Multiple scenes to multiple (separate) screens

[dvdan]

Just upgraded to v2, and trying to figure out how to do something I was able to do with v1. Set up multiple scenes, and direct them to different full screen displays. This allowed me to visualize multi-channel audio and run the video outputs to different inputs on a video mixer. Four machines gave me 8 HD channels, which was great.
Now it appears the fullscreen behavior is a bit different. It cycles through the different screens one at a time, as it used to, but then it tries to span the outputs which is not what I'm looking for. I can set up multiple scenes on different tabs, but only one outputs at a time.
I can't remember exactly how I used to do it, but it might have involved running more than one instance of MAGIC. Then I was able to run each one to a different fullscreen output, and patch each scene in a separate window. Is this still possible?

[Sadler]

Assuming your comp resolution is 3840x1080...

multi_screen.png (42.32 KiB) Viewed 2640 times

I don't remember ever being able to output different scenes to each projector but its been years since spanning was available.

[Terry Payman]

I've used two separate instances of Magic V2 to output fullscreen to different inputs on a video mixer. I've also used spanning but I prefer two instances as they still give one usable output if (eg) a rogue plugin crashes any one instance of Magic.

From memory, I think I just added "-mi" to the shortcut I used to start instances. I don't have any of those systems immediately to hand but I'll look it up if you have any difficulty.

I would prefer (and have requested) a deterministic means of assigning the output screen. This would preserve the assignment even if an instance needed to be re-started or the connected output was momentarily disconnected.

[dvdan]

"./Magic -mi" from a terminal did it! thank you so much Terry and Sadler for the prompt replies. Also cool to learn what "SceneInput" is for, think that's new since v1.

[Eric]

Yes, both the "-mi" flag and display spanning should be considered solutions. Each has its advantages/disadvantages.

The "-mi" flag is probably more computationally efficient (allowing better parallel performance on the same processor) but it is less memory-efficient if your scenes share a lot of common assets/effects. Also, not all sound cards can be used in two different applications at the same time.

The "-mi" flag was available in the later versions of V1 so that's probably what you're remembering. The SceneInput module was also available in the later versions of V1.

Display spanning was added in V2.

[KingSculpin]

Thanks for posting this. I searched the forum and found this thread... exactly what I'm looking for!

I'm still a little confused, however. Could someone please clarify what a "-mi" flag is?

"./Magic -mi" from a terminal

Stupid question... what is a terminal?

I just added "-mi" to the shortcut

Windows gives me an error when I add -mi to the end of the shortcut. What could I be doing wrong?

[Eric]

On Windows it should look like this:

Capture.PNG (23.81 KiB) Viewed 486 times

[Terry Payman]

Could someone please clarify what a "-mi" flag is?

It's an example of a "feature flag", used to enable a particular feature.
"mi" stands for"multiple instance", ie more than one instance of Magic running at the same time.
"mi" is passed to the Magic program when it starts, changing the behaviour to allow a further instance to start if another is already running.

In another thread, Eric wrote

" ... It's experimental, but the users who've tried it seem to think it works well. The only problem I've encountered is that you can't use an ASIO audio device more than once. ... You can do it as many times as you like, and go fullscreen on whichever monitors you like. The cool thing about it is you can either load the same project, or completely different projects."
https://magicmusicvisuals.com/forums/viewtopic.php?t=328#p1819

[Eric]

Yes, and to further clarify, the standard Windows behavior is that if a program is already running, and you try to launch it again (by double-clicking its icon, for example), you will just be shown the already-running program.

But if you launch Magic with the -mi flag, and then you try to launch it again, you will get a brand new instance of the program, meaning Magic will be running twice -- completely independently. You can do this as many times as you need (i.e., if you have 3 or 4 or 6 or 10 output monitors), but obviously your system will run more slowly with each one.

[KingSculpin]

Thank you very much Eric and Terry! That helps a lot.

Is this a new feature of v2.3? I was trying -mi on the Demo version on my secondary laptop... that's probably why it wasn't working.

I'll try it again on the full version of v2.3 (on my main PC) when I get home.

[Terry Payman]

... Is this a new feature of v2.3?...

The "-mi" feature been there for ages - certainly since 2015, the date on the forum post that I linked above.

I've been using it during live performances to give two independent Magic outputs from my PC. I cross-fade between them using an external video mixer, enabling me to load a new project into one instance of Magic whilst presenting the output of the other to the audience.

[KingSculpin]

It worked! Thanks again for your help. I'm currently using multiple very low-end laptops.

I intend to build a custom PC soon, which can run all my visualizers at once on multiple monitors I'm very excited