[Conversion Output] KFX Output

[stefano.sb]

Originally Posted by jhowell

The issue with cover thumbnails on Kindles also applies to AZW3 format and the "fix" for it is managed completely by calibre, not by this plugin. I suggest that you either start a new thread for your proposal or issue an enhancement request on the calibre bug tracker.

Perfect, thanks!

Stefano

[innocenat]

Hello,

This is not really a problem, but it's a little bit annoying and if you have time I would appreciate if you would look into it. I am not even sure if this would be your supported configuration.

Since I want the manga feature in Kindle, and I just refuse to connect my Kindle to the internet, I have been side-loading my manga. As you would know, I need to convert them to KFX for the manga feature.

So far my process has been:

1. Extract images file from KF8 file download from Amazon
2. Post-process the image with KCC using CBZ output. Extract the CBZ.
3. Use Kindle Create to create "Comics" type book. Import all images. Add table of contents.
4. Generate KPF from Kindle Create
5. Convert KPF to KFX using your plugin CLI interface

Everything works fine, except for the cover page of the KFX file. The first image in the book (the first page) will be display as cropped on actual Kindle (PPW3 7th gen). I have checked the KPF file with Kindle Previewer, and it displays fine. The cover display in library is okay, since I believed that's handled by calibre.

If you would want to look into this, I can send you the KPF file via email. It's definitely not in public domain. It's really not a big deal though.

[jhowell]

Originally Posted by innocenat

Everything works fine, except for the cover page of the KFX file. The first image in the book (the first page) will be display as cropped on actual Kindle (PPW3 7th gen). I have checked the KPF file with Kindle Previewer, and it displays fine. The cover display in library is okay, since I believed that's handled by calibre.

If you would want to look into this, I can send you the KPF file via email. It's definitely not in public domain. It's really not a big deal though.

I haven’t seen that sort of problem. I am willing to take a look at the KPF but it won’t be until late next week.

What firmware version is your Kindle running?

[innocenat]

Originally Posted by jhowell

I haven’t seen that sort of problem. I am willing to take a look at the KPF but it won’t be until late next week.

Was doing some more experiment and found it's probably not the problem with the plugin, sorry.

Cases when I saw cover broke during reading (fine in library view)

• KPF Manga side-loaded via calibre, with non 1.33:1 aspect ratio cover.

Cases where cover is fine:

• KPF Manga side-loaded via calibre, with 1.33:1 aspect ratio cover (not even the actual size, since I use KCC with PPW5 preset, but the device is still PPW3)
• KPF Manga side-loaded directly via USB (so no calibre amazon cover bug fix)
• All non-manga KFX

This just looks like the Kindle firmware wasn't designed to handle this usecase.

(Btw, I am running 5.14.2 on PPW3)

[innocenat]

After more investigation, it MAY be related to your plugin after all. I don't know enough about this, but here's what I find:

Case 1: KFX Manga. Cover Image A very large (1600x2560px). Same in Calibre and KFX => Library OK, Lock screen OK, first page cropped out.

Case 2: KFX Manga. Cover Image A large (1375x2200px). Same in calibre and KFX => All OK

Case 3: KFX Manga. Calibre Cover Image A. KFX Cover Image B. => All show image B, with the first page of the book show Image B as if it was Image A (Image B is smaller than A, so it's left-top aligned with blank space on the right and bottom).

Case 4: KFX Book. Calibre Cover Image A. KFX Cover Image B. => Same as above.

Case 5: Transfer KFX without calibre. No problem in any cases I tested.

I also checked and apparently KFX file sent by calibre has different size than KFX file on disk, so I am guessing calibre did something with the file during upload. I try to read the code, but I can't figure it out if it's calibre's doing or either KFX Input/Output plugin doing.

Here's my speculation:

The first page of KFX book (the cover) is displayed with the cover image in calibre library, but with the original stylesheet. Since the lock screen cover and cover thumbnail in library doesn't care about style, it displays correctly.

Something along the way probably also downsize the cover to 1375x2200px, triggering the problem for high-res cover image.

If it's EPUB to KFX conversion in calibre, no problem since the cover image is directly the same.

My workflow triggers this problem since the cover image in calibre is the original color image from KF8 but the one in KFX is B&W as processed by KCC.

Note: I have metadata management set to 'Automatic management' in calibre. Not sure if this is relevant.

It's really not a big deal at all (as it's okay in the most important place: library and lock screen), but if you can look into it I'd appreciate it nonetheless. Anyway, thank you for reading this far.

[jhowell]

Originally Posted by innocenat

After more investigation, it MAY be related to your plugin after all. I don't know enough about this, but here's what I find:
…
It's really not a big deal at all (as it's okay in the most important place: library and lock screen), but if you can look into it I'd appreciate it nonetheless. Anyway, thank you for reading this far.

Sending a book to a Kindle using calibre causes the metadata (including the cover) in the file sent to be updated to match the data in the calibre library. There may be a problem with that process which needs to be addressed.

