[Conversion Plugin] KFX Input

[LessPaul]

Wrong thread.

[jhowell]

Version 1.44.0 - 04 Oct 2021

Fix optimization that was incorrectly removing nested div elements in some rare cases.

[Xari04]

Hello, sorry if this doesn't belong here first of all. I'm having troubles installing the plugin on Calibre, saying there's no top level _init_.py file. I should mention though that when I download the zip folder, for some reason safari is immediately decompressing it into a regular folder so I tried compressing it into a zip file to instal it on Calibre.

Here's the full error:

calibre, version 5.29.0
ERROR: Unhandled exception: <b>InvalidPlugin</b>:The plugin in '/Users/diego/Downloads/KFX Input.zip' is invalid. It does not contain a top-level __init__.py file

calibre 5.29 embedded-python: True is64bit: True
macOS-10.16-x86_64-i386-64bit Darwin ('64bit', '')
('Darwin', '20.6.0', 'Darwin Kernel Version 20.6.0: Mon Aug 30 06:12:21 PDT 2021; root:xnu-7195.141.6~3/RELEASE_X86_64')
Python 3.8.5
OSX: ('10.16', ('', '', ''), 'x86_64')
Interface language: None
Successfully initialized third party plugins: DeDRM (7, 2, 1) && Obok DeDRM (7, 2, 1)
Traceback (most recent call last):
File "calibre/gui2/preferences/plugins.py", line 327, in add_plugin
File "calibre/customize/ui.py", line 477, in add_plugin
File "calibre/customize/ui.py", line 65, in load_plugin
File "calibre/customize/zipplugin.py", line 284, in load
File "calibre/customize/zipplugin.py", line 379, in _locate_code
calibre.customize.InvalidPlugin: The plugin in '/Users/diego/Downloads/KFX Input.zip' is invalid. It does not contain a top-level __init__.py file

[jhowell]

Originally Posted by Xari04

Hello, sorry if this doesn't belong here first of all. I'm having troubles installing the plugin on Calibre, saying there's no top level _init_.py file. I should mention though that when I download the zip folder, for some reason safari is immediately decompressing it into a regular folder so I tried compressing it into a zip file to instal it on Calibre.

It appears that you did not re-zip the plugin correctly.

You can download and install plugins from the calibre user interface without using Safari. Go to Preferences, Plugins, Get new plugins.

[Xari04]

That was the quickest and dumbest fix ever, it's all working now. Thanks a lot!

[Lief]

Hello, thank you for this plugin and the instruction to avoid KFX on Kindle desktop updated app (both work and I like to still be able to convert my ebook to epub when I need it).
Since I discovered this thread only in the last few months I don't really know the history, do you plan to support kindle app after 1.26? Do you know why it does not work right now or it's a mistery and the work done until now it's not of any help for KFX past 1.26 version?
Can you try to explain what does not work right now?
Is there any github or anything like that repository for this plugin?

Thank you.

[jhowell]

Originally Posted by Lief

Since I discovered this thread only in the last few months I don't really know the history, do you plan to support kindle app after 1.26?
Do you know why it does not work right now or it's a mistery and the work done until now it's not of any help for KFX past 1.26 version?
Can you try to explain what does not work right now?

All books in KFX format have DRM. Removal of DRM is not performed by the KFX Input plugin. It is handled by the DeDRM plugin available from Apprentice Harper's GitHub.

Amazon has been aggressive in introducing new forms of KFX DRM whenever it has been broken. They have also implemented extra unused KFX DRM variants that can be immediately enabled without the need to roll out new software.

Kindle for PC versions 1.27 and newer use a KFX DRM scheme that the DeDRM plugin does not currently support. It is unclear whether or not anyone is working on correcting this. You would need to ask at Apprentice Harper's GitHub for updates.

Originally Posted by Lief

Is there any github or anything like that repository for this plugin?

There is no GitHub repository for the KFX Input plugin. However there is one for the DeDRM plugin, where the current problem lies.

[Lief]

Originally Posted by jhowell

All books in KFX format have DRM. Removal of DRM is not performed by the KFX Input plugin. It is handled by the DeDRM plugin available from Apprentice Harper's GitHub.

Amazon has been aggressive in introducing new forms of KFX DRM whenever it has been broken. They have also implemented extra unused KFX DRM variants that can be immediately enabled without the need to roll out new software.

Kindle for PC versions 1.27 and newer use a KFX DRM scheme that the DeDRM plugin does not currently support. It is unclear whether or not anyone is working on correcting this. You would need to ask at Apprentice Harper's GitHub for updates.



There is no GitHub repository for the KFX Input plugin. However there is one for the DeDRM plugin, where the current problem lies.

