Having a live video source for visuals can be as valuable as having a microphone in audio. But now you can add iOS devices to the realm of possible input devices.
On the Mac, you’ve got several means to do this.
Wired: With a recent version of iOS / macOS, just connect your Lightning cable, and you can use the iPhone like any other input. (You’ll need a Mac app that supports AVFoundation.)
Wireless: AirBeam is a combination of mobile iPad/iPhone and desktop Mac app. The iOS app is US$3.99, and then apps for Apple TV and Mac are free. The trick that makes this cool is that the macOS version has Syphon. Using that tool for inter-app video, you can pipe video to supported apps like VDMX, Resolume, and others.
Windows lacks both of those options. Now, someone could roll a solution that combines support for Spout with some sort of streaming from iOS. (Did I miss that? Or someone want to try that with me, say with openFrameworks?) Spout is quite cool; see this Resolume blog entry for a taste.
In the meantime, though, there are options. The best one I could find is from the makers of the excellent iDisplay:
It maxes out at 640×480 but does work wirelessly.
I think a better option long-term would be to build a Windows client with Spout support to use with the existing AirBeam mobile app.
For more on this, our friends at Vidvox have put together nice tutorials for their Mac app.
Using an iOS Device as a Live Camera Source in VDMX [Vidvox]
Remember, you can always get Motion coverage on CDM by heading to http://cdm.link/category/motion/ or clicking/tapping ‘Motion.’