Feature request: FFMPEG capabilities

[madknave]

Commit https://gitlab.com/LazyLibrarian/LazyLibrarian/-/commit/fda2b28162ff659deb5dc87c323f2c68a2adf65b introduced the possibility of pre-processing audio files within the lazylibrary software, for this to happen FFMPEG capabilities are required in the container.

This request is to add FFMPEG to the container.

Cheers!

[aptalca]

This would be a good candidate for a docker mod: https://blog.linuxserver.io/2019/09/14/customizing-our-containers/#docker-mods
and https://github.com/linuxserver/docker-mods

[mKeRix]

I create a Docker mod that makes ffmpeg available to the lazylibrarian container and published it to Docker Hub. You can find the matching repository here.

Enabling it is as easy as adding mkerix/docker-ffmpeg-mod:latest to your DOCKER_MODS env variable.

[CHBMB]

@mKeRix Want to submit a PR to our docker-mods repo so it appears on our listing and then submit a PR here for the documentation?