This is more of an aide-mémoire for me than a public guide. If it is helpful for other people then I am happy to make it available. If anyone has any comments or suggestion please contact me.
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After installing Ubuntu from scratch and if you are trying to use FFMPEG to encode ‘aac’ audio streams you may find you are missing the ‘libfaac’ library. It is simple enough to install using apt-get:
sudo wget http://www.medibuntu.org/sources.list.d/`lsb_release -cs`.list --output-document=/etc/apt/sources.list.d/medibuntu.list && sudo apt-get -q update && sudo apt-get --yes -q --allow-unauthenticated install medibuntu-keyring && sudo apt-get -q update
sudo apt-get install ffmpeg libavcodec-extra-52
And you will now have the library available…