[jhowell]

Originally Posted by Karellen

mobi or kfz (which calibre does not edit. why?)

The calibre editor is primarily an EPUB 2 editor. KF8 (azw3) format has basically the same content as EPUB 2 but packaged differently so it is not a big stretch to support that also.

MOBI is very similar to KF8 but is based on the ancient HTML 3 standard. I don't know why it isn't supported, perhaps because it is such an outdated format.

KFX on the other hand isn't based on HTML, but is a very proprietary Amazon format. Editing that would be next to impossible due to a lack of any documentation of how it works.

Originally Posted by Karellen

1. Why, when converting from any other format to epub, is so much excess and useless code added? Looking through the css file, everything is "calibre_1, calibre_2" etc, and there can be upto 50 code styles, and most of them are the same or similar anyway.

Calibre's conversion process is designed to be able to the modify formatting of books. As part of that it regenerates CSS and flattens class definitions. Personally, I would prefer to have an option to disable that and leave the original formatting intact as much as possible.

Originally Posted by Karellen

Then there is an excess of <span> throughout each xhtml page. There are even <spans> on the spaces between words. I can't imagine the original book was built this way. So why is there so much garbage code after conversion?

I haven't seen spans on spaces. I suspect that may have to do with the source of the book. I have heard that Kobo has a Kepub format which is known for having spans around everything.

Originally Posted by Karellen

2. When using DeDRM, why does it automatically convert to mobi? How can you change it to convert directly to epub?

If you are getting books from Kindle for PC/Mac it tends to use the extension .azw regardless of the actual format of the book. DeDRM detects and sets the actual book format. You may be seeing MOBI because that was the actual format of the book.

There is an option in calibre to automatically convert books to another format upon import. (Preferences, Adding Books, Adding actions, Automatically convert added books to the preferred output format.) You may want to check that you have not enabled this by mistake.

Originally Posted by Karellen

Is there any way, or better plugins to use that avoids the above?

The KindleUnpack plugin can unpack from KF8 (azw3) format to EPUB without going though the calibre conversion process. This results in an EPUB that matches the original source file provided by the publisher as closely as possible.