I am struggling to understand problems with AACS and Blu-ray playback

InfamousMower · 2026-02-09 03:59:38

I have two Blu-ray discs that I am trying to play on my PC.

Disc 1 is from 2024, MKBv68.

It plays just fine. I followed the instructions on the wiki: https://wiki.archlinux.org/title/Blu-ray. I downloaded the KEYDB, I verified that my Disc's Volume Identifier was present with a VUK, it all looks good.

Disc 2 is from 2012, MKBv33.

It does not play. I do not know why. The VUK is present just the same as Disc 1.

$ bd_info /dev/sr0
Using libbluray version 1.4.0
mmc.c:472: Host key / Certificate (id 0xffff800001c1) has been revoked by your drive ?
aacs.c:121: No usable AACS libraries found!
dec.c:197: aacs_open() failed: -5!
Volume Identifier   : {identifier}
BluRay detected     : yes
First Play supported: yes
Top menu supported  : yes
HDMV titles         : 44
BD-J titles         : 0
UNSUPPORTED titles  : 0

BD-J detected       : no

AACS detected       : yes
libaacs detected    : yes
Disc ID             : {id}
AACS MKB version    : 33
AACS handled        : no
                      (AACS certificate revoked)

BD+ detected        : no

I have several questions.

1) Why does it matter that my certificate is revoked? I have the VUK, shouldn't libaacs use that automatically?

The entry in KEYDB says

(LEGACY) (NOTVALIDATED)

Does that mean the VUK is just wrong? Someone made a mistake when uploading this Disc's VUK?

Disc 1 also says that. Maybe I just got lucky?

2) How is my certificate revoked?

KEYDB contains a certificate that was revoked in MKBv72. How recent is that? My 2024 disc was only v68. I think the next most recent disc I have ever used with this drive (on Windows) was probably 2014. Is there a way to check what my drive has revoked?

---

More curious, I find that I can play the disc after installing makemkv and loading the sg kernel module. I don't have to launch makemkv, just having it installed is enough. To be clear, I did launch it, but uninstalling makemkv causes the disc to be unable to be played again, and after re-installing, no launch is required. I can't ever go back to a state before I had launched it, so I can't verify.

3) What in the world is going on here?

What does installing makemkv do that makes it playable? It doesn't modify the KEYDB. I'm still using the same libaacs, the makemkv-libaacs is a separate package from makemkv that isn't pulled in as a dependency.

It's curious that the sg module is required only for Disc 2. I did verify that the module alone was insufficient to play the disc.

Part of me wants to say that I should just be happy that it plays and move on. But I can't let the curiosity go. How does this work? How does makemkv change the behavior of libbluray and libaacs? What steps could I take to investigate further?

Last edited by InfamousMower (2026-02-09 04:00:15)

seth · 2026-02-09 11:02:37

https://wiki.archlinux.org/title/Blu-ra … on_process
https://www.reddit.com/r/VLC/comments/r … libraries/
If it's not the KEYDB.cfg path, maybe either the MKB or VUK are wrong?

Since sg is relevant you probably need that for the MKB - sure the other disk isn't decrypted the "legal" way and then also stored in ~/.cache/aacs/vuk ?
You've verified that just loading sg doesn't suffice?
https://wiki.archlinux.org/title/Blu-ra … l_not_play

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#1 2026-02-09 03:59:38

I am struggling to understand problems with AACS and Blu-ray playback

#2 2026-02-09 11:02:37

Re: I am struggling to understand problems with AACS and Blu-ray playback

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