Thanks Greg — that article answers my questions 2 and 3. The AVCaptureDeviceDirectionCoordinator + descriptor-swap-inside-beginConfiguration pattern is exactly what I needed for uninterrupted broadcasts, and the mirroring-from-the-direction-map note would have bitten me for sure. One thing the article doesn't address is my question 1: is AVCaptureMultiCamSession supported on iPhone Duo — specifically streaming two cameras that face opposite directions simultaneously (e.g. .builtInInnerUltraWideCamera + .builtInOuterUltraWideCamera, or the Virtual Front Camera plus a backward-facing camera)? I noticed the article recommends single-input reconfiguration over multi-cam; is that a performance recommendation, or is opposite-direction multi-cam unavailable on this device? Our use case is a live co-cast where one host fills two video panes: their face and what they're looking at.