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Live Video on Q-Lab 4

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I am posing a query here, as I know that what is in my head can in theory be done, I am just unsure of exactly how to implement it.

I am looking to update video playback within my theatre, the current setup uses powerpoint from a PC directly to a projector, simple and easy enough - however, multiple powerpoint files are required as the preshow, 5 mins prior to curtain, interval, 5 mins prior to curtain and post show 'B-Roll' are all essentially differently.  Whilst the current setup is not that clumsy, save for powering the projector off and on with the remote, I have been thinking of upgrading the system to run through Q-Lab.


The projector can be controlled through TCP/IP protocol over Ethernet connection, so I know that in theory I should be able to write OSC cues in Q-Lab to both power the projector on and off, as well as mute and unmute the projector, solving that clumsiness.

The 5 minutes prior to curtain for both pre show and interval, as well as the post show B-Rolls are all essentially identical and I know I can simply record the powerpoint and create an mp4 file that Q-Lab can playback and loop.  Easy!

The Preshow and Interval B-Roll is essentially a collection of slides advertising future performances, these slides get updated on a weekly basis and utilise a random selection of transitions that are built in to powerpoint, rather than recording this every week, I was considering using Q-Labs live feed video feature.  My question is, really in two parts, is it possible to have another computer provide a live feed to Q-Lab (essentially a PC to a Mac) and if it is possible, what extra equipment would I need to make this work?

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To answer the questions you posted:

1. Yes, use a camera cue.

2. A capture card to take a video feed from the powerpoint pc that is supported in MacOS and QLab.

QLab can access video capture devices through camera cues, you can then apply the same geometry and effects to them as a normal video cue. If you upgrade to QLab 5 you can utilise NDI screen capture to send the video feed over a network, but for various reasons a hardware capture card is a better solution.

Control wise you would be sending TCP commands direct from QLab, not OSC. When you set the destination you can tell it what protocol it's sending. If you struggle to get it work directly, you could send OSC from QLab to companion which will probably have a nicer integration with the projector.

This is definitely a cheaper option, but a more robust solution would be to put a presentation switcher between the PC and the projector. That would allow you to switch between multiple sources cleanly, and utilise things like still stores PiP effects and being able to freeze or blackout the signal. It's also a more reliable device to be the single point of failure than either a PC or a Mac. Assuming your projector is 1080p or lower, you don't even need anything particularly fancy or recent. Something like a PDS 901/902, Analog Way Pulse2 3G, or similar Roland switcher.

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