libavcodec-extra-54 software package provides Libav codec library (additional codecs), 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 libavcodec-extra-54
libavcodec-extra-54 is installed in your system.
Make ensure the libavcodec-extra-54 package were installed using the commands given below,
$ sudo dpkg-query -l | grep libavcodec-extra-54 *
You will get with libavcodec-extra-54 package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Libraries |
| Package | libavcodec-extra-54 |
| Version | 6:9.18-0ubuntu0.14.04.1 [amd64 |
| Description | Libav codec library (additional codecs) |
| Sub Section | libs |