dc:identifier id="uuid_id

Solo1959 · 05-07-2016, 05:03 PM

I have created several epubs in Calibre by converting from .txt, .docx, .odt, etc. I was having a problem with one of them so for the first time I right-clicked on the book to edit the book with Calibre. This is new to me.

When I looked at my book, I noticed this:

<dc:identifier id="uuid_id" opf:scheme="uuid">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier>
<dc:identifier opf:scheme="calibre">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier>

I don't know what those two lines mean. They must have been added during the conversion process. I deleted them form the book using the edit book function of Calibre, and the book reads exactly the same with no changes. I looked at my other epubs and noticed they all had similar lines.

What do these lines mean? What do they do? Is it safe to keep them in the book? Should I remove them from every book?

dwig · 05-07-2016, 05:20 PM

It is required in ePubs.

Check out: http://www.idpf.org/epub/20/spec/OPF...htm#Section2.1

theducks · 05-07-2016, 05:25 PM

Required.
But only if you are distributing them. (Or sync between devices)

It is like a vehicle VIN. The car runs fine, but attempted registration will hang

Solo1959 · 05-07-2016, 05:58 PM

Quote:

Originally Posted by Solo1959

I have created several epubs in Calibre by converting from .txt, .docx, .odt, etc. I was having a problem with one of them so for the first time I right-clicked on the book to edit the book with Calibre. This is new to me.

When I looked at my book, I noticed this:

<dc:identifier id="uuid_id" opf:scheme="uuid">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier>
<dc:identifier opf:scheme="calibre">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier>

I don't know what those two lines mean. They must have been added during the conversion process. I deleted them form the book using the edit book function of Calibre, and the book reads exactly the same with no changes. I looked at my other epubs and noticed they all had similar lines.

What do these lines mean? What do they do? Is it safe to keep them in the book? Should I remove them from every book?

Quote:

Originally Posted by dwig

It is required in ePubs.

Check out: http://www.idpf.org/epub/20/spec/OPF...htm#Section2.1

Quote:

Originally Posted by theducks

But only if you are distributing them. (Or sync between devices)

So I guess I should keep them in. They could be needed if I open the ebook in two different devices and want them to be synchronized between the two devices. In that case they would be required. I think I get it. It's a unique identifier so the devices know what ebook I am reading and this is more accurate than the title and author because it includes all of the other formatting information.

Thank you.

KevinH · 05-07-2016, 07:04 PM

These identifiers can also be involved in font obfuscation so if you make use of fonts, you may want to keep them.

BetterRed · 05-07-2016, 07:16 PM

Because viewers may make use of them it's probably best to leave the DC (Dublin Core) elements as is. If you're inclined, you can remove any non DC elements (e.g calibre custom column values) with the Modify plugin.

Added : does Calibre Companion use the uuid ?

BR

05-07-2016, 05:03 PM	#1
Solo1959 Connoisseur Posts: 73 Karma: 20000 Join Date: Feb 2011 Location: Florida Device: Kindle Oasis 2, Kindle Voyage, Kindle 5th gen, and many in the past	dc:identifier id="uuid_id I have created several epubs in Calibre by converting from .txt, .docx, .odt, etc. I was having a problem with one of them so for the first time I right-clicked on the book to edit the book with Calibre. This is new to me. When I looked at my book, I noticed this: <dc:identifier id="uuid_id" opf:scheme="uuid">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier> <dc:identifier opf:scheme="calibre">f272b91c-0459-4081-99a8-5cd790d5e618</dc:identifier> I don't know what those two lines mean. They must have been added during the conversion process. I deleted them form the book using the edit book function of Calibre, and the book reads exactly the same with no changes. I looked at my other epubs and noticed they all had similar lines. What do these lines mean? What do they do? Is it safe to keep them in the book? Should I remove them from every book?

05-07-2016, 07:16 PM	#6
BetterRed null operator (he/him) Posts: 22,018 Karma: 30277294 Join Date: Mar 2012 Location: Sydney Australia Device: none	Because viewers may make use of them it's probably best to leave the DC (Dublin Core) elements as is. If you're inclined, you can remove any non DC elements (e.g calibre custom column values) with the Modify plugin. Added : does Calibre Companion use the uuid ? BR Last edited by BetterRed; 05-07-2016 at 08:00 PM.

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05-07-2016, 05:20 PM	#2
dwig Wizard Posts: 1,613 Karma: 6718541 Join Date: Dec 2004 Location: Paradise (Key West, FL) Device: Current:Surface Go & Kindle 3 - Retired: DellV8p, Clie UX50, ...	It is required in ePubs. Check out: http://www.idpf.org/epub/20/spec/OPF...htm#Section2.1

05-07-2016, 05:25 PM	#3
theducks Well trained by Cats Posts: 31,267 Karma: 61916422 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	Required. But only if you are distributing them. (Or sync between devices) It is like a vehicle VIN. The car runs fine, but attempted registration will hang

05-07-2016, 07:04 PM	#5
KevinH Sigil Developer Posts: 9,072 Karma: 6361556 Join Date: Nov 2009 Device: many	These identifiers can also be involved in font obfuscation so if you make use of fonts, you may want to keep them.

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