Any particular reason to create an ISO for local decrypted files?

[Perenista]

Let's say I have a decrypted DVD/Blu-ray in my SSD... the entire disc.

Meaning: VIDEO_TS or BDMV/etc. folders;

If there's some extra content in root, perhaps a software provided by the company.

For DVDs, I can use VLC, Media Player Classic or similar programs to open the VIDEO_TS folder.

For Blu-rays, probably a similar app exists.

Let's also assume I am storing these folders as data, in a BD-R. Or when I need to watch the original authoring, simply go back to my SSD.

The question is: why would someone put all these folders inside any ISO?

Isn't this a waste of time, like putting it inside a RAR?

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For preserving what I have:

What I usually do for both is this:

#1
Convert whatever the disc had for MKV/lossless; movie and bonus contents. Some stuff can't (or will break if I do, not all slideshows can be viewed that way)

#2
Remove from the decrypted folders what was already converted into MKV. For example, if the movie spends 90% of the disc, go to BDMV/STREAM and locate the m2ts, then delete it, to avoid duplicates. Same for extra features.

Most of the time, idea #2 works, but for some DVDs if you remove one single VOB, the disc will not start AT ALL, so no way to even see the menus; for a few DVDs, at least 1-2 GB need to be there, for the disc authoring to still work;

There was a case I removed probably 95% of it, just to check the menus (and probably some text pages), and it worked. So the DVD was reduced from 4-6 GB to less than 500 MB.

In one of the removals, only VLC opened the DVD, while MPC refused to do, and gave me a blank screen. Also, even if the players run the VIDEO_TS with a smaller size, of course we can't visit the removed content, otherwise the player will crash/return a black screen.

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Depending on the complexity of the DVD/Blu-ray, it's not advisable to remove anything AT ALL, even if we could. I noticed that for the Star Wars classic trilogy, and the bonus disc from Dungeons and Dragons (the animated series from 1983). Accessing these bonus contents from the many menus was a much better idea than doing from isolated MKVs + returning to the menus, otherwise we would be lost and not understand why they these specific videos were made in the first place.

[coricopat]

Originally Posted by Perenista

The question is: why would someone put all these folders inside any ISO?

Isn't this a waste of time, like putting it inside a RAR?

Especially if one places the files in a *new* ISO or UDF, than it makes sense at all, at least not from an archiving point of view, as these will be new filesystems that will not be exact duplicates of the originals.

When you want to make a true image, you must do so with some program that truly reads the medium block by block (like dd under Linux).

Whether or not this makes sense can of course be debated.
For example, some programs (I think MakeMKV, but don't call me liar if it remember wrongly) do for example "loose" the timestamps of the original files in the UDF image, even when making an non-decrypted backup of a BluRay.
Of course, you don't really need those.

Also, at least in theory one could imagine that a filesystem contains hidden data (e.g. blocks hat are on the medium, but never referenced by the filesystem), which you'd of course loose if you make a filebased copy, but not when you make a true image (which is not necessarily the same, if some program "re-creates" an image).
But again, it's rather unlikely that anyone ever did that, as such data would normally not be readable.