$ sudo apt-get update
$ sudo apt-get install libffmpegthumbnailer4 

libffmpegthumbnailer4 is installed in your system.

Make ensure the libffmpegthumbnailer4 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libffmpegthumbnailer4 *

You will get with libffmpegthumbnailer4 package name, version, architecture and description in a table

libffmpegthumbnailer4 package basic information: