Apple is introducing the multi-cam support which would allow apps to take photos, video, audio, metadata, and depth from multiple microphones and Cameras on a single iPhone or iPad. This is part of the feature set that we are expecting with the iOS 13, and we are excited to have it.
Multi-cam support has already been made available to a number of Android devices in some variant or form over the years. Macs have also supported this feature for a while.
This feature will allow developers create apps that stream videos or take pictures or audio using both the front camera and the rear camera at the same time. The Multi-Cam support is only going to be made available to latest devices from Apple like the iPhone XS, XS Max, XR and the latest iPad Pro (which will be through iPadOS).
There are certain combinations that can be performed on these devices. The regular and telephoto camera on the rear of the iPhone, or the selfie camera and the regular rear camera, and there are combinations that would allow the use of the TrueDepth selfie camera
The new feature was presented during WWDC, with a demo picture-in-picture video recording app that was recording the user from the front-facing camera while recording from the main camera simultaneously. The app enabled the ability to swap between the two cameras during playback in the photos app, a feature which would give developers control over the TrueDepth cameras.
Mobile devices will be limited to a single session of multi-cam unlike the mac, iPhones and iPad due to power constraints.