I was having the same issue. My app would crash when I would log the AVMetadataMachineReadableCodeObject
stringValue.
My original code that would crash:
NSLog("%@", [machineReadableCodeObject stringValue]);
Once I decoded the stringValue with stringByReplacingPercentEscapesUsingEncoding
it does not crash anymore:
NSString* decodedValue = [[machineReadableCodeObject stringValue] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog("%@", decodedValue);