具体错误：
Package ffnvcodec was not found in the pkg-config search path.
Perhaps you should add the directory containing `ffnvcodec.pc'
to the PKG_CONFIG_PATH environment variable
No package 'ffnvcodec' found
这是因为没有安装nv-codec-headers。具体参考：
https://blog.csdn.net/quantum7/article/details/106968971
