class:: MIDIOut
summary:: send MIDI messages
related:: Classes/MIDIClient, Classes/MIDIIn, Guides/MIDI, Guides/UsingMIDI
categories:: External Control>MIDI

description::
a MIDIOut is bound to a specific link::Classes/MIDIEndPoint:: as defined by the operating system.

Linux users, or any users who require cross-platform compatibility with Linux, should read link::#Linux specific: Connecting and disconnecting ports:: carefully.

ClassMethods::

private::connectByUID, disconnectByUID

method::new

Create a new MIDIOut instance. Note that this method is not safe for cross-platform usage with Linux, because the meaning of the teletype::port:: argument is different. See link::#Linux specific: Connecting and disconnecting ports:: for details.

argument::port
definitionList::
## macOS, Windows || The index of the MIDIEndPoint in the code::MIDIClient.destinations:: array.
## Linux || The output port number. teletype::MIDIEndPoint("SuperCollider", "out0"):: is port 0; teletype::"out1":: is port 1. In Linux, this argument has no connection at all to code::MIDIClient.destinations::.
::

argument::uid
definitionList::
## macOS / Windows || uid is optional; if specified, it should be the uid of that port ie. MIDIClient.destinations[port].uid. If you don't provide a uid, the correct uid will be filled in for you (easier).
## Linux || using the uid is optional as described below.
::

method::newByName
Searches for the MIDI output device, by a name found in the code::MIDIClient.destinations:: array. This is safer then depending on the index which will change if your studio setup changes. It is also Linux compatible.
code::
//list connected out ports with names:
MIDIClient.init;
MIDIClient.destinations;
::

method::findPort
Searches for a connected MIDIEndPoint by name.
code::
//list connected out ports with names:
MIDIClient.init;
MIDIClient.destinations;
::

method::connect, disconnect
Linux only. MacOS does not need to connect. On Linux it is an optional feature (see below).

InstanceMethods::
method::sysex
Sends a sysex command represented as an link::Classes/Int8Array:: to the device.

note::
On Windows, the function call must contain a full sysex message. In other words,
it must start with 0xF0 (240 or -16) and end with 0xF7 (247 or -9).
::

argument:: packet
An Int8Array of data bytes to be sent.

private::send, prSysex

method::latency
This sets the latency with which a midi event is sent out. Per default, this is set to 0.2, in order to be equal to the Server.latency.
note::
On Linux, there seems to be an ALSA or kernel bug if the latency is larger than 0, for some Linux kernels. If MIDIOut does not seem to work, set the latency to 0.
::

Examples::

code::
MIDIClient.init;

m = MIDIOut(0);  // Linux users: MIDIOut(0, MIDIClient.destinations[0].uid)
m.noteOn(16, 60, 60);
m.noteOn(16, 61, 60);
m.noteOff(16, 61, 60);
m.allNotesOff(16);


MIDIIn.connect; // 1 port midi interface
MIDIIn.sysex = { arg uid, packet; [uid,packet].postln };
MIDIIn.sysrt = { arg src, chan, val;  [src, chan, val].postln; };
MIDIIn.smpte = { arg src, chan, val;  [src, chan, val].postln; };

m.sysex(Int8Array[0xF0, 0, 0, 27, 11, 0, 0xF7])

m.smpte(24, 16)
m.midiClock
m.start
m.continue
m.stop
::

subsection::Using patterns for sending MIDI events

code::
MIDIClient.init;
m = MIDIOut(0);  // Linux users: MIDIOut(0, MIDIClient.destinations[0].uid)

a = Pbind(\degree, Prand([1, 2, 3, [0, 5]], inf), \bend, Pwhite(0, 76, inf));


// chain a midi event into the pattern and play it (see Pchain)

(a <> (type: \midi, midiout: m)).play;
::

See link::Tutorials/A-Practical-Guide/PG_08_Event_Types_and_Parameters#MIDI output:: for a list of midi commands supported by the 'midi' event type.

subsection::Linux specific: Connecting and disconnecting ports

In Linux, the MIDIOut architecture is different from other operating systems.

In macOS and Windows, a MIDIOut instance is bound to a specific destination MIDI device.

