JFK UHD - other playlists on disc?

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ben_uk
Posts: 76
Joined: Mon Feb 01, 2021 11:41 am

JFK UHD - other playlists on disc?

Post by ben_uk »

Hey there,

I’ve managed to rip the 90GB file perfectly fine, however on the disc are 3 other playlists with quite large file sizes, something like 26GB, 36GB and 22GB.

Anyone know what these other ones are?
dcoke22
Posts: 3177
Joined: Wed Jul 22, 2020 11:25 pm

Re: JFK UHD - other playlists on disc?

Post by dcoke22 »

DVDCompare.net for the JFK 4K UHD release suggests that only the director's cut version of the movie is on UHD.

The largest UHDs are triple layer discs that can hold about 100GB of data. If the Director's Cut of the movie is 90GB, then there's not enough space left on the disc for another 84GB of unique data.

Blu-rays and UHDs have a feature called seamless branching. This feature allows for a movie to be cut up into segments. The player can seamlessly finish playing one segment and start playing the next segment without the user noticing. This is often used to put multiple versions of a movie on a single disc. Instead of two copies of the movie on the disc, the whole thing is chopped into segments. There's one title that's all the segments for one version of the movie and another title that's all the segments for the other version of the movie. Probably most of the segments are the same between the two versions.

The segments are named with 5 digit numbers and if you use MakeMKV to create a decrypted backup of a blu-ray, you can find the segments in the BDMV/STREAM folder. There will be #####.m2ts files in there, playable with most players like VLC. When you highlight a title in MakeMKV, on the right side in the information window there's a line about the segment map. The segment map is the in-order list of segments that make up that title. It might be one segment or many segments depending on the whims of the disc's author.

Often there's a .mpls file associated with a title. You can think of a .mpls file as a playlist of segments. There's other data contained in a .mpls file, like chapters. Again, if a title is highlighted in MakeMKV, the line about source file name will list the .mpls that defines that title if there is one. If there isn't a .mpls that defines that title, then the source file name will show the name of the .m2ts file and that title will match the segment map.

Oftentimes disc extras are just a single segment (a single .m2ts file). The menu system of the blu-ray allows access to it directly so there's no need to define a .mpls file for it. Because of this, MakeMKV examines all the .mpls files on a disc and it examines all the .m2ts files on a disc. It adds titles for all the .mpls and .m2ts files it thinks are appropriate. When you open a disc in MakeMKV you can see a bunch of entries in the log about what MakeMKV does and does not add as a title. And sometimes it gets confused and adds segments that are actually part of the movie as an independent title.

So, if you highlight the movie in MakeMKV and take note of the segment map and then highlight the other titles you might discover that they're just a single segment that's already part of the movie. Or, if they're not segments that are part of the movie, then rip them, figure out what they are and report back! :)
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