libavcodec54 software package provides Libav codec library, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libavcodec54
libavcodec54 is installed in your system.
Make ensure the libavcodec54 package were installed using the commands given below,
$ sudo dpkg-query -l | grep libavcodec54 *
You will get with libavcodec54 package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Libraries |
| Package | libavcodec54 |
| Version | 6:9.18-0ubuntu0.14.04.1 [amd64 |
| Description | Libav codec library |
| Sub Section | libs |