说明：  采用V4L2（video4 linux2）编程，在开发板上实现视频监控。开发板的USB外界摄像头后，运行该程序可在屏幕上看到实时监控画面。在V4L2中，视频设备被看作一个文件。打开设备文件后，获取设备的capability，检测视频设备支持标准，进而设定视频采集方式（内存映射的采集方式），捕捉到的图像数据利用yuv格式转换为rgb格式的算法进行处理，处理后的图像数据循环入队列缓存，并重新采集下一张视频数据。
(Using V4L2 the (Video4 linux2), programming, development board video surveillance. Development board USB external camera, run the program on the screen to see the real-time monitoring screen. V4L2 video device as a file. Open the device file, get the equipment Capability detection video equipment supports standard, and then set the video capture mode (collection) of the memory-mapped image data captured using the YUV format conversion algorithm for RGB format for processing, after processing The image data cycle into the the queue cache and re-capture the next video data.)