$ sudo apt-get update
$ sudo apt-get install libk3b6-extracodecs 

libk3b6-extracodecs is installed in your system.

Make ensure the libk3b6-extracodecs package were installed using the commands given below,

$ sudo dpkg-query -l | grep libk3b6-extracodecs *

You will get with libk3b6-extracodecs package name, version, architecture and description in a table

libk3b6-extracodecs package basic information: