Cannot play UHD discs directly from drive

[TrivialMan]

I have a LibreDrive. I can use it and VLC to play any regular blu ray, dvd, or cd I've tested it with. I can also rip data from all those formats, and I can rip UHDs using MakeMKV. I can then play back the folder created by MakeMKV as though it was a disc getting menus and everything using VLC. Playback is fine on when doing this, little to no stuttering or anything.

However when I try to play a UHD directly from the disc in the blu ray drive, VLC just sort of hangs. It understands there is a disc in there and what the disc is because the background art changes to a little thumbnail to suit it and the title bar up top reflects it as well, but then just nothing happens. I can hear the drive spin for a bit before it eventually stops. I can also press stop on VLC and load up a different media source so it isn't crashing. If I choose to skip menus when I load the disc the seek bar displays an end time on the right hand side that is often accurate to the length of the movie I'm trying to watch (sometimes it's really short but I think it's getting a preview or anti-piracy message in those cases), so it is somehow getting some of the metadata, but it absolutely will not play and I cannot use the seek bar to seek.

I have no idea how to debug this. It doesn't seem like a hardware issue since, like I mentioned, I can make copies of the data on the disc and those play just fine. But it must either be an issue with my drive that is only affecting 1 type of disc, or it is an issue with VLC. VLC is the only program I have that can even play UHDs though, so I can't even compare it against anything. If anyone can point me in the right direction on how to fix this I'd really appreciate it.

[TrivialMan]

An update on this. I have found the means to play my UHDs, but something very bizarre is going on. They always play flawlessly (including interactive menus) if I follow the steps below in order, but if I don't then usually I don't get playback of any sort. They just fail completely, generating a bunch of information about "lost synchro" in VLC's messages and displaying nothing but the background thumbnail.

To play a UHD:
1. Without a disc in the drive, start an instance of MakeMKV with a valid beta key
2. Insert the UHD and let it spin up until MakeMKV recognizes it and shows its info
3. Start VLC and then play as you would any other blu-ray

Now, I am well aware that MakeMKV has an integration feature and can be used with VLC to play protected discs in this way. However, in the settings of MakeMKV I do not have that enabled. And I must reiterate, regular blu-rays and ripped copies of both normal blu-rays and UHDs saved to my SSD function perfectly. So something is wrong in one of these two programs, possibly both, that is making VLC try to rely on MakeMKV while reading from my blu-ray drive when it shouldn't. Is there a setting in VLC for enabling or disabling this feature? I'd readily believe that in the past I enabled such an option and forgot about it causing all my own problems, but I cannot find anything perusing the settings myself and Google has only led me back to this very topic when I try to search for answers.

[TrivialMan]

This is likely the final update to this saga. With the help of another individual more talented than I, I have managed to get all my UHD discs playing properly from the disc. The short version is that libaacs needs to support AACS2 drive certificates. By creating a new version of that library with that support, and coupled with the keys and such generated from FindVUK, everything is fixed. If someone stumbles on to this thread and is looking for me to tell them exactly how to alter libaacs to work as mine has, don't bother. I don't have permission to share what was given to me and I don't know how to fix things myself. Hopefully someday this fix is merged to the library proper, but for now this thread can only serve to identify definitively what the problem is. It can offer no solution.