SuperCollider in Linux uses the ALSA MIDI layer. ALSA MIDI applications send messages out through a "virtual output port," which is one of the members of code::MIDIClient.sources::.

code::
MIDIClient.init;
::

teletype::
MIDI Sources:
	MIDIEndPoint("System", "Timer")
	MIDIEndPoint("System", "Announce")
	MIDIEndPoint("Midi Through", "Midi Through Port-0")
	MIDIEndPoint("SuperCollider", "out0")
	MIDIEndPoint("SuperCollider", "out1")
::

At this point, creating code::MIDIOut(0):: tells SuperCollider that this MIDIOut object should direct messages to teletype::MIDIEndPoint("SuperCollider", "out0")::. (It seems strange, if you think of SuperCollider sending messages to this MIDI emphasis::source::. It is more accurate to think of SuperCollider sending messages emphasis::through:: this port. The port is, then, a source for the rest of the system.)

A code::MIDIOut(0):: object, then, will not reach any destinations by default. The user needs to connect destination devices to the virtual source port, using either a graphical tool such as Qjackctl, or by MIDIOut's teletype::connect:: method.

code::
m = MIDIOut(0);  // use virtual source port "out0"
m.connect(1);  // connect to MIDIClient.destinations[1]
::

WARNING:: The teletype::port:: argument to link::Classes/MIDIOut#*new:: has an entirely different meaning in Linux, compared to macOS and Windows. If user code calls this method emphasis::and:: cross-platform compatibility is needed, it is the user's responsibility to handle Linux separately. User code can check the platform using code::thisProcess.platform.name:: (which returns one of code::\osx::, code::\linux:: or code::\windows::). Or, for compatibility, use link::#*newByName:: instead.::

link::Classes/MIDIOut#*new:: optionally takes a second argument, for the uid of the MIDI destination device. This establishes a direct connection to the target, which is not visible in Qjackctl. The teletype::port:: argument is irrelevant in this case; the MIDIOut instance is always one-to-one with the target.

link::Classes/MIDIOut#*newByName:: should create one-to-one MIDIOut connections on all platforms.

strong::Compatibility::
list::
## code::MIDIOut.newByName("device", "port"):: -- Should be compatible on all systems.
## code::MIDIOut(index):: -- macOS, Windows (teletype::index:: is the device's index in code::MIDIClient.destinations::). Note that this usage is emphasis::not:: compatible with Linux! macOS and Windows users should not expect Linux users to be able to run this style of connection.
## code::MIDIOut(0, MIDIClient.destinations[index].uid):: -- Linux only (teletype::index:: is the device's index in code::MIDIClient.destinations::).
::


subsection::macOS specific: Sending MIDI to other applications

Open the Audio MIDI Setup application. Double-click on IAC Driver and check "device is online".

reinitialize:

MIDIClient.init(numIns,numOuts)

The IAC Bus will now appear in MIDIClient.destinations. It will appear first, which means that any code that you have written that addresses the first physical bus as 0 will now have to be changed.

For this reason, it is always safer to find the port by name :
code::
MIDIOut.newByName("RemoteSL IN","Port 1");
::
The IAC Bus will now also appear to other applications.


MIDIMonitor (freeware) can be very useful for troubleshooting:

http://www.snoize.com/MIDIMonitor/

subsection::Sysex example

a machinedrum manual say sysex commands should be formatted like this...
code::
$f0,$00,$20,$3c,$02,$00,command,...,$f7
::

and to set the tempo the machinedrum expects this command...
code::
$61 | Set tempo ID
%0aaaaaaa | Upper bits
%0bbbbbbb | Lower bits
$f7 | SYSEX end
Note: Tempo = %aaaaaaabbbbbbb / 24, max 300 BPM, min 30 BPM
::

so to create and send a valid set tempo sysex command from SuperCollider to this machinedrum do...
code::
MIDIClient.init;
m = MIDIOut(0);  // Linux users: MIDIOut(0, MIDIClient.destinations[0].uid)
m.sysex(Int8Array[0xf0, 0x00, 0x20, 0x3c, 0x02, 0x00, 0x61, 21, 54, 0xf7]);
::

This will set the tempo to 114.23 bpm. One can calculate the upper and lower 7bit values like this...
code::
(
var bpm, val, upper, lower;
bpm = 114.23;
val = (bpm*24).round.asInteger;
upper = val&2r11111110000000>>7;
lower = val&2r00000001111111;
[upper, lower].postln;
)
::
where the resulting 21 and 54 are the same as 2r0010101 and 2r0110110 in binary notation.
