This is a really specific issue that I can't find info about anywhere on the internet so I bet a forum sub-category about DVDs and layers might help me. I have a rip of a game DVD here, specifically a rip of a dual-layer one. The ripping software sees it as a dual-layer disc and rips it as such, resulting in an 8.5-ish GB ISO, and game plays fine and everything, however the problem I'm facing is that ISO editing/extraction software such as ImgBurn/UltraISO/WinCDEmu/etc are unable to see the data on the second layer, thinking it's a rip of a single-layer DVD. The frustrating part is that every single rip of this specific game acts like this. The data is clearly there, as PlayStation 2 game consoles can read from it, but when ripped, only files on "Layer 0" can be read, leading all PC software to consider it a single-layer disc. Since the data is clearly there, is there a way to force ISO software to consider it a dual-layer DVD rip and to force it to start looking at "Layer 1"? I have a full listing of the files that should be there and the directories, if that helps. Also, before anyone asks, lots of technical documentation has been done on this game and it has been 100% confirmed that the files from "Layer 1" SHOULD visible from any computer, it's not intentional obfuscation from its developers, and the preservation community got a hold of a "mastering build" of this game which has all files fully visible from computer.
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The problem is the use of the ISO image file format. Since it only supports user data sectors, it cannot store specification of layer# or the layer break sector#, so ALL resulting info is ostensibly "layer 0". For DVD-Video specific burning applications, various apps can get around that because the main IFO file also keeps track of layer break sectors, and so they cheat and use the info from there, since that IFO file is always included within the ISO. There is probably a similar feature in Blu-ray videos. Other apps get around this issue by using a sidecar file (e.g. mds), but since that is mainly a limitation of the format, others just use a format that keeps track of more info about the disc structure. Cue/bin, nrg, ddp/cmf.
Also, layer is a physical designation (outside of the logical file system) so it isn't really relevant in disc image formats, except those dedicated to mastering.
Something I should also mention is that through some technical documentation, it appears that the second layer uses a second ISO filesystem. It could be that no software is capable of reading multiple filesystems in a single ISO. Do you know of a way of detecting and splitting them into two seperate ISOs?
<edit>ISOBuster would be your best bet, in terms of reading multiple/varying filesystems on discs.</edit>
I STRONLY do not recommend an app to split. Rather, if you MUST have 2 different ISOs (why?), mount the ISO so it is seen as a volume, then copy over the contents you need into separate sub-sections each in their own folder, then make each folder's contents an ISO. That way, you have total control over layout and sectioning. There are a number of options for doing Folder-->ISO.
Last edited by Cornucopia; 1st Dec 2022 at 18:25.
Maybe I'm not explaining it correctly. This specific PS2 game was mastered in a very unconventional way, likely on accident. I made an image to describe exactly how this game was mastered and why it's stupid:
Here's a screenshot of what UltraISO sees:
But here's a mockup of what it should see if it was able to read the ISO in the same way that game consoles can:
Hopefully this explanation makes more sense.
An update on this: a piece of software called VGMToolkit contains an ISO extractor tool that is able to see and extract files from the second layer no problem:
Why no other software on the internet is capable of doing this is mind-boggling, as you'd think that this should be a default feature of every ISO manager, but I guess not!