Art-Net Plugin

Overview

The Art-Net plugin implements the Art-Net protocol for transmitting and receiving DMX512 data over Ethernet networks. Art-Net is an industry-standard protocol widely supported by lighting consoles, controllers, and fixtures.

The plugin name as reported by QLC+ is “Art-Net”

Capabilities

The Art-Net plugin supports:

Output - Send DMX data over network
Input - Receive DMX data from network nodes
Infinite - Unlimited universes
RDM - Remote Device Management (experimental)

Protocol Specifications

Protocol: Art-Net (UDP-based)
Port: 6454 (UDP)
Universe Range: 0-32767 (per Art-Net spec)
Channels per Universe: 512

#define ARTNET_PORT 6454

Network Interface Structure

The plugin creates a controller for each network interface:

typedef struct _aio
{
    QNetworkInterface iface;          // Network interface
    QNetworkAddressEntry address;     // IP address configuration
    ArtNetController* controller;     // Controller instance
} ArtNetIO;

Configuration

Network Interface Detection

The plugin automatically detects all available network interfaces at startup. You can configure the interface wait time:

#define SETTINGS_IFACE_WAIT_TIME "ArtNetPlugin/ifacewait"

Why Interface Wait Time?

Some systems need time for network interfaces to become fully ready after QLC+ starts. The default wait time ensures interfaces are properly initialized before the plugin attempts to bind to them.

Custom Parameters

Art-Net supports several custom parameters:

#define ARTNET_INPUTUNI "inputUni"       // Input universe number
#define ARTNET_OUTPUTIP "outputIP"       // Output IP address  
#define ARTNET_OUTPUTUNI "outputUni"     // Output universe number
#define ARTNET_TRANSMITMODE "transmitMode" // Transmission mode

Setting Parameters

void setParameter(quint32 universe, quint32 line, 
                  Capability type, QString name, QVariant value);

Example parameters:

outputIP - Target IP address (broadcast or unicast)
outputUni - Art-Net universe number (0-32767)
inputUni - Universe number to listen for
transmitMode - Standard, Full, or Partial transmission

Output Configuration

Opening an Output

bool openOutput(quint32 output, quint32 universe);

When you open an output line:

The plugin creates or reuses an Art-Net controller for the network interface
Configures the output universe mapping
Sets up UDP socket for transmission

Output Modes

The Art-Net controller supports three transmission modes:

enum TransmissionMode { 
    Standard,  // Send only changed channels
    Full,      // Always send full 512-channel universe
    Partial    // Send only up to highest changed channel
};

Standard Mode
Full Mode
Partial Mode

Sends DMX data only when channel values change. Most efficient for typical use.Best for: Normal operation, conserving bandwidth

Sending Data

void writeUniverse(quint32 universe, quint32 output, 
                   const QByteArray& data, bool dataChanged);

The plugin:

Retrieves the Art-Net controller for the output line
Calls sendDmx() with universe and data
Controller packetizes and transmits via UDP

Broadcast vs Unicast

You can configure the output IP address: Broadcast (default):

2.255.255.255  // Subnet broadcast
255.255.255.255 // Limited broadcast

Unicast:

192.168.1.100  // Specific device IP

Unicast is more efficient and reduces network traffic. Use it when you know the exact IP addresses of your Art-Net nodes.

Input Configuration

Opening an Input

bool openInput(quint32 input, quint32 universe);

The plugin listens for Art-Net packets on UDP port 6454.

Receiving Data

When Art-Net packets arrive:

The plugin’s UDP socket receives the datagram
handlePacket() processes the Art-Net packet
Controller emits valueChanged() signal for each changed channel
QLC+ engine receives and processes the input

signal void valueChanged(quint32 universe, quint32 input, 
                        quint32 channel, uchar value);

Input Universe Mapping

Set the Art-Net universe to listen for:

setParameter(universe, line, Input, "inputUni", artnetUniverseNumber);

Universe Mapping

Art-Net uses 15-bit universe addressing (0-32767), while QLC+ has its own universe indexing:

typedef struct _uinfo
{
    int type;                     // Input, Output, or both
    ushort inputUniverse;         // Art-Net universe for input
    QHostAddress outputAddress;   // Destination IP for output  
    ushort outputUniverse;        // Art-Net universe for output
    int outputTransmissionMode;   // Standard/Full/Partial
} UniverseInfo;

Example Mapping

QLC+ Universe	Art-Net Universe	Direction	IP Address
1	0	Output	2.255.255.255
2	1	Output	192.168.1.100
3	0	Input	(listening)
4	10	Both	192.168.1.101

RDM Support

The plugin has experimental RDM over Art-Net support:

bool sendRDMCommand(quint32 universe, quint32 line, 
                    uchar command, QVariantList params);

RDM over Art-Net is experimental and may not work with all devices. Most Art-Net nodes do not support RDM.

