Are cover.jpg and metadata.opf files included with Book.azw3 important?

[omareg94]

I've a book in the .azw3 extension. There are two files included with it in the same folder which are cover.jpg and metadata.opf.

Are the cover.jpg and metadata.opf embedded in the .azw3 file, so deleting them won't make loss of information?
Or, Should I keep these files, because they contain the cover and metadata of the book which aren't embedded in the .azw3 file?

Note: I use Kindle Previewer or Calibre for Microsoft Windows to open the .azw3 file.

[eschwartz]

Those contain backups of the metadata, and if you see them in the calibre library folders, don't touch them.

Best case scenario -- calibre recreates them.
Worst case scenario -- calibre loses metadata permanently. (You can always recreate it however you got the metadata in the first place. Metadata downloads/extract from ebook files -- mmm, fun.)


If those are in an exported folder, you can probably delete them. There is an option to not save them in the save to disk settings.

[omareg94]

Originally Posted by eschwartz

Those contain backups of the metadata, and if you see them in the calibre library folders, don't touch them.

Best case scenario -- calibre recreates them.
Worst case scenario -- calibre loses metadata permanently. (You can always recreate it however you got the metadata in the first place. Metadata downloads/extract from ebook files -- mmm, fun.)


If those are in an exported folder, you can probably delete them. There is an option to not save them in the save to disk settings.

Thanks a lot!

I've confirmed that cover.jpg and metadata.opf are embedded in the Book.azw3 file by copying the Book.azw3 file only to another PC and the result was that Calibre generated the two files again.

[eschwartz]

Well, some of it is. EPUB can embed arbitrary metadata types, AZW3 has a restricted list of only builtin metadata types -- series for example will not be retained.

[Mike L]

I'm not an expert in this area, so won't try to give a technical answer.

But I can tell you that, when I manually copy an AZW3 file to my Kindle, I never copy the JPG or OPF, and yet the correct cover and metadata still show up.

Mike

[eschwartz]

Then you have either saved to disk (and copied that) or used Embed Metadata.

[Mike L]

Then you have either saved to disk (and copied that) or used Embed Metadata.

Come again.

Save to disk? Well, I'm talking about files. Of course files are saved to disk at some point.

Embed metadata? Where would I do that?

Mike

[eschwartz]

Those are the names of the calibre tools, for exporting books from the library or for updating the actual library copies in-place. You can find their toolbar icons in Preferences ==> Toolbars.

calibre does not update the metadata in its own prolivate copies unless explicitly instructed.

[Mike L]

Originally Posted by eschwartz

Those are the names of the calibre tools, for exporting books from the library or for updating the actual library copies in-place. You can find their toolbar icons in Preferences ==> Toolbars.

We seem to be talking at cross purposes. I simply said that when I transfer books to my Kindle manually, the metadata and the cover art is visible on the device, even though I never explictitly transfer any other files.

I never mentioned Calibre.

Mike

[eschwartz]

metadata.opf and cover.jpg are files created by calibre. The issue at hand is why calibre needs them and if they are further needed.

If you wish to talk at cross purposes, you are more than welcome to do so.

[HarryT]

Originally Posted by eschwartz

metadata.opf and cover.jpg are files created by calibre. The issue at hand is why calibre needs them and if they are further needed.

That's true, of course, but had the OP been asking about Calibre he would have posted in the Calibre forum. The fact he posted in the Kindle forum would suggest that he's asking about files on his Kindle.

[eschwartz]

Err, I deduced from the fact that those files got mentioned at all, that calibre was involved???

I consider it perfectly natural for someone to ask a question about calibre and Kindles, in the Kindle forum. It could very well be that this turns out to be more about calibre than Kindles, or possibly about Kindles, tangentially related to calibre.

Since it is calibre that created those extra files on export (save-to-disk will save them in addition to the actual ebooks), I consider it entirely natural to assume that anyone discussing the copying of ebooks in the context of this thread, to be referring to calibre.


...since, after all, calibre is about Kindles (and many other things)...

Sheesh!

[Mike L]

metadata.opf and cover.jpg are files created by calibre. The issue at hand is why calibre needs them and if they are further needed.

Well,I don't want to labour this discussion longer than necessary, but the original question was whether cover images and meta data are embedded in AZW3 files. I simply stated that, when I copied an AZW3 file to my Kindle, I could see the cover images and meta data, which suggests that the answer to question was Yes.

That's all I'm saying: no more, no less.

Mike

[HarryT]

Originally Posted by Mike L

Well,I don't want to labour this discussion longer than necessary, but the original question was whether cover images and meta data are embedded in AZW3 files. I simply stated that, when I copied an AZW3 file to my Kindle, I could see the cover images and meta data, which suggests that the answer to question was Yes.

That's all I'm saying: no more, no less.

Mike

And you're absolutely right, Mike .