Artnet Device

Artnet is a common implementation of DMX over Ethernet. It is widely used in the lighting industry and is supported by a large variety of devices.

For more information, see Art-Net on Wikipedia.

Pre and Post Amble

To support Artnet devices, it is important to be able to set fixed values in channels that can be positioned before or after the RGB data, for example, to control brightness.

In LedFx, these values can only be static, but the simple implementation of pre-amble and post-amble values supports most simple devices. The pre-amble and post-amble fields can be treated as comma or space-separated values from the uint8 range (0-255).

Common Use Cases

Single Pixel RGB Device with Brightness Before RGB Data:
- Set the pre-amble to 255 for maximum brightness and leave the post-amble empty.
- The resulting channel data sent to the Artnet device universe will be in the format:
```
[255, R, G, B]
```
Single Pixel RGB Device with Brightness After RGB Data:
- Set the post-amble to 255 for maximum brightness and leave the pre-amble empty.
- The resulting channel data sent to the Artnet device universe will be in the format:
```
[R, G, B, 255]
```
Pixel RGB Device with Brightness and Additional Channels:
- Set the pre-amble to 255, 0, 0, 0 for maximum brightness with other channels turned off. Leave the post-amble empty.
- The resulting channel data sent to the Artnet device universe will be in the format:
```
[255, 0, 0, 0, R, G, B]
```

Device Repeat

It is common to have multiple Artnet devices on one universe with the same channel format. Each device requires its own pre- and post-amble. The device_repeat field can be set to the number of pixels assigned to each device. LedFx will then consume that number of pixels serially, wrapping each set with pre- and post-amble sequences until all pixels are used. Any leftover pixels are ignored.

If device_repeat is set to 0, all pixels are sent to the first device, wrapped with the pre- and post-amble sequences.

Examples

Pixel Count: 6
Pre-amble: 255
Post-amble: 0, 0

With device_repeat set to 0:

[255, RGB1, RGB2, RGB3, RGB4, RGB5, RGB6, 0, 0]

With device_repeat set to 1 (6 endpoints with 1 pixel each):

[255, RGB1, 0, 0, 255, RGB2, 0, 0, 255, RGB3, 0, 0, 255, RGB4, 0, 0, 255, RGB5, 0, 0, 255, RGB6, 0, 0]

With device_repeat set to 2 (3 endpoints with 2 pixels each):

[255, RGB1, RGB2, 0, 0, 255, RGB3, RGB4, 0, 0, 255, RGB5, RGB6, 0, 0]

With device_repeat set to 3 (2 endpoints with 3 pixels each):

[255, RGB1, RGB2, RGB3, 0, 0, 255, RGB4, RGB5, RGB6, 0, 0]

With device_repeat set to 4 (1 endpoint with 4 pixels, last 2 pixels dropped):

[255, RGB1, RGB2, RGB3, RGB4, 0, 0]