Network Configuration Best Practices

Dedicated Network

Use a dedicated network interface

Dedicate one NIC for Art-Net to avoid conflicts with general network traffic

Use appropriate subnet

Common Art-Net subnet: 2.x.x.x or 10.x.x.x

Configure static IPs

Avoid DHCP for Art-Net devices to ensure consistent addressing

Disable firewall for Art-Net port

Ensure UDP port 6454 is open for both input and output

IP Address Configuration

Recommended ranges:

0.0.0/8     // Traditional Art-Net range
0.0.0/8    // Private network range
168.0.0/16 // Private network range

The 2.x.x.x range is historically used for Art-Net, but any private IP range works fine.

Subnet Broadcast Addresses

For a 255.255.255.0 subnet mask:

0.0.255      // 2.0.0.x subnet broadcast
0.1.255     // 10.0.1.x subnet broadcast  
168.1.255  // 192.168.1.x subnet broadcast

Performance Optimization

Reduce Broadcast Traffic

Use unicast when possible instead of broadcast
Use Standard or Partial transmission modes
Patch only required universes

Network Switch Configuration

Use switches with IGMP snooping for multicast
Ensure switches support sufficient bandwidth (Gigabit recommended)
Use QoS to prioritize Art-Net traffic

Multiple Network Interfaces

If you have multiple NICs:

QLC+ creates a separate controller for each interface
Each controller can handle multiple universes
Distribute universes across interfaces for load balancing

Troubleshooting

No Output

Check network connection

Verify the network interface is up and configured with an IP address

Verify IP address and subnet

Ensure QLC+ and Art-Net devices are on the same subnet (or properly routed)

Check firewall settings

UDP port 6454 must be open for both incoming and outgoing traffic

Verify universe mapping

Double-check the Art-Net universe numbers match between QLC+ and receiving devices

No Input

Ensure input line is opened and patched
Verify the Art-Net node is sending to the correct IP address
Check that input universe numbers match
Use Wireshark to verify Art-Net packets are arriving

Performance Issues

Switch to unicast addressing
Use Standard transmission mode
Reduce number of patched universes
Check for network congestion
Verify switch/router performance

Firewall Configuration

Linux (iptables):

sudo iptables -A INPUT -p udp --dport 6454 -j ACCEPT
sudo iptables -A OUTPUT -p udp --sport 6454 -j ACCEPT

Linux (firewalld):

sudo firewall-cmd --permanent --add-port=6454/udp
sudo firewall-cmd --reload

Windows:

New-NetFirewallRule -DisplayName "Art-Net" -Direction Inbound -Protocol UDP -LocalPort 6454 -Action Allow

Protocol Details

For full Art-Net protocol specifications, see:

Artistic Licence Art-Net Documentation

E1.31 (sACN)

Alternative streaming ACN protocol

OSC

Open Sound Control protocol

Plugin Overview

Learn about the plugin architecture

Supported Protocols

Hardware Support

​Overview

​Capabilities

​Protocol Specifications

​Network Interface Structure

​Configuration

​Network Interface Detection

​Custom Parameters

​Setting Parameters

​Output Configuration

​Opening an Output

​Output Modes

​Sending Data

​Broadcast vs Unicast

​Input Configuration

​Opening an Input

​Receiving Data

​Input Universe Mapping

​Universe Mapping

​Example Mapping

​RDM Support

​Network Configuration Best Practices

​Dedicated Network

​IP Address Configuration

​Subnet Broadcast Addresses

​Performance Optimization

​Reduce Broadcast Traffic

​Network Switch Configuration

​Multiple Network Interfaces

​Troubleshooting

​No Output

​No Input

​Performance Issues

​Firewall Configuration

​Protocol Details

​Related Pages

E1.31 (sACN)

OSC

Plugin Overview

Build docs developers (and LLMs) love

Overview

Capabilities

Protocol Specifications

Network Interface Structure

Configuration

Network Interface Detection

Custom Parameters

Setting Parameters

Output Configuration

Opening an Output

Output Modes

Sending Data

Broadcast vs Unicast

Input Configuration

Opening an Input

Receiving Data

Input Universe Mapping

Universe Mapping

Example Mapping

RDM Support

Network Configuration Best Practices

Dedicated Network

IP Address Configuration

Subnet Broadcast Addresses

Performance Optimization

Reduce Broadcast Traffic

Network Switch Configuration

Multiple Network Interfaces

Troubleshooting

No Output

No Input

Performance Issues

Firewall Configuration

Protocol Details

Related Pages