Как установить ffmpeg? [дубликат]

Я попытался установить ffmpeg в trusty / Ubuntu 14.04 и получил следующее сообщение:

$sudo apt-get install ffmpeg

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package ffmpeg is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'ffmpeg' has no installation candidate

Почему пакет недоступен?