if they have to be exactly in Sync, i would recommend networking the machines together and using Michel's SyncVideo actor. you could then trigger them at any time.
@fubbi yes and it is useful to calculate the lenghtr of the curb ;)
you juts feed the signal from a single movie player into 2 projector actors that go to different physical outputs.
@eamon You can also use Get Stage Size and Chopper to make your life easier and only send the proper feed to the proper Projector
I just know 2 pieces of software capable to play video on IOS devices with OSC trigger:
The mentioned Multivid
There is its OSC API
And quite new one: TouchViZ from Hexler. It have an extensive OSC API: https://hexler.net/docs/touchviz-osc-reference
@michel thank you michel