ffmpeg: error while loading shared libraries: libavdevice.so.57: cannot open shared object ..

::::::

sudo leafpad /etc/ld.so.conf

/usr/local/ffmpeg 目录是我ffmpeg安装目录，根据你的安装目录改吧

sudo ldconfig

:::::::::

sudo leafpad /etc/profile

export PATH="/usr/local/ffmpeg/bin:$PATH"

然后保存并运行source /etc/profile