$ sudo apt-get update
$ sudo apt-get install libmpcdec6 

libmpcdec6 is installed in your system.

Make ensure the libmpcdec6 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libmpcdec6 *

You will get with libmpcdec6 package name, version, architecture and description in a table

libmpcdec6 package basic information: