video_window      255 include/linux/videodev.h #define VIDIOCGWIN		_IOR('v',9, struct video_window)	/* Get the video overlay window */
video_window      256 include/linux/videodev.h #define VIDIOCSWIN		_IOW('v',10, struct video_window)	/* Set the video overlay window - passes clip list for hardware smarts , chromakey etc */