自由阿草安装EPEL Release，因为安装需要使用其他的repo源，所以需要EPEL支持
yum install -y epel-release
sudo rpm –import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm
yum安装ffmpeg
yum install -y ffmpeg
