---
title: MIDI, OSC & MQTT
layout: ../../layouts/MainLayout.astro
---

import { MiniRepl } from '../../docs/MiniRepl';
import { JsDoc } from '../../docs/JsDoc';

# MIDI, OSC and MQTT

Normally, Strudel is used to pattern sound, using its own '[web audio](https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_API)'-based synthesiser called [SuperDough](https://codeberg.org/uzu/strudel/src/branch/main/packages/superdough).

It is also possible to pattern other things with Strudel, such as software and hardware synthesisers with MIDI, other software using Open Sound Control/OSC (including the [SuperDirt](https://github.com/musikinformatik/SuperDirt/) synthesiser commonly used with Strudel's sibling [TidalCycles](https://tidalcycles.org/)), or the MQTT 'internet of things' protocol.

# MIDI

Strudel supports MIDI without any additional software (thanks to [webmidi](https://npmjs.com/package/webmidi)), just by adding methods to your pattern:

## midin(inputName?)

<JsDoc client:idle name="midin" h={0} />

## midikeys(inputName?)

<JsDoc client:idle name="midikeys" h={0} />

## midi(outputName?,options?)

Either connect a midi device or use the IAC Driver (Mac) or Midi Through Port (Linux) for internal midi messages.
If no outputName is given, it uses the first midi output it finds.

<MiniRepl
  client:idle
  tune={`
$: chord("<C^7 A7 Dm7 G7>").voicing().midi('IAC Driver')
`}
/>

In the console, you will see a log of the available MIDI devices as soon as you run the code,
e.g.

```
 `Midi connected! Using "Midi Through Port-0".`
```

The `.midi()` function accepts an options object with the following properties:

<MiniRepl
  client:idle
  tune={`$: note("d e c a f").midi('IAC Driver', { isController: true, midimap: 'default'})
`}
/>

<details>
<summary>Available Options</summary>

| Option       | Type          | Default   | Description                                                            |
| ------------ | ------------- | --------- | ---------------------------------------------------------------------- |
| isController | boolean       | false     | When true, disables sending note messages. Useful for MIDI controllers |
| latencyMs    | number        | 34        | Latency in milliseconds to align MIDI with audio engine                |
| noteOffsetMs | number        | 10        | Offset in milliseconds for note-off messages to prevent glitching      |
| midichannel  | number        | 1         | Default MIDI channel (1-16)                                            |
| velocity     | number        | 0.9       | Default note velocity (0-1)                                            |
| gain         | number        | 1         | Default gain multiplier for velocity (0-1)                             |
| midimap      | string        | 'default' | Name of MIDI mapping to use for control changes                        |
| midiport     | string/number | -         | MIDI device name or index                                              |

</details>

### midiport(outputName)

Selects the MIDI output device to use, pattern can be used to switch between devices.

```javascript
$: midiport('IAC Driver');
$: note('c a f e').midiport('<0 1 2 3>').midi();
```

<JsDoc client:idle name="midiport" h={0} />

## midichan(number)

Selects the MIDI channel to use. If not used, `.midi` will use channel 1 by default.

## midicmd(command)

`midicmd` sends MIDI system real-time messages to control timing and transport on MIDI devices.

It supports the following commands:

- `clock`/`midiClock` - Sends MIDI timing clock messages
- `start` - Sends MIDI start message
- `stop` - Sends MIDI stop message
- `continue` - Sends MIDI continue message

// You can control the clock with a pattern and ensure it starts in sync when the repl begins.
// Note: It might act unexpectedly if MIDI isn't set up initially.

<MiniRepl
  client:idle
  tune={`$:stack(
  midicmd("clock*48,<start stop>/2").midi('IAC Driver')
)`}
/>

## control, ccn && ccv

- `control` sends MIDI control change messages to your MIDI device.
- `ccn` sets the cc number. Depends on your synths midi mapping
- `ccv` sets the cc value. normalized from 0 to 1.

<MiniRepl client:idle tune={`note("c a f e").control([74, sine.slow(4)]).midi()`} />

<MiniRepl client:idle tune={`note("c a f e").ccn(74).ccv(sine.slow(4)).midi()`} />

In the above snippet, `ccn` is set to 74, which is the filter cutoff for many synths. `ccv` is controlled by a saw pattern.
Having everything in one pattern, the `ccv` pattern will be aligned to the note pattern, because the structure comes from the left by default.
But you can also control cc messages separately like this:

<MiniRepl
  client:idle
  tune={`$: note("c a f e").midi()
$: ccv(sine.segment(16).slow(4)).ccn(74).midi()`}
/>

Instead of setting `ccn` and `ccv` directly, you can also create mappings with `midimaps`:

## midimaps

<JsDoc client:idle name="midimaps" h={0} />

## defaultmidimap

<JsDoc client:idle name="defaultmidimap" h={0} />

## progNum (Program Change)

`progNum` sends MIDI program change messages to switch between different presets/patches on your MIDI device.
Program change values should be numbers between 0 and 127.

<MiniRepl client:idle tune={`// Switch between programs 0 and 1 every cycle
progNum("<0 1>").midi()

// Play notes while changing programs
note("c3 e3 g3").progNum("<0 1 2>").midi()`} />

Program change messages are useful for switching between different instrument sounds or presets during a performance.
The exact sound that each program number maps to depends on your MIDI device's configuration.

