1. opencv需要使用3.3.1的版本，在cmake list中，
find_package(OpenCV 3.3.1 REQUIRED )
2. 编译时报错，ffmpeg相关，error: 'CODEC_FLAG_GLOBAL_HEADER' was not declared in this scope
使用https://blog.csdn.net/goodxin_ie/article/details/82856008
3. signal.hpp:109:79: error: ‘decay_t’ is not a member of ‘std’; did you mean ‘decay’?
c++ error: ‘decay_t’ is not a member of ‘std’解决方法_Lkilvin的博客-CSDN博客_decay_t
cmakelist改成c++14就好了
