LewLight Entertainment Technology

Some thoughts and ideas for Art-Net, part 1

November 01, 2013

One of the most common ways of transporting DMX in our industry today is by means of the ethernet protocol Art-Net. I think it's fair to say that it has revolutionized our industry as a business-enabler for many manufacturers that deliver only pieces of the great technological puzzle that make up a show today. Having said that, Art-Net is also the reason for a fair amount of the support tickets that we see at Capture.

There can only be four

Let's start with some low-hanging fruit. Art-Net originated as the proprietary protocol of Artistic Licence, created to link its DMX over ethernet-gear. As Art- Net was made open it also meant that any other manufacturers could create equipment that would speak Art-Net, including software. This is where the problems begin.

The devices that Art-Net was designed for were typically 1 to 4-port boxes that would either take DMX in or out of your network. However, a lighting console or a visualizer could easily be interested in transmitting or receiving more than 4 DMX universes. In the beginning this wasn't really an issue as most developers always broadcasted all the Art-Net 'ArtDmx' packets to the entire network (known as "all network broadcast", 255.255.255.255) anyway. This was neither elegant nor really in line with the protocol specification, but it worked.

Today (and perhaps back then as well, I frankly don't quite remember) the recommended method is to first determine who on the network is interested in receiving which bits of DMX, and then specifically sending those bits only and directly to them. This is done by means of broadcasting an 'ArtPoll' message, instructing all parties to answer with an 'ArtPollReply' message, wherin they may specify which four DMX universes they would like to receive.

Yep, four is the max. So, if your product is a visualizer and you would like to provide a plug and play experience, allowing the user to see and choose between all Art-Net universes being transmitted (you guessed it - noone can report sending more than four universes either), you're out of luck.

Here's an advice to all all software manufacturers: make sure to provide the user with an option to always broadcast all DMX universes.


History  

Full opening of the CITP protocol
March 13, 2016

The pitfalls of CAD
November 06, 2015

It's Chinese
August 08, 2014

PixelBeetle 1.1 update
June 25, 2014

Introducing PixelBeetle!
March 08, 2014

Some thoughts and ideas for Art-Net, part 3
December 28, 2013

Some thoughts and ideas for Art-Net, part 2
November 02, 2013

Some thoughts and ideas for Art-Net, part 1
November 01, 2013

Well hello there!
October 26, 2013