I was at our fair last night with my P4 an Mavic with the permission of the fair board. I was mapping the flow of the people before and during the main acts. This was the 1st time using this app.  We screened to face book, but the delay was 10 min.  Any way to screen directly to a computer with out a long delay.

I would recommend using an HDMI module to transmit the live image transmission to a computer or other screens for your Phantom 4.
It might relate to the internet about the delay of the Facebook live stream if the app's transmission is in real-time. So please ensure a good internet condition on the mobile device.