[Conversion Output] KFX Output

[jhowell]

Originally Posted by toadclones

The page list works properly in the calibre reader but not on my kindle after the KFX conversion. I see here you say that it should work, but that was back in 2022. Does it still work? or are these pages not configured properly?

Because Amazon's Kindle Previewer uses EPUB as its source format the KFX Output plugin converts whatever input format you supply to EPUB before passing it to the Previewer. That process is done using code that is part of calibre itself, not this plugin.

If you take your scrambled.epub file and use calibre to convert it from EPUB to EPUB (with the default output option of version 2) you will find that the page numbers list is stripped from the book. Since that is what is happening as the first step in conversion to KFX the page numbers will be missing from the converted book.

I don't know why calibre is stripping the page number list in EPUB-to-EPUB conversion. It seems to be a bug. If you want to pursue that further you can open a calibre bug report based on the results obtained when doing EPUB-TO-EPUB conversion of your book.

Also, if do an EPUB-to-EPUB conversion of that book and choose EPUB version 3 as the output format the result will retain the page number list, but many of the links become broken in that case. That appears to be caused by a different calibre conversion bug.

If you want to bypass this problem and convert your book with page numbers intact I suggest that you use the plugin's Command Line Interface (CLI), documented in the first post of this thread. Using that bypasses calibre's conversion software and its page list related bugs.

[toadclones]

Originally Posted by jhowell

I don't know why calibre is stripping the page number list in EPUB-to-EPUB conversion. It seems to be a bug. If you want to pursue that further you can open a calibre bug report based on the results obtained when doing EPUB-TO-EPUB conversion of your book.

It's weird, even if you add the nav.xhtml to the spine calibre will still remove the properties="nav" from the nav entry in the manifest so the plugin doesn't see it.

In any case, using the CLI worked perfectly. Thanks for the help!

[tomsem]

Nothing to do with the plugin, but having this issue with Kindle Previewer and do not know how to fix this:

E34002: Please specify the Original-resolution metadata value in the format WIDTH x HEIGHT.

This is with a fixed layout ePub, with 'positioned text'. It passes ePubCheck without errors or warnings (following 2 small edits).

Trying to convert to AZW3, either with Kindle Previewer or maybe Send to Kindle to see how it turns out. Though in the end Apple Books will be a better reading experience for these.

[jhowell]

Originally Posted by tomsem

Nothing to do with the plugin, but having this issue with Kindle Previewer and do not know how to fix this:

E34002: Please specify the Original-resolution metadata value in the format WIDTH x HEIGHT.

From the Amazon Kindle Publishing Guidelines version 2025.1 section 13 (Creating Fixed-Layout Books Without Pop-Ups):

<meta name="original-resolution" content="1024x600"/>

Required. Identifies the original design resolution of the content (“1024x600” is only an example). The pixel dimensions can have any positive integer value. These values must be in proportion to the overall aspect ratio of the original content.

That needs to be present in the OPF of the EPUB.

[tomsem]

Originally Posted by jhowell

From the Amazon Kindle Publishing Guidelines version 2025.1 section 13 (Creating Fixed-Layout Books Without Pop-Ups):



That needs to be present in the OPF of the EPUB.

Thanks much!