Fix 'Missing AACS configuration file' in VLC BD (2022):
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1. Install the required libraries sudo apt install libaacs-dev libbluray2

2. Download the KEYDB.cfg file from http://fvonline-db.bplaced.net/

3. Extract the .ZIP file

4. Inside the keydb_eng folder is keydb.cfg rename this to KEYDB.cfg (It's case sensitive.) and move it into ~/.config/aacs (You might need to create this folder manually if it doesn't exist.)

5. Open VLC and try to open the disk. If the decryption key is known and present in the database then it should work fine, otherwise if it's a very recent Bluray you can download a new copy of the database at a later date and hope someone has added the decryption key for your disk.

Source: https://askubuntu.com/questions/1325752/missing-aacs-configuration-file-error-when-playing-blueray-movies
Date: May 23rd 2022