dont worry about the ssc stuff, thats just for embedded systems like the slug. You are transcoding with ffmpeg.
The avahi messages are nothing you can do anything about, thats up to a dev to fix.
The most likely cause is that your database is corrupted, and firefyl cannot update it. Rename it and see if that fixes it.
You might also change to sqlite3 while you’re at it, which will break compatibility with your old database for good, but it’s usually worth it since sqlite3 is stabler.