WEBrtpMIDI

This repo is a small project aiming to replicate the DMX console Eurolight LC2412 in the WEB browser to be used remotely on any device. It can also be used with any other MIDI device.

basically, WEBrtpMIDI transmits every MIDI note it receives to rtpMIDI sessions connected. It can also receive MIDI notes on a rtpMIDI session and transmit them back to every connected rtpMIDI session. It also serves a web page on which virtual faders are present that also send MIDI notes to rtpMIDI sessions.

As it is, it is not very functional and was created to serve my own needs but I plan to make improvements in order to make it more customizable (see section below for planned features). It has only been tested on Linux, but most of the features should work on Windows too. Also, you don't need a high-end computer, as I run it on a 1GHz single core and 1 Go of RAM PC (it uses only ~20Mo).

Features

• Possibility to use several MIDI devices at the same time, and to enable and disable any of them at any time
• Connection of several rtpMIDI clients
• Possibility to name the faders (the names are automatically senton all connected web clients)
• The values inserted by a web client are instantly sent to other WEB client (including fader names)
• Possibility to change the MIDI channel on which the WEB client is bound to
• Possibility to shut down the system via the WEB client

Future development

Here are some improvements I want to incorporate to make this piece of software more useful.

• Possibility to save (currently, as soon as the software is turned off, everything is lost)
• Customizable layout (currently, only the LC2412 layout is available, and is hardcoded) with the possibility to save and load layouts. Each layout would consist of faders, textareas, buttons, positionners, etc. Each one of them would have assignable MIDI commands.
• Add system information (such as CPU load, CPU temperature, etc)
• Make the design more responsive
• Make the midi library optional because it needs system packages that are sometimes undesirable.
• Add a real config file

Installation

This tutorial is for Linux. The project runs on nodejs and currently needs four npm packages :

express
socket.io
rtpmidi
midi

The midi package needs alsa and a few system packages to work correctly. We will assume in this tutorial that you want to run this software on a user called webmidi.

Let's start by installing system packages necessary to install and run the midi package :

sudo apt-get install alsa-utils libasound2-dev make g++ git

Then we add the user and right away add it to the audio group to access MIDI devices :

sudo adduser webmidi
sudo adduser webmidi audio

You can now login as user webmidi. Let's now install nodejs. We are going to use the version manager nvm for that purpose.

wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.1/install.sh | bash
export NVM_DIR="$([ -z "${XDG_CONFIG_HOME-}" ] && printf %s "${HOME}/.nvm" || printf %s "${XDG_CONFIG_HOME}/nvm")"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"

I think it is fine to install any recent version of nodejs, but WEBrtpMIDI has only been tested on version 8.16.0 (because my production PC that runs it is very resource limited so I picked a version that is available precompiled).

node install

or

node install 8.16.0

We are now going to install the npm packages dependencies.

npm install express
npm install socket.io
npm install rtpmidi
npm install midi

Let's now download WEBrtpMIDI.

git clone https://github.com/FlorianFun/WEBrtpMIDI

It will create a folder called WEBrtpMIDI, we change directory to it :

cd WEBrtpMIDI

By default, the WEB server start on port 3000. It is possible to change it by editing Main.js.

nano Main.js

The line to edit is the following :

const port = 3000;

On Linux, you need to allow a non root user to use port under 1023 or the application will fail to launch. You can do this with this command (the path has to be edited to the real node installation path. Also, note that this command allows the use of every ports under 1023, there are other ways to achieve this) :

sudo setcap CAP_NET_BIND_SERVICE=+eip /home/webmidi/.nvm/versions/node/v8.16.0/bin/node

Now we want to allow the user to shutdown the computer (this is not mandatory, but if you want to use this feature, you need to do this). You can also change the command executed in the code (look for the word shutdown in Main.js). One way to allow the user is to use sudo. There are several other ways so feel free to use whatever method you prefer.

sudo nano /etc/sudoers

Add the following line :

webmidi ALL=NOPASSWD: /sbin/shutdown

You can now launch the application.

node Main.js