MIDI

1
MIDI

• Musical Instrument
• Digital Interface

2
Birth of MIDI

• 1982 - Dave Smith presents description of a
  universal synthesizer interface
• 1982 (December) - Prophet 600 released with first
  MIDI interface
• 1983 - MIDI 1.0 Specification

3
MIDI Connections

• IN
• OUT
• THRU

4
MIDI Channel Messages

• 31,250 bits/sec. in series
• Status byte
• Data byte
• Channel message - usually performance gesture

5
Note on message

• Status byte- 10010000
• First 1 represents status byte
• 001 states note on
• 0000 represents channel 1

6
Note on message

• Status byte is followed by two data bytes, such
  as 00111100 01000000
• The first 0s represent data byte
• The first data byte gives the note number, in
  this case 60 or middle C
• The second data byte gives the key velocity, here
  it is 64

7
Note off

• Running status
• Key velocity 0
• Note on 10010000 00111100 01000000
• Note off 10010000 00111100 00000000

8
Controllers

• 0 - 63 are continuous controllers
• 64-120 are switch controllers
• status byte for control change 10110000
• First data byte is control - 00000111
• Subsequent data bytes are values (running status)

9
Other Channel Messages

• Aftertouch - Channel or key
• Pitch bend - LSB and MSB
• Program Change

10
Quiz 1
Performance Action MIDI Message Playing a
key Releasing a key Pressing harder on a key that
is already down Moving the modulation
wheel Pushing the volume pedal Moving the data
slider Drawing a pan graph Depressing the sustain
pedal Moving the pitch wheel Pressing the preset
button
Note on message
Note on with velocity 0
A series of aftertouch messages
series of control change messages (1)
series of control change messages (7)
series of control change messages (6)
series of control change messages (10)
Control change - 127 for cont. 64
A series of pitch bend messages, LSB MSB
Program change message
11
Quiz 2
IN
OUT
IN
THRU
OUT
IN
THRU
OUT
12
Quiz 2
IN
OUT
IN
THRU
OUT
IN
THRU
OUT
13
MIDI Driver

• Program that handles MIDI input and output
  function. Owns MIDI I/O ports
• Shared resource that handles connections between
  different programs

14
Musical Possibilities of MIDI

• Separates input device from sound generator
• Separation extends control possibilities
• Software for interaction, algorithmic comp, patch
  editing, and sequencing
• Generic (device-independent) software
• Targeted music software (editor/librarians)
• Reinterpretaton by other devices
• Exchange of data between devices made by
  different manufacturers.