Error !!!

Undefined symbols for architecture armv7:

  "_OBJC_CLASS_$_AVCaptureVideoDataOutput", referenced from:

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

  "_OBJC_CLASS_$_AVCaptureDeviceInput", referenced from:

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

  "_OBJC_CLASS_$_AVCaptureSession", referenced from:

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

  "_CMSampleBufferGetImageBuffer", referenced from:

      l4075 in libQCAR.a(libQCAR.a-armv7-master.o)

  "_AVMediaTypeVideo", referenced from:

      +[OverlayViewController determineCameraCapabilities:] in OverlayViewController.o

      l4113 in libQCAR.a(libQCAR.a-armv7-master.o)

      l4130 in libQCAR.a(libQCAR.a-armv7-master.o)

      l4135 in libQCAR.a(libQCAR.a-armv7-master.o)

  "_OBJC_CLASS_$_AVCaptureConnection", referenced from:

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

  "_OBJC_CLASS_$_CMMotionManager", referenced from:

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

  "_CMTimeMake", referenced from:

      l4135 in libQCAR.a(libQCAR.a-armv7-master.o)

  "_OBJC_CLASS_$_AVCaptureDevice", referenced from:

      objc-class-ref in OverlayViewController.o

      objc-class-ref in libQCAR.a(libQCAR.a-armv7-master.o)

ld: symbol(s) not found for architecture armv7