rtsp直播v4l2摄像头

参考博客：http://www.cnblogs.com/cslunatic/p/3579706.html

关于video4linux2(v4l2) api 很详细介绍的链接：

http://linuxtv.org/downloads/v4l-dvb-apis/

http://lwn.net/Articles/203924/

http://www.cnblogs.com/mlj318/archive/2013/01/23/2872932.html

http://blog.csdn.net/firehood_/article/details/16844397