$ sudo apt-get update
$ sudo apt-get install ffmpegthumbnailer 

ffmpegthumbnailer is installed in your system.

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

$ sudo dpkg-query -l | grep ffmpegthumbnailer *

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

ffmpegthumbnailer package basic information: