V4L2_CTRL_CLASS_USER  827 include/linux/videodev2.h #define V4L2_CID_BASE			(V4L2_CTRL_CLASS_USER | 0x900)
V4L2_CTRL_CLASS_USER  832 include/linux/videodev2.h #define V4L2_CID_USER_CLASS 		(V4L2_CTRL_CLASS_USER | 1)