vuo.midi

These nodes are for sending and receiving MIDI notes and other MIDI messages (MIDI events).

A MIDI input device (such as a keyboard, controller, or sequencer) can send MIDI messages to the Receive MIDI Events node, allowing the device to control the composition.

A MIDI output device (such as a synthesizer, sequencer, or stage lighting equipment) can receive MIDI messages from the Send MIDI Events node, allowing the composition to control the device.

Each MIDI device has a unique ID, which is assigned by the operating system. If all devices were plugged in after the computer started up, then ID 0 is usually the first device plugged in, ID 1 is usually the second device plugged in, etc.

Each MIDI device has a name, which is not necessarily unique. On Mac OS X, you can look up a device’s name in the Audio MIDI Setup application.

A MIDI note message often represents a musical note. It includes:

• A note number, ranging from 0 to 127. This often represents the pitch of the note, with Middle C (C4) at 60.
• A velocity, ranging from 0 to 127. This often represents the force with which the note is played.
• Whether this is a Note On or a Note Off message. A Note On message represents that a note is depressed (started). A Note Off message represents that a note is released (ended).

A MIDI controller message often represents a musical effect (volume, panning, filter cutoff, sustain, etc.). A controller message can be sent by a control on a MIDI device (knob, fader, pedal, etc.). It includes:

• A controller number, ranging from 0 to 127. This often represents the type of effect.
• A controller value, ranging from 0 to 127. This often represents amount of the effect. Some effects use the whole range of values, while others are either on (0-63) or off (64-127).

A MIDI pitch bend message often represents a change in the relative pitch of all notes on a certain MIDI channel. Its value ranges from 0 to 16,383, with 8,192 being the center point (no pitch change). The pitch bend range varies per device and configuration, but often the full range covers a whole tone (value 0 is 2 semitones down, value 16,383 is 2 semitones up).

MIDI note, controller, and pitch bend messages also include:

• A channel, ranging from 1 to 16. Each channel has its own stream of MIDI notes and controller values. A channel often represents one musical instrument.

You can send MIDI messages between two Vuo compositions, one with a Send MIDI Event node and the other with a Receive MIDI Events node. For this to work, you need to set up a MIDI device that supports both input and output. The compositions will communicate through this device. On Mac OS X, you can set up the device like this: open the Audio MIDI Setup application and go to the MIDI window, double-click on the IAC driver, and check the box for “Device is online”. Then run the compositions.

Example compositions:

• Animate For Midi Note: Flashes the small square whenever any MIDI note is received, and plays a special animation when the C#5 (just above middle C) is received.
• Receive Midi Notes: Receives MIDI notes and pitch bend messages from MIDI Channel 1 of the default MIDI device and plays them aloud.
• Send Midi Notes: Sends MIDI notes, with pitches randomly generated from simplex noise, to a MIDI device. Requires a MIDI device to play sound.
• Show Piano Roll: Receives MIDI notes from a MIDI device and displays them like a player-piano-style piano roll.

Nodes:

• Filter Controller (vuo.midi.filter.controller): Only lets a MIDI controller pass through if its channel and controller number match.
• Filter Note (vuo.midi.filter.note): Only lets a MIDI note pass through if its channel and note number match.
• Filter Pitch Bend (vuo.midi.filter.pitchBend): Only lets a MIDI pitch bend pass through if its channel matches.
• Get Controller Values (vuo.midi.get.controller): Gives the components of a MIDI controller message.
• Get MIDI Input Values (vuo.midi.get.input): Gives information about a MIDI input device.
• Get Note Values (vuo.midi.get.note): Gives the components of a MIDI note message.
• Get MIDI Output Values (vuo.midi.get.output): Gives information about a MIDI output device.
• Get Pitch Bend Values (vuo.midi.get.pitchBend): Gives the components of a MIDI pitch bend message.
• List MIDI Devices (vuo.midi.listDevices): Gives a list of all available MIDI input and output devices.
• Make Controller (vuo.midi.make.controller): Creates a MIDI controller message that can be sent to a MIDI device.
• Make MIDI Input from ID (vuo.midi.make.input.id): Finds a MIDI input device that is connected to the computer running the composition.
• Make MIDI Input from Name (vuo.midi.make.input.name): Finds a MIDI input device that is connected to the computer running the composition.
• Make Note (vuo.midi.make.note): Creates a MIDI note message that can be sent to a MIDI device.
• Make MIDI Output from ID (vuo.midi.make.output.id): Finds a MIDI output device that is connected to the computer running the composition.
• Make MIDI Output from Name (vuo.midi.make.output.name): Finds a MIDI output device that is connected to the computer running the composition.
• Make Pitch Bend (vuo.midi.make.pitchBend): Creates a MIDI pitch bend message that can be sent to a MIDI device.
• Convert Note to Frequency (vuo.midi.note.frequency): Outputs the frequency associated with a MIDI note number.
• Receive MIDI Events (vuo.midi.receive): Fires events when MIDI messages are received from an input device.
• Send MIDI Event (vuo.midi.send): Sends a MIDI message to an output device.
• Track Single Note (vuo.midi.track.note.mono): Chooses a single MIDI note of the notes that are currently on, based on a note priority rule.
• Track Notes (vuo.midi.track.note.poly): Outputs a list of the MIDI notes that are currently on.