centos7 安裝ffmpeg
CentOS 6和7安裝方法是不一樣的，下面分別說明：
安裝前都需要先安裝epel擴充套件源
yum -y install epel-release
CentOS 6比較簡單，安裝yum源之後直接安裝即可：
su -c 'yum localinstall --nogpgcheck https://download1.rpmfusion.org/free/el/rpmfusion-free-release-6.noarch.rpm https://download1.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-6.noarch.rpm'
yum -y install ffmpeg ffmpeg-devel
而CentOS 7需額外安裝擴充套件源：
su -c 'yum localinstall --nogpgcheck https://download1.rpmfusion.org/free/el/rpmfusion-free-release-7.noarch.rpm https://download1.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-7.noarch.rpm'
rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm
yum -y install ffmpeg ffmpeg-devel
檢視版本ffmpeg -version
轉換視訊命令
ffmpeg -i 72Z888piCcTP.mp4 -y a.mp4
截圖命令
ffmpeg -i test.asf -y -f image2 -t 0.001 -s 352x240 a.jpg