Problem

When a USB audio interface is connected, the iOS/iPadOS Camera app does not seem to record audio or is recording silence only. 

Background

This is a known issue of the Camera app that only affects USB audio interfaces with more than two input channels. That means the problem may occur when using one of the following Steinberg interfaces:  

UR242 | UR28M | UR44 | UR44C | UR816C | UR8244

...or any other multi-channel USB audio interface on the market.  

Interfaces with stereo inputs like these Steinberg interfaces are not affected:

UR12 | UR22mkII | UR22C | UR24C

Workaround

 To restore the record ability of the Camera app, follow these steps: 

• Disconnect the USB audio interface from the Camera Connection Kit. The Camera Connection Kit should remain connected. 
• Quit the Camera app. 
• Start the Camera app. 
• Connect the USB audio interface to the Camera Connection Kit.

The Camera app will now record audio from the first two input channels.