Book metadata

anthony.burton4 · 03-17-2017, 03:41 PM

I'm curious about a number of fields in the metadata of ebooks, I wonder if anyone could shed light on them.

MOBI's have a "Creator Software" field, together with Major Version, Minor Version and Build - anyone know to what this refers?

When I convert an epub to a mobi in calibre, the publication date is reset - is this always so, or is there a way to maintain original metadata?

If I convert a mobi to a mobi, the ASIN is altered to a 36 character string - to what does the new string refer?

Finally, some epubs I have, have calibre in the metadata: "<dc:contributor opf:role="bkp">calibre" I may have tweaked some stuff using calibre, but that's all, so not sure why is has it as "BooK Producer" - anyone enlighten me?

Cheers,
Tony

kovidgoyal · 03-17-2017, 11:51 PM

Creator software refers to the software used to create the MOBI. As does bkp in EPUB files.

When you "tweak" by which I assume you mean edit? AS far as I recall editing does not touch the bkp field, that is set to calibre if the EPUB is created by calibre ina conversion.

As for publication date being reset on conversion, I cannot reproduce that.

When converting MOBIs a randomnly generated ASIN (uuid) is inserted. The reasons for this I have explained many times before -- a bit of googling should find you the answer.

anthony.burton4 · 03-18-2017, 04:14 AM

Ah, many thanks for that Kovid

I am still puzzled by creator software though - if I convert an epub in calibre to a mobi, it is set to 201.1.2.33307. Is this the version of the library within Calibre that does the actual conversion work?

anthony.burton4 · 03-18-2017, 06:57 AM

OK - I see now that the 1.2.33307 is a kindlegen build.
Does that mean that 201 is the code for Calibre USING a kindlegen library?

The publication date thing - I note that in the EPUB file I tried, it was only stated as <dc:date> without an attribute indicating publication, which I guess is why it was ignored.

kovidgoyal · 03-18-2017, 09:09 AM

calibre does not use kindlegen. The version it inserts into that header is the version of kindlegen that was current at the time the MOBI output code was developed.

kovidgoyal · 03-18-2017, 09:10 AM

And note that those header fields are not jsut for kindlegen versions. amazon has various internal tools that it uses to generate MOBIs so there exist many MOBI files with versions that do not correspond to any kindlegen.

03-17-2017, 03:41 PM	#1
anthony.burton4 Connoisseur Posts: 64 Karma: 10 Join Date: Aug 2010 Device: iPhone	Book metadata I'm curious about a number of fields in the metadata of ebooks, I wonder if anyone could shed light on them. MOBI's have a "Creator Software" field, together with Major Version, Minor Version and Build - anyone know to what this refers? When I convert an epub to a mobi in calibre, the publication date is reset - is this always so, or is there a way to maintain original metadata? If I convert a mobi to a mobi, the ASIN is altered to a 36 character string - to what does the new string refer? Finally, some epubs I have, have calibre in the metadata: "<dc:contributor opf:role="bkp">calibre" I may have tweaked some stuff using calibre, but that's all, so not sure why is has it as "BooK Producer" - anyone enlighten me? Cheers, Tony

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03-17-2017, 11:51 PM	#2
kovidgoyal creator of calibre Posts: 43,853 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Creator software refers to the software used to create the MOBI. As does bkp in EPUB files. When you "tweak" by which I assume you mean edit? AS far as I recall editing does not touch the bkp field, that is set to calibre if the EPUB is created by calibre ina conversion. As for publication date being reset on conversion, I cannot reproduce that. When converting MOBIs a randomnly generated ASIN (uuid) is inserted. The reasons for this I have explained many times before -- a bit of googling should find you the answer.

03-18-2017, 04:14 AM	#3
anthony.burton4 Connoisseur Posts: 64 Karma: 10 Join Date: Aug 2010 Device: iPhone	Ah, many thanks for that Kovid I am still puzzled by creator software though - if I convert an epub in calibre to a mobi, it is set to 201.1.2.33307. Is this the version of the library within Calibre that does the actual conversion work?

03-18-2017, 06:57 AM	#4
anthony.burton4 Connoisseur Posts: 64 Karma: 10 Join Date: Aug 2010 Device: iPhone	OK - I see now that the 1.2.33307 is a kindlegen build. Does that mean that 201 is the code for Calibre USING a kindlegen library? The publication date thing - I note that in the EPUB file I tried, it was only stated as <dc:date> without an attribute indicating publication, which I guess is why it was ignored.

03-18-2017, 09:09 AM	#5
kovidgoyal creator of calibre Posts: 43,853 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	calibre does not use kindlegen. The version it inserts into that header is the version of kindlegen that was current at the time the MOBI output code was developed.

03-18-2017, 09:10 AM	#6
kovidgoyal creator of calibre Posts: 43,853 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	And note that those header fields are not jsut for kindlegen versions. amazon has various internal tools that it uses to generate MOBIs so there exist many MOBI files with versions that do not correspond to any kindlegen.