I just pulled the linuxserver/sabnzbd container and deployed it. It works great.
I use the service in conjunction with sickchill and nzbToMedia.
nzbToMedia is run as a postprocessing script for the tv category. The software/python modules though require ffmpeg/ffprobe.
Now, I can go and install ffmpeg (apt-get update && apt-get install ffmpeg) into the container, create a new image and use that - however I would think that I am not alone in this endeavour?
Can the linuxserver/sabnzbd image be augmented to have ffmpeg?