[Conversion Output] KFX Output

[jhowell]

Originally Posted by njpig

This epub file sent to kindle via https://www.amazon.com/sendtokindle is not converted to kfx format. Anybody has clue on this?

That EPUB contains an interactive article from The Economist. It uses <video> elements that are not supported in Kindle ebooks.

[njpig]

Originally Posted by jhowell

That EPUB contains an interactive article from The Economist. It uses <video> elements that are not supported in Kindle ebooks.

Thanks a lot!

I found HTML and CSS Tags Supported in Kindle Format 8 here:
https://kdp.amazon.com/en_US/help/to...5R7N649LECKP7U

but did not find any information on kfx.

[jhowell]

Originally Posted by njpig

I found HTML and CSS Tags Supported in Kindle Format 8 here:
https://kdp.amazon.com/en_US/help/to...5R7N649LECKP7U

but did not find any information on kfx.

Amazon's documentation is very minimal. It does not refer directly to KFX format but uses the term "Enhanced Typesetting" instead. This page has a little bit of information:

Attributes and Tags Supported by Enhanced Typesetting

[texasnightowl]

I've moved this over to: https://www.mobileread.com/forums/sh...d.php?t=372579 since it's not only kfx related.

[JSWolf]

Have you tried calibre 9 and then see what happens? 7.26 is rather old and if you can run calibre 7.26, you should be able to run calibre 9.

[texasnightowl]

I have not...yet. I get tired of updating all the time. Once I have something setup and working, I usually coast with it. I've converted something like 10 other books so far today and only the 1 book has had any issues.

edit...I did just look at dates, and yeah, technically 7.26 is from Feb. 2025. Which means we went from 7.26 through ALL of 8 (17 releases) and now 6 releases of 9.x in 13 months. So yeah...when it's working, I tend to leave it alone.

[JSWolf]

Originally Posted by texasnightowl

I have not...yet. I get tired of updating all the time. Once I have something setup and working, I usually coast with it. I've converted something like 10 other books so far today and only the 1 book has had any issues.

edit...I did just look at dates, and yeah, technically 7.26 is from Feb. 2025. Which means we went from 7.26 through ALL of 8 (17 releases) and now 6 releases of 9.x in 13 months. So yeah...when it's working, I tend to leave it alone.

The way I look at it, when reporting an issue, I think it's a good idea to do so using the latest version of calibre you are able to run. Sometimes the issue could have been fixed or something changed.

[texasnightowl]

I've moved this over to: https://www.mobileread.com/forums/sh...d.php?t=372579 since it's not only kfx related.

[texasnightowl]

I've moved this over to: https://www.mobileread.com/forums/sh...d.php?t=372579 since it's not only kfx related.

[texasnightowl]

I've moved this over to: https://www.mobileread.com/forums/sh...d.php?t=372579 since it's not only kfx related.

[jhowell]

Originally Posted by texasnightowl

I've moved this over to: https://www.mobileread.com/forums/sh...d.php?t=372579 since it's not only kfx related.

Sorry for not responding sooner. I have been traveling and will look into the issue when I return home.

[texasnightowl]

Originally Posted by jhowell

Sorry for not responding sooner. I have been traveling and will look into the issue when I return home.

No apology necessary! I only posted about it this afternoon! Obviously I've figured out the problem isn't only kfx output related, but for sure if you have any suggestions I'm all ears!

[jhowell]

Version 2.19.0 - 01 Apr 2026

Detect Kindle Previewer versions up to 3.103.0.

Fix inability for the KFX Metadata Writer to change a file from a book (EBOK) to a personal document (PDOC) when the "Enable updating of all KFX metadata" plugin configuration option is enabled.

Add a warning during conversion to KFX that for best results page margins in the conversion options should be set to either "0.0" or "Unchanged".

[Mizuzu]

Okay so I genuinely can't figure out how to update the Cover on a Manga volume created through Kindle Create. I followed the process listed, used the command line to transform it into a KFX, then put it into calibre, added metadata and cover...but when I move it to my kindle, the cover thumbnail is the first page of the volume (with side white lines since it's not the aspect ratio of the screen) instead of using the cover I set it to be.

I tried enabling the update metadata settings on the plugin window, I tried the embed metadata button, and nothing seems to let me change the cover, doesn't matter what image I use, it always uses the first page and nothing else.