func NewCameraCapture(index int) *Capture {
	cap := C.cvCreateCameraCapture(C.int(index))
	return (*Capture)(cap)
}
func NewCameraCapture(index int) *Capture {
	cap := C.cvCreateCameraCapture(C.int(index))
	return (*Capture)(cap)
}
/* start capturing frames from camera: index = camera_index + domain_offset (CV_CAP_*) */