声明：转载几篇相关的技术博文。
ioctl:https://www.cnblogs.com/geneil/archive/2011/12/04/2275372.html
v4l2:https://www.cnblogs.com/silence-hust/p/4464291.html
framebuffer app:https://www.cnblogs.com/cxjchen/archive/2013/05/13/3075490.html
https://www.cnblogs.com/aquafly/p/6474555.html