libmmbd / libaacs VID discrepancy.

[EdibleFungi]

I am making a project using both libaacs and libmmbd.

Ever since a MKBv82 disc failed to decrypt and noticing that a combination of the MKB tarball, libaacs (via aacs_info) and then makemkv could solve the issue together, I wanted to integrate the two together to make the process more streamlined using the libraries directly, however I noticed that the VID provided via libmmbd differs from the VID on the discatt.dat file provided on the MKB_vXX_... or the VID provided by regular libaacs.

Namely, for the film "The Martian"

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# libaacs (correct VID)
Disc ID: 5092F78585795CC0973D891202FA9BA7B51C1649
VID    : 3304ABC79A028FE377D4C1F6B3D42BCD

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# libmmbd (wrong VID and some different bytes every time)
Disc ID: 5092F78585795CC0973D891202FA9BA7B51C1649
VID    : 95F5540E781B4244CFFC3ECDA5215CC9
...
Disc ID: 5092F78585795CC0973D891202FA9BA7B51C1649
VID    : 9555C235351842440B0A23CCF965A9B9

Is there anything i can do to fix that up?

[EdibleFungi]

The result from libmmbd's aacs_get_vid looks like dirty memory. Library might be returning some stale memory instead of the correct value pointer (or a null pointer / null key if not valid).

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95 f5 54 0e 78 1b 42 44  cf fc 3e cd a5 21 5c c9  |..T.x.BD..>..!\.|
95 55 c2 35 35 18 42 44  0b 0a 23 cc f9 65 a9 b9  |.U.55.BD..#..e..|

[MrPenguin]

The result from libmmbd's aacs_get_vid looks like dirty memory. Library might be returning some stale memory instead of the correct value pointer (or a null pointer / null key if not valid).

According to the source code, libmmbd's aacs_get_vid() function doesn't even try to return the VID.

As I understand it, libmmbd contains an alternative implementation of libaacs, so you should link your application to either libmmbd or libaacs, but not both as they are mutually exclusive. The Open Source libbluray library can load a libaacs library dynamically, thus choosing libmmbd over the OpenSource libaacs variant, and so allowing applications linked to libbluray to use MakeMKV's "hashed keys" database instead of the usual KEYDB.cfg file.