[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!


[update:]
So while I can get Kindle Previewer to open and preview (looks mostly correct), at least in this case, the exported MOBI does not render properly when side-loaded. Moreover KindleUnpack cannot split it into AZW3 & Mobi.

With the same ePub, Send To Kindle reports an error and the document it delivers is unreadable/scrambled up (it tries converting to reflowable format and sends 'failure' email).

Fixed layout ePub without positioned text (e.g. 'comics') are also converted to re-flowable AZW3 by Send To Kindle: you can 'highlight' or make notes on the images, for example. and with the apps, display 2 pages in landscape (but spreads will not join up). Maybe that's 'good enough' in some cases, but bottom line is that it's not as good as just consuming the ePub directly.

I do not know of a tool that can convert fixed layout ePub with embedded fonts and positioned text directly to AZW3 and have it render correctly when side-loaded. Or to PDF, for that matter.

So it goes!

[HowlerX]

Books converted to KFX (with the correct ASIN) using the command line and placed on the device do not allow the new Assistive Reader function to work--it's greyed out. While books converted to KFX within the Calibre GUI and Sent to Device will allow the Assistive Reader functionality to work. Any ideas why?

[jhowell]

Originally Posted by HowlerX

Books converted to KFX (with the correct ASIN) using the command line and placed on the device do not allow the new Assistive Reader function to work--it's greyed out. While books converted to KFX within the Calibre GUI and Sent to Device will allow the Assistive Reader functionality to work. Any ideas why?

No. I have not tried that. I will take a look at it next week.

[tomsem]

Originally Posted by HowlerX

Books converted to KFX (with the correct ASIN) using the command line and placed on the device do not allow the new Assistive Reader function to work--it's greyed out. While books converted to KFX within the Calibre GUI and Sent to Device will allow the Assistive Reader functionality to work. Any ideas why?

I think it is because KFX Output marks them as Personal Documents (PDOC) by default, whereas calibre marks them as Books (EBOK) by default.

Assistive Reader does not work with personal documents.

That said, when I experimented with this a couple of weeks ago, side loaded EBOK would not open due to 'Invalid ASIN' errors. I have not tried to figure out how to work around that.

[Elaine T]

Originally Posted by tomsem

I think it is because KFX Output marks them as Personal Documents (PDOC) by default, whereas calibre marks them as Books (EBOK) by default.

Assistive Reader does not work with personal documents.
.

There's an option somewhere, I think in Calibre's main conversion dialogues, to set KFX output to default to epub, not personal document.

[tomsem]

Originally Posted by Elaine T

There's an option somewhere, I think in Calibre's main conversion dialogues, to set KFX output to default to epub, not personal document.

Yes, I was referring to conversion of ePub to AZW3. The option is 'enable sharing' to make it PDOC, by default it is EBOK.

[jhowell]

Originally Posted by tomsem

Assistive Reader does not work with personal documents.

I had some time to test this and I can confirm that this is the case.

In order to get Assistive Reader to work with sideloaded books they must be created with CDETYPE=EBOK which mimics a book purchased or borrowed from Amazon. See the Usage section in the first post of this thread for instructions on how to do that when converting to KFX format.

[tomsem]

I suspect Assistive Reader does not work with AZW3 but have not tried it.

[tomsem]

From plugin notes:

The metadata and cover images in KFX files produced by this plugin can be updated to match the current data in the calibre library by a Metadata Writer Plugin that is built into this plugin. This is activated in calibre using the "Embed metadata" function...

Where do I find "Embed metadata" function?

[jhowell]

Originally Posted by tomsem

Where do I find "Embed metadata" function?

Embed metadata is one of the buttons you can add to your toolbar. Go to Preferences, Toolbars & menus.

[tomsem]

Originally Posted by jhowell

Embed metadata is one of the buttons you can add to your toolbar. Go to Preferences, Toolbars & menus.

Aha, thanks!