opencv调用libv4l打开摄像头失败

为了获得usb摄像头数据，移植opencv时选上了withl ibV4L,程序里运行到cvCreateCameraCapture之后出现如下错误信息：
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
VIDIOC_QUERYMENU: Invalid argument
libv4l2: error allocating conversion buffer
mmap: Cannot allocate memory
munmap: Invalid argument
munmap: Invalid argument
munmap: Invalid argument
munmap: Invalid argument
Unable to stop the stream.: Bad file descriptor
munmap: Invalid argument
munmap: Invalid argument
munmap: Invalid argument
munmap: Invalid argument
libv4l1: error allocating v4l1 buffer: Cannot allocate memory
HIGHGUI ERROR: V4L: Mapping Memmory from video source error: Invalid argument

我也准备学OPENCV啦。求指导啊