## sysex, sysexid && sysexdata (System Exclusive Message)

`sysex` sends MIDI System Exclusive (SysEx) messages to your MIDI device.
ysEx messages are device-specific commands that allow deeper control over synthesizer parameters.
The value should be an array of numbers between 0-255 representing the SysEx data bytes.

<MiniRepl
  client:idle
  tune={`// Send a simple SysEx message
let id = 0x43; //Yamaha
//let id = "0x00:0x20:0x32"; //Behringer ID can be an array of numbers
let data = "0x79:0x09:0x11:0x0A:0x00:0x00"; // Set NSX-39 voice to say "Aa"
$: note("c a f e").sysex(id, data).midi();
$: note("c a f e").sysexid(id).sysexdata(data).midi();`}
/>

The exact format of SysEx messages depends on your MIDI device's specification.
Consult your device's MIDI implementation guide for details on supported SysEx messages.

## midibend && miditouch

`midibend` sets MIDI pitch bend (-1 - 1)
`miditouch` sets MIDI key after touch (0-1)

<MiniRepl client:idle tune={`note("c a f e").midibend(sine.slow(4).range(-0.4,0.4)).midi()`} />

<MiniRepl client:idle tune={`note("c a f e").miditouch(sine.slow(4).range(0,1)).midi()`} />

# OSC/SuperDirt/StrudelDirt

In TidalCycles, sound is usually generated using [SuperDirt](https://github.com/musikinformatik/SuperDirt/), which runs inside SuperCollider. Strudel also supports using SuperDirt, although it requires installing some additional software.

There is also [StrudelDirt](https://github.com/daslyfe/StrudelDirt) which is SuperDirt with some optimisations for working with Strudel. (A longer term aim is to merge these optimisations back into mainline SuperDirt)

## Prequisites

To get SuperDirt to work with Strudel, you need to

1. install SuperCollider + sc3 plugins, see [Tidal Docs](https://tidalcycles.org/docs/) (Install Tidal) for more info.
2. install SuperDirt, or the [StrudelDirt](https://github.com/daslyfe/StrudelDirt) fork which is optimised for use with Strudel
3. install [node.js](https://nodejs.org/en/)
4. download [Strudel Repo](https://codeberg.org/uzu/strudel/) (or git clone, if you have git installed)
5. run `pnpm i` in the strudel directory
6. run `pnpm run osc` to start the osc server, which forwards OSC messages from Strudel REPL to SuperCollider

Now you're all set!

## Usage

1. Start SuperCollider, either using SuperCollider IDE or by running `sclang` in a terminal
2. Open the [Strudel REPL](https://strudel.cc/#cygiYmQgc2QiKS5vc2MoKQ%3D%3D)

...or test it here:

<MiniRepl client:only="react" tune={`s("bd sd").osc()`} />

If you now hear sound, congratulations! If not, you can get help on the [#strudel channel in the TidalCycles discord](https://discord.com/invite/HGEdXmRkzT).

Note: if you have the 'Audio Engine Target' in settings set to 'OSC', you do not need to add .osc() to the end of your pattern.

### Pattern.osc

<JsDoc client:idle name="Pattern.osc" h={0} />

## SuperDirt Params

Please refer to [Tidal Docs](https://tidalcycles.org/) for more info.

<br />

But can we use Strudel [offline](/learn/pwa)?

# MQTT

MQTT is a lightweight network protocol, designed for 'internet of things' devices. For use with strudel, you will
need access to an MQTT server known as a 'broker' configured to accept secure 'websocket' connections. You could
run one yourself (e.g. by running [mosquitto](https://mosquitto.org/)), although getting an SSL certificate that
your web browser will trust might be a bit tricky for those without systems administration experience.
Alternatively, you can use [a public broker](https://www.hivemq.com/mqtt/public-mqtt-broker/).

Strudel does not yet support receiving messages over MQTT, only sending them.

## Usage

The following example shows how to send a pattern to an MQTT broker:

<MiniRepl
  client:only="react"
  tune={`"hello world"
    .mqtt(undefined, // username (undefined for open/public servers)
          undefined, // password
          '/strudel-pattern', // mqtt 'topic'
          'wss://mqtt.eclipseprojects.io:443/mqtt', // MQTT server address
          'mystrudel', // MQTT client id - randomly generated if not supplied
          0 // latency / delay before sending messages (0 = no delay)
         )`}

/>

Other software can then receive the messages. For example using the [mosquitto](https://mosquitto.org/) commandline client tools:

```

> mosquitto_sub -h mqtt.eclipseprojects.io -p 1883 -t "/strudel-pattern"
> hello
> world
> hello
> world
> ...

```

Control patterns will be encoded as JSON, for example:

<MiniRepl
  client:only="react"
  tune={`sound("sax(3,8)").speed("2 3")
  .mqtt(undefined, // username (undefined for open/public servers)
        undefined, // password
        '/strudel-pattern', // mqtt 'topic'
        'wss://mqtt.eclipseprojects.io:443/mqtt', // MQTT server address
        'mystrudel', // MQTT client id - randomly generated if not supplied
        0 // latency / delay before sending messages (0 = no delay)
       )`}
/>

Will send messages like the following:

```

{"s":"sax","speed":2}
{"s":"sax","speed":2}
{"s":"sax","speed":3}
{"s":"sax","speed":2}
...

```

Libraries for receiving MQTT are available for many programming languages.

```

```
