Send ArtNet to localhost

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Bruno Carneiro

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Nov 17, 2016, 6:31:33 AM11/17/16
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Hi! Congratulations on the great work to all the people on f53! All the new features are so exciting!

I would like to put QLab with lights to work asap. Currently I'm using the OLA (https://www.openlighting.org/ola/) to wire LX software to my USB DMX interface. I have to send ArtNet to the localhost for that to work. I can't seem to get it working with QLab. Am I missing anything? Thanks

Bruno Carneiro

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Nov 17, 2016, 8:41:58 AM11/17/16
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Answering my own question: open "QLab Preferences", tick "Use Broadcast mode for Art-Net lightning". It's a workaround for now, but works perfectly in this situation. 

For anyone who may care, you could use this OLA framework to make QLab compatible with several different USB DMX interfaces, go to their website for more info.

Christopher Ashworth

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Nov 17, 2016, 9:10:12 AM11/17/16
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Hi Bruno!

Perhaps this is a case of the end client not supporting Art-Net polling? In which case it would only respond to broadcast messages, and I believe this would be the expected behavior. (Rather than being a workaround.)

Cheers,
Chris 

(mobile)
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Bruno Carneiro

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Nov 17, 2016, 12:02:43 PM11/17/16
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Hey Chris! I see... I'm doing some research on this. I'll get back when I have some answers... Thanks!

Bruno Carneiro

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Nov 18, 2016, 8:22:43 AM11/18/16
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I ran some tests here and here's what I found out:

If I turn the wifi ON and connect to a network, both LXConsole and QLC+ will find the artnet node on my own computer. QLab won't. 
If I turn the wifi OFF all of them cannot find a node on localhost, which maybe is expected behaviour as you said.

I don't know how much of an issue this is for everyone. I can get the loopback interface working just fine with broadcast. But maybe you could consider adding the option to unicast artnet packets? 

Bruno

On Thursday, November 17, 2016 at 9:31:33 AM UTC-2, Bruno Carneiro wrote:

Chad Sellers

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Nov 18, 2016, 3:44:52 PM11/18/16
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Hello,

I just wanted to clarify what’s going on here a bit.

First - a little background on Art-Net. Art-Net sends DMX data to Art-Net nodes. It can do this in one of a few ways:
1) The preferred method is to use Art-Net’s built-in discovery protocol. With this, the controller (QLab in this case) broadcasts a poll to the network asking for Art-Net nodes. The Art-Net nodes reply with information about themselves, such as which universes they care about. The controller (QLab) can then send them the DMX data they need directly (not broadcast).
2) The simpler thing to do is simply broadcast all DMX packets to the entire network. The controller doesn’t need to learn about what nodes are on the network, because it sends all DMX data to everything on the network. This is what QLab does if you check the broadcast checkbox in QLab’s preferences (though QLab will still poll for informational purposes, so you can see your Art-Net nodes in the Workspace Status window).
3) Some applications have a manual unicast mode in which the user can enter an IP address to send directly to. QLab currently does not support this mode.

Art-Net is not really designed to have multiple services speaking it on the same machine at the same time. It’s a UDP service, and to receive Art-Net traffic an application must bind to a specific port (6454). QLab binds to this port to receive Art-Net poll replies, which tell QLab about nodes on the network. OLA binds to this port to receive Art-Net DMX traffic. And OS X usually won’t let two applications bind to the same port.

So, when you try to use QLab in the preferred discovery mode with OLA, it does not work because only one of them is able to bind to port 6454. If you launch OLA first, it will bind. QLab will log an error to the system log that it was unable to bind. QLab will send out poll packets, but it could never receive the response because it failed to bind the port to start listening.

If you use QLab in broadcast mode, things can work assuming you start OLA first. If you start QLab first, it will bind the port and OLA will fail to bind. But if you start OLA first, it will be able to receive DMX traffic and QLab will broadcast it. QLab will still log a message about failing to bind the Art-Net port, but that will not prevent it from broadcasting.

I hope that helps.

Thanks,
Chad Sellers


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Sam Kusnetz

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Nov 18, 2016, 3:50:19 PM11/18/16
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For those of you who don’t know him, Chad is one of the developers at Figure 53, and he took the lead in creating Light cue and all of QLab 4’s lighting powers.

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Bruno Carneiro

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Nov 18, 2016, 4:28:35 PM11/18/16
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I LOVE YOU!

Thanks a lot, lol. I sensed there was something wrong, but could not put my finger on it. I can confirm there were issues with OLA if I started QLab first. Other than that, it seems like a solid platform for lower budget shows if you need to use a USB interface. 
Thanks again Chad! 

Bruno
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Chad Sellers

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Dec 1, 2016, 4:51:31 PM12/1/16
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Just an update on this. QLab 4.0.3 has a change in it that will allow multiple apps to bind tot he Art-Net port on the same device. You should still use broadcast mode in QLab if you want to send Art-Net traffic locally to ensure that all apps listening for Art-Net traffic get it. The functional change for this situation is that you no longer have to worry about which app is launched first. You should now be able to launch QLab and OLA in any order you like.

Thanks,
Chad


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Scott McGlynn

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Dec 2, 2016, 5:27:58 PM12/2/16
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Hey all,

I've used this thread to attempt a Qlab to DMX solution in our theatre but have run into a dead end. Can someone tell me what I'm missing?

I have an Enttec USBDMX Pro that has the drivers installed and the testing widget sends DMX out successfully.

I have installed OLA and patched the Enttec and can successfully send commands to it using ola-dmxconsole.

I have the most recent version of Qlab 4.0.3 and can confirm that it sees the OLA daemon as an ArtNet location.

No messages appear to be getting from Qlab to OLA. I've checked that the ArtNet Universe is correct (although I've not seen a subnet parameter in my OLA patching instruction so I'm not sure about that).

Either I'm missing a step or messed up a step. I'm not sure what to even open up for logs to see whether or note Qlab and OLA are communicating or not.

Advice?

Thank you,

Scott McGlynn

Bruno Carneiro

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Dec 2, 2016, 8:56:59 PM12/2/16
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Did you check the "Use broadcast mode for Art-Net lightning" box under QLab->QLab Preferences?

Bruno Carneiro

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Dec 2, 2016, 8:59:01 PM12/2/16
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👍👍👍

Scott McGlynn

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Dec 6, 2016, 1:10:38 AM12/6/16
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I solved it and will share here in case any one else has similar issues. 

Turns out that there was one more configuration I needed to do in OLA that I hadn't run across in any of the documentation. When I open the Web interface for OLA (http://localhost:9090) to access the settings there is a setting in there to try using an experimental new web interface. Clicking on that led me to a screen that has two columns: Input and Output. Each possible interface was listed on both sides with checkboxes for activating what you need. Qlab was active on the input side but there was nothing checked on the output side. Once I checked the box for Enttec USBDMX Pro, all kinds of goodness happened.

I suspect that this step was likely documented and is accessible via OLA command configuration (which is how I set up the rest of it) and I simply missed it. That new web interface makes it really obvious and simple to see the disconnected patch.

And I did indeed have broadcast mode enabled in Qlab.

Scott McGlynn
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