I was trying to play some .avi files tonight with various players using the Xine engine, including Totem and xine-ui. I was getting an error like “there is no demuxer plugin available to handle … .avi” And even Amarok (which also uses xine) was complaining about playing .mp3s.
After some Googling I found a blog post that did it for me, super easy fix and worked like a charm.
Just delete the file “~/.xine/catalog.cache”
(Command: “rm ~/.xine/catalog.cache”)
Much thanks to tobias at https://www.weisserth.eu/