Newbie Question about Calibre and/or EPUB

[TheSmitty]

After much effort I got my entire Kindle library "downloaded and xfer with USB" to where I could add all the books (with appropriate plugin installed) into Calibre, YAY! So I think I have safe backups now.

I tried the conversion of one of them to EPUB and that worked but I noticed it produced several files, a epub, cover.jpg and a .opf file. I was expecting one self contained file but I guess I was wrong. Anyway, if I wanted to read the converted book on a different non-kindle device would I need to copy all those files? Still much to learn.

[Sirtel]

Originally Posted by TheSmitty

After much effort I got my entire Kindle library "downloaded and xfer with USB" to where I could add all the books (with appropriate plugin installed) into Calibre, YAY! So I think I have safe backups now.

I tried the conversion of one of them to EPUB and that worked but I noticed it produced several files, a epub, cover.jpg and a .opf file. I was expecting one self contained file but I guess I was wrong. Anyway, if I wanted to read the converted book on a different non-kindle device would I need to copy all those files? Still much to learn.

The best option would be to send the book to the device via Calibre interface, not the file explorer. But if you really want to just copy the file over, then the epub is sufficient. If you edited the book's metadata in Calibre and want the new metadata on your device, then you still have to use the Calibre GUI, or the option "save to disk -> save to disk in a single directory". The last option saves your book to your chosen location on your PC as a single file along with the edited metadata.

[dwig]

Originally Posted by TheSmitty

...if I wanted to read the converted book on a different non-kindle device would I need to copy all those files? Still much to learn.

No, you only need the ePub, mobi, or whatever file. They are self-contained files.

When calibre Adds a book to the library, it makes a copy of the book's cover, saving it as its own JPEG, and makes a copy of that book's metadata, which is saved in the .opf file. These two files are for calibre's use, though calibre's "export" function (aka Save to Disk) defaults to exporting the cover.jpg and the .opf file in addition to the selected ebook file(s). Personally, I've opted, in Preferences, to disable calibre's exporting the "extra" files.

By having an external cover.jpg, calibre saves a massive amount of time that would otherwise be necessary re-extracting the cover each and every time it displays a cover for each and every book. The .opf files serve as backups for calibre to use should library database repair or recovery be needed.