How can I capture/record Front Camera of iPhone ?

I’m trying to figure out how can I capture the iPhone front camera video through of Unreal.
I created a FaceAR for my character and I record her face movements by the sequencer, but I need to capture/record the video of Front Camera of iPhone for to compare the Facial movements and 3D movements in the same time and to this, I need to activate the Record video of Front Camera to save videos on own iPhone. How can I do this through Unreal?
Someone can give one light.

Thanks, folks…