Skip to main content

​
Overview

QLC+ uses a flexible plugin architecture to support various input/output protocols and hardware devices. Each plugin implements the QLCIOPlugin interface, providing a standardized way to communicate with different lighting control systems.

​
Plugin Interface

All plugins inherit from the QLCIOPlugin base class, which defines the core interface for input/output operations: 
class QLCIOPlugin : public QObject
{
    virtual void init() = 0;
    virtual QString name() const = 0;
    virtual int capabilities() const = 0;
    virtual QString pluginInfo() const = 0;
};

​
Plugin Capabilities

Plugins can support different capabilities through a bitmask system:
  • Output - Send DMX/control data to devices
  • Input - Receive data from controllers
  • Feedback - Send visual feedback to input devices
  • Infinite - Support unlimited universes (network protocols)
  • RDM - Remote Device Management support
  • Beats - Beat detection for audio synchronization

​
Available Plugins

​
Network Protocols

Art-Net

Industry-standard DMX over Ethernet protocol using UDP port 6454

E1.31 (sACN)

ANSI E1.31 streaming ACN protocol, UDP port 5568

OSC

Open Sound Control for flexible, bidirectional communication

OS2L

Open Show 2 Light protocol for third-party integration

​
USB Hardware

DMX USB

USB-to-DMX interfaces from various manufacturers

ENTTEC

ENTTEC DMX USB Pro, Pro Mk2, and Open DMX USB

DMXKing

DMXKing ultraDMX Pro and other DMXKing devices

​
Control Protocols

MIDI

MIDI input/output for hardware controllers and feedback

HID

Human Interface Devices (joysticks, gamepads, etc.)

​
Integration

OLA

Open Lighting Architecture integration for advanced protocol support

​
Plugin Universe Mapping

Each plugin maintains a mapping between QLC+ universes and plugin-specific lines: 
typedef struct
{
    quint32 inputLine;              // Plugin input line (UINT_MAX if not patched)
    QMap<QString, QVariant> inputParameters;  // Custom input parameters
    quint32 outputLine;             // Plugin output line (UINT_MAX if not patched)
    QMap<QString, QVariant> outputParameters; // Custom output parameters
} PluginUniverseDescriptor;
The default maximum number of universes is 4, but network-based plugins can support unlimited universes through the Infinite capability.

​
Data Flow

​
Output Data Flow

  1. QLC+ engine generates DMX data (0-512 channels)
  2. Engine calls writeUniverse() on the plugin
  3. Plugin processes and transmits data to hardware/network
virtual void writeUniverse(quint32 universe, quint32 output, 
                          const QByteArray& data, bool dataChanged);

​
Input Data Flow

  1. Plugin receives data from hardware/network
  2. Plugin emits valueChanged() signal
  3. QLC+ engine processes incoming values
signal void valueChanged(quint32 universe, quint32 input, 
                        quint32 channel, uchar value, const QString& key);

​
Configuration

Plugins can provide custom configuration dialogs: 
virtual void configure();           // Open configuration dialog
virtual bool canConfigure() const;  // Check if configurable

​
Custom Parameters

Plugins support custom parameters for fine-tuning behavior: 
virtual void setParameter(quint32 universe, quint32 line, 
                         Capability type, QString name, QVariant value);
virtual void unSetParameter(quint32 universe, quint32 line, 
                           Capability type, QString name);

​
RDM Support

Some plugins support Remote Device Management (RDM) for bi-directional device communication: 
virtual bool sendRDMCommand(quint32 universe, quint32 line, 
                           uchar command, QVariantList params);
RDM enables:
  • Device discovery
  • Parameter reading/writing
  • Status monitoring
  • Remote configuration
RDM is currently only supported by ENTTEC DMX USB Pro and DMXKing devices through the DMX USB plugin.

​
Hotplug Support

Modern plugins support USB hotplug detection, automatically detecting when devices are connected or disconnected: 
public slots:
    void slotDeviceAdded(uint vid, uint pid);
    void slotDeviceRemoved(uint vid, uint pid);

​
Next Steps

Network Setup

Configure Art-Net or E1.31 for network-based control

USB Hardware

Set up USB-to-DMX interfaces

MIDI Control

Connect MIDI controllers for hands-on control

OLA Integration

Use OLA for advanced protocol support

Build docs developers (and LLMs) love

Get started for freeTalk to us