It would help to know what sort of cropping you are seeing. Can you post a screenshot or describe it further?

I am currently traveling but will look into this when I get back later in the week.

[innocenat]

Originally Posted by jhowell

Sending a book to a Kindle using calibre causes the metadata (including the cover) in the file sent to be updated to match the data in the calibre library. There may be a problem with that process which needs to be addressed.

That's understandable. I don't know if it's the quirk of KFX format or not for the cover metadata to actually be used for displaying the first page (doesn't seems to be the case with other format?)

Originally Posted by jhowell

It would help to know what sort of cropping you are seeing. Can you post a screenshot or describe it further?

I put two sets of screenshots (calibre cover, KFX cover, and screenshot from my PPW3), one with cropping and one with letterbox here: https://imgur.com/a/ugJQMCD

I can send you the file needed (KFX and/or KPF, and the alt cover) to reproduce by email if you want (already have your email).

Originally Posted by jhowell

Thank you for looking into this.

[jhowell]

Originally Posted by innocenat

I put two sets of screenshots (calibre cover, KFX cover, and screenshot from my PPW3), one with cropping and one with letterbox here: https://imgur.com/a/ugJQMCD

I can send you the file needed (KFX and/or KPF, and the alt cover) to reproduce by email if you want (already have your email).

That’s for the screenshots. I will try to reproduce the problem when I get back later this week and will let you know if I need the files.

[jhowell]

Originally Posted by innocenat

Here's my speculation:

The first page of KFX book (the cover) is displayed with the cover image in calibre library, but with the original stylesheet. Since the lock screen cover and cover thumbnail in library doesn't care about style, it displays correctly.

You are correct. The part of this plugin that handles cover replacement only works for books with reflowable text. It fails to update the cover dimensions for fixed layout books, such as manga, causing the cover page to display incorrectly.

This will be fixed in the next release of the plugin.

[jhowell]

Version 1.60.0 - 09 Mar 2022

Detect Kindle Previewer versions up to 3.62.0.

Fix updating of the cover image for fixed layout comic or manga books. (Previous plugin versions produced a distorted or cropped cover page if the dimensions of the cover image were changed.)

[9acca9]

Im working on a Manjaro Linux.
After install wine, and the plugin, I'm getting this error after trying to convert.

calibre, version 5.38.0
ERROR: KFX conversion failed: <p><b>Cannot convert Caballeros</b><br><br><b>Conversion error:</b> Exception('Failed to locate wine within PATH = /app/bin:/usr/bin')</p>

But i have wine file in /usr/bin.

What can i do¿

[jhowell]

Originally Posted by 9acca9

Im working on a Manjaro Linux.
After install wine, and the plugin, I'm getting this error after trying to convert.

calibre, version 5.38.0
ERROR: KFX conversion failed: <p><b>Cannot convert Caballeros</b><br><br><b>Conversion error:</b> Exception('Failed to locate wine within PATH = /app/bin:/usr/bin')</p>

But i have wine file in /usr/bin.

What can i do¿

The most likely cause of that error is calibre being installed in some type of container that prevents it from being able to access Wine.

[pimprle]

Originally Posted by ssda

When i try to load a epub to kindle previewer i get this error.

"Error: This error will block the book from publishing. The error needs to be fixed in order to publish."
"Notice: This issue will not block the book from publishing and can be safely ignored as there will be no impact."
"Type","Description","Source File","Line Number","Text Preceding Warning or Error","Recommended Fix"
"Error","Kindle conversion has encountered an internal error.","","","","Our team needs to investigate this error in order to resolve. Please go to the KPR Help Menu and select the Send Feedback option to inform us of this issue. Please make sure you are signed in and we will provide you with more information within 3 business days. Thank you."

What can i do here? Also this thread helped me a lot. I'm grateful to you.

Hi guys, I've started to have the same problem recently trying to load ePUBs to KindlePreviewer, but I don't have a problem with opening The Frankenstein 😖
Did you come to any solution?
Thanks for any info

[pimprle]

Other thing is, that I'm able to create .mobi files from those ePUBs without any problems using kindlegen, but then I'm not able to open those .mobi files either in the KindlePreviewer.

[jhowell]

Originally Posted by pimprle

Hi guys, I've started to have the same problem recently trying to load ePUBs to KindlePreviewer, but I don't have a problem with opening The Frankenstein 😖
Did you come to any solution?
Thanks for any info

Some content in the source e-book file can cause conversion by the Kindle Previewer to fail. See the section "Dealing with Conversion Errors" in the first post in this thread for things you can try to find the cause of the conversion error and eliminate it.

Originally Posted by pimprle

Other thing is, that I'm able to create .mobi files from those ePUBs without any problems using kindlegen, but then I'm not able to open those .mobi files either in the KindlePreviewer.

That is typical. Kindlegen ignores some problems that cause the Kindle Previewer to fail.