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13xforever / ps3-disc-dumper

A handy utility to make decrypted PS3 disc dumps
MIT License
434 stars 29 forks source link

Multi-Extent Files #22

Closed ghost closed 5 months ago

ghost commented 2 years ago

Does this application properly handle interlaced multi-extent files? These are odd files typically found in 3D discs which use the multi-extent feature of ISO-9660 to interlace each extent with other files. It is what was fixed in this commit to libudfread, and it is the problem that was reported here for ird files. Would PS3-Disc-Dumper correctly extract the files off an image with such a file structure?

PS3-ISO-Rebuilder doesn't handle this edge case correctly. It assumes all multi-extent files are contiguous and thus calculates MD5 checksums incorrectly while also rebuilding corrupted ISOs in certain cases. I also have a suspicion that team 3K3Y's IRD programs do not handle this edge case correctly.

13xforever commented 2 years ago

I'm relying on OS UDF driver to read file contents (precisely to benefit from error correction and speed up the process). I'm only reading ISO 9660 table to get the list of all files and their sector mappings (needed to decrypt the bits of files where the filesize does not align with the integer number of sectors, which is most of the time). To parse the raw filesystem and to build the sector mappings I rely on 3rd party library DiscUtils, and as far as I'm aware there's been no issues with dumping discs with interleaved files (I do not have hybrid discs to confirm tho).

13xforever commented 5 months ago

Having tested with a few hybrid PS3 game discs (MGS Legacy Collection and Tekken Hybrid), I can't see any issues with the dumping part. As far as I can see the IRD issues were with rebuilding the ISOs back, which is not relevant to this project.

Closing for now as not affected.