Ok I did not know that (I just understand that it was a not documented new format I did not understand that it force drm that's why I asked here). I checked my own ebook (published without the drm) and it indeed now use drm, I wrote to amazon to complain about it, I don't want my own ebook to use drm when I decided to avoid drm.
So if I understand it right this plugin actually convert KFX format if it is without drm (like it was in Kindle until 1.26).

So there is no difference between ebooks published with and without drm on amazon right now?

[jhowell]

Originally Posted by Lief

So if I understand it right this plugin actually convert KFX format if it is without drm (like it was in Kindle until 1.26).

Yes. This plugin should be able to convert KFX files from newer versions of Kindle for PC and from e-ink Kindle devices as long as DRM has been removed first.

There have been some minor changes to KFX format over time but I have been able to keep up with them by using Amazon's Kindle Previewer, which produces a variant of KFX format (KPF) without DFM.

Originally Posted by Lief

So there is no difference between ebooks published with and without drm on amazon right now?

That is not quite true.

First, most books can be obtained in the older MOBI7 and KF8 formats by various means, such as using the Download & Transfer via USB option available to e-ink Kindle owners on Amazon's web site. Those will not have DRM if the publisher has requested that.

Second, although books in KFX format will have DRM in either case, there is actually a difference in the DRM used depending on whether or not the publisher has requested DRM.

In the case where no DRM was requested, the KFX DRM used protects the book against decryption by third-party tools, but does not lock the book to a particular device. This allows the copying of the book between Kindle devices, even those registered to different users.

[jamminjames]

@jhowell, when I use your Calibre KFX Input plugin, no matter what Calibre settings I try (including using Tablet for the output size), the resulting EPUB is much smaller than the original created via Kindle Textbook Creator. How can I avoid this downsizing? Thanks for any help!

[jhowell]

Originally Posted by jamminjames

@jhowell, when I use your Calibre KFX Input plugin, no matter what Calibre settings I try (including using Tablet for the output size), the resulting EPUB is much smaller than the original created via Kindle Textbook Creator. How can I avoid this downsizing? Thanks for any help!

What are you trying to accomplish by this conversion?

Conversion to EPUB via calibre is designed for reflowable books. Using a print replica KPF file as the input is not going to yield good results. In this case the KFX Input plugin will rasterize the PDF into a series of JPEG files with one page of content each. The resulting file won't be much good for anything.

Side note: Although the results should be pretty much the same for a print replica book, Kindle Textbook Creator has been superseded by Kindle Create. Both take a PDF file and produce a print replica KPF file suitable for publishing on Amazon.

[hollowpoint]

Troubles importing KFX from new PW5 to Calibre. Latest Calibre 5.31.1, DeDRM 7.2.1, Win11.

To enable importing KFX from new PW5 to Calibre, I did the following:

1. Install DeDRM and configure with Kindle serial.
2. Go to Preferences > Tweaks > Plugin Tweaks, and add the following configuration line: kfx_input_set_format_virtual = False

Result: Books are imported as KFX-ZIP. But are still locked.

Is this the current state of KFX, it cannot be successfully imported and read in Calibre, unless previously decrypted?

[jhowell]

Originally Posted by hollowpoint

Is this the current state of KFX, it cannot be successfully imported and read in Calibre, unless previously decrypted?

Amazon has been very aggressive in updating the DRM used for KFX format. Each time that a solution for KFX DRM has been added to the DeDRM plugin Amazon has blocked it by quickly switching to a new DRM scheme.

At this time DRM removal for KFX books on Kindle devices only works if the device is running firmware version 5.12.1 (released in 2019) or earlier.

[hollowpoint]

@jhowell, thanks for that, not to mention your work on these plugins.

So for Kindle, I now have only PW5, it sounds like KFX import from e-ink is off the table. I'm moving off Amazon platform entirely to use mainly Kobo and other epub sources, but still have about 20 books in KFX I'd like to convert to AZW3, import to Calibre and liberate.

If I go with installing the older Kindle-for-PC, which version is the best option for completing this process? I have v1.24.51068 that I had archived locally, but it won't run right on Win11 (installs, but then locks in this odd loop when you get to the Kindle registration screen). More than happy to install an older Kindle-for-PC version and simply disable KFX, then import as AZW3 and go from there. Or I can still install 1.24 on another Win10 PC, just for the purposes of format conversion > import to Calibre. I'll do whatever gets this done with the least amount of hair-pulling.

[jhowell]

Originally Posted by hollowpoint

So for Kindle, I now have only PW5, it sounds like KFX import from e-ink is off the table. I'm moving off Amazon platform entirely to use mainly Kobo and other epub sources, but still have about 20 books in KFX I'd like to convert to AZW3, import to Calibre and liberate.

Because you have a Kindle device registered to your Amazon account you have the option to download books directly from Amazon’s website. That is by far the easiest procedure because it will never give you KFX format and it avoids Kindle for PC entirely.