jsm Manual & Documentation

Table Of Contents

MIDIInput

The MIDIInput objects represents a handle to a MIDI input port. Its constructor function accepts a port name as argument.

Applications are notified by incoming messages by the way of events that are delivered to callbacks, using the standard node event handling idiom.

All event handlers are called with the message timestamp as last argument. The message timestamp indicates the point in time when the message was received, measured in milliseconds since the start of the program.

MIDIInput(portName)

Return a MIDIInput object opened to the port with the given portName. portName can be specified as undefined. If so, the port named by the MIDI_INPUT environment variable, or, if that variable is not set, the first MIDI input port available in the system will be opened.

Higher-level events

Event: 'nrpn7'

Event: 'nrpn14'

function (parameterNumber, value, channel, time) { }

Emitted when an NRPN control change has been received. NRPNs are a sort of extended parameters that allow for a larger number of parameters with a wider value range to be submitted. The parameter number is represented by 14 bits sent in two controlChange message for controller 0x63 (MSB) and 0x62 (LSB), the value is either 7 bits sent as controlChange for controller 0x06, or 14 bits sent in two controlChange messages for controller 0x06 (MSB) and 0x26 (LSB). To change the value of an NRPN controller, the sender first sends the parameter number as two controlChange messages for controller 0x63 (MSB) and 0x62 (LSB) followed by the value, either as one message for controller 0x06 or as two messages for controller 0x06 (MSB) and controller 0x26.

When the NRPN controller number has been selected, the sender can also send incremental changes using the controller number 0x60 (increment) or 0x61 (decrement).

The sender does not need to re-select the NRPN controller for each value change. Rather, the NRPN controller is kept selected until overwritten. For NRPN controllers in 14 bit mode, it is possible to send only the LSB after the controller number and the MSB have been sent.

The 'nrpn7' and 'nrpn14' events are emitted to the application whenever a new value has been completely received, either through an incremental or an absolute change message.

Standard MIDI message events

Applications can listen for any of the standard MIDI messages as listed below. Event handlers are called with the message argument(s) parsed as integer values.

Event: 'noteOn'

function (pitch, velocity, channel, time) { }

Event: 'noteOff'

function (pitch, velocity, channel, time) { }

Event: 'polyphonicKeyPressure'

function (pitch, velocity, channel, time) { }

Event: 'controlChange'

function (controllerNumber, controllerValue, channel, time) { }

Event: 'programChange'

function (programNumber, channel, time) { }

Event: 'channelPressure'

function (pressureValue, channel, time) { }

Event: 'pitchWheelChange'

function (valueLsb, valueMsb, channel, time) { }

System Common Messages

Event: 'sysex'

function (message, time) { }

Emitted when a system exclusive message has been received. The message is passed as an array of numbers, including the 0xf0 and 0xf7 message delimiters.

Event: 'midiTimeCode'

function (argument, time) { }

Event: 'songPositionPointer'

function (positionLsb, positionMsb, time) { }

Event: 'songSelect'

function (songNumber, time) { }

Event: 'tuneRequest'

function (time) { }

System Real-Time Messages

Event: 'timingClock'

function (time) { }

Event: 'tick'

function (time) { }

Event: 'start'

function (time) { }

Event: 'stop'

function (time) { }

Event: 'continue'

function (time) { }

Event: 'activeSensing'

function (time) { }

Event: 'reset'

function (time) { }

MIDIInput.portName

Returns the port name that this MIDIInput object has been opened on.

MIDIOutput.channels(argument)

Establish the channel mask for received messages. By default, messages for all channels are received.

The argument may be either a single channel number or an array of channel numbers to listen to. Channel numbers are one-based. Channel number zero indicates that messages for all channels should be listened for.