The segfault error is an error that occurs when closing camera server, not while it's running. This is happening immediately after running camera server because systemctl detected the segfault and tried to rerun camera server (thus closing yours since only one instance of camera server can be running at a time). If you want to run camera server manually, make sure to run systemctl stop(or kill) voxl-camera-server first to make sure there's no background conflict.
The generic hal3 error codes can be found here, the -19 is a qualcomm specific one that we've found to be equivalent to ERROR_DEVICE (though we have been unable to find its proper definition), and has indicated that there is an error with the device and it will be unable to process any more requests.