Why do BD all have multiple files the same size (say 32.3GB)

[wantonsoup]

Why is the same movie on a BD multiple times? All my discs have more than one huge file, they're the same size (tens of GB, so it's the main feature, not an extra). Sometimes one has chapters and one doesn't. But sometimes they are identical. And sometimes there are THREE on a disc.

Why? What's going on? And... do I always go for the first one on the MKV list? I've been ripping ALL of them but that's going to glut my Hard Drive pretty quick and I still don't know which one to watch.

Thanks for your help. I know this asked a lot, but I can't find a definitive answer.

[Woodstock]

Because you bought a disk distributed by Lionsgate. That is a form of copy protection they use, to little avail, other than to create lots of topics on "What's the correct playlist for [insert title here]?".

[wantonsoup]

I've read about that, but that can't be it here. I'm talking EVERY disc I put in. Discs from WB, Fox, Universal, MGM, etc. They ALL have the big file duplicated.

Also - if it is the Lionsgate thing, are the duplicated bad in some way? Does it just not matter then?

[Woodstock]

In the case of Lionsgate, you have dozens or hundreds of files, only one of which is good.

Disney, especially on animated projects, have two or three files, differing only in the language displayed in the opening titles and credits. English is usually the first one, with 800 in its file name.

Others can have "director's cut" versions, which differ in a few scenes. Which one you want depends upon whether you want the theatrical release or the "special edition".

In all cases, the "huge files" are constructed out of pieces on the disks, using a thing called "seamless branching".

[solidus28]

I'll also add, in regards to there sometimes being one title with chapters and one without, but same size, I've never had a problem *only* ripping the one with chapters. I'm not sure why the other one is there, but my logic has always been that the legit playlist would have chapters. Hasn't failed me yet, I've never ripped the one without chapters.

[preserve]

In the case of one with chapters and one without - one is the mpls playlist (with chapters) and one is the source m2ts file (without).