Oh... I write it with other sample it works. Thank you.

Sorry and where is "foundSpatialFormat" used for?

If I modified codes as you provide, it seems to be able to record the spatial video, but the camera preview will stop. After pressing the record button and startRecording, it seems running but no record leave. Maybe we need some more detail for the preview using dualwidth camera

I found the solution is to remove the app on the iPhone, then reboot the iPhone to clear caches. Then build the app into iPhone again.