIDI event that carries the MIDI note off message tells a MIDI device that at a certain time some and on a certain channel some note should be released and should stop sounding.
This message belongs to the category of MIDI voice messages.
This message consists of three bytes of data. The first byte is the status byte and has hexadecimal values between 0x80 and 0x8F. The high nibble of the status byte is 8, which tells the MIDI device that this is a note off message. The low nibble of the status byte is between 0 and F (0 and 15 in decimal values) and points to one of the 16 MIDI channels. Two bytes follow the status byte. The first byte after the status byte has values between 0x00 and 0x7F (0 and 127 in decimal values) and shows which note should be released. A value of 0x3C (60 decimal) signifies the note middle C. Higher values represent higher notes and lower values represent lower notes, where a change of 1 is a change of one semitone. The second byte after the status byte is the velocity with which the note should be released, where 0 is the slowest and 127 is the fastest.
The following is an example of a MIDI note off message.
0x83 0x3E 0x78
The status byte 0x83 shows that this is a note on message and that the note should be released on channel 3. The note is 0x3E (62 decimal), which is D above middle C. The note should be released with velocity 0x78 (120 decimal).
Musical Instrument Digital Interface (MIDI)