[Conversion Plugin] KFX Input

[yoshi]

I read the limitation mentioned in the first message of this thread:

> Limitations:
> The KFX format is undocumented and has changed over time. Books containing new or unknown features may fail to convert or result in incorrect content or formatting.

I appreciate that the creator of the KFX input plugin is updating it to address these issues.

I have a question: Will the latest version cover all the previous KFX files which could be converted in the past? If not, should I convert a KFX file as soon as the plugin can handle it?

[jhowell]

Originally Posted by yoshi

I have a question: Will the latest version cover all the previous KFX files which could be converted in the past?

I attempt to maintain compatibility with older versions of KFX. It is possible that I could make a mistake but if so I will correct the problem once it is reported.

Originally Posted by yoshi

If not, should I convert a KFX file as soon as the plugin can handle it?

I personally would remove DRM and convert files as I acquire them, just in case.

[yoshi]

I got the AZW3 (Download & transfer via USB) and KFX (Kindle for PC 2.4.0) versions of "Quiz Game Book: Trivia Questions With Answers" from Amazon Japan and converted them to EPUB using "KindleUnpack" and "From KFX". The JPEGs of the cover page differ significantly:

[AZW3]
File size: 122,376 bytes
Image size: 1439 x 2290 pixels
JPEG compression: Quality 40
Number of colors: 41,390

[KFX]
File size: 297,173 bytes
Image size: 1207 x 1920 pixels
JPEG compression: Quality 100
Number of colors: 9,992

The picture quality from the AZW3 file looks better than from the KFX file. Is it possible to restore the original JPEGs?

Otherwise, is it possible to reduce the JPEG compression quality to reduce the file size? The file size becomes less than half if 100% is changed to 85%.

[jhowell]

Originally Posted by yoshi

I got the AZW3 (Download & transfer via USB) and KFX (Kindle for PC 2.4.0) versions of "Quiz Game Book: Trivia Questions With Answers" from Amazon Japan and converted them to EPUB using "KindleUnpack" and "From KFX". The JPEGs of the cover page differ significantly:

Amazon uses different image sizes and compression levels for the same book when delivered in different formats or to different device classes.

The cover image file you get using From KFX is whatever is contained within the KFX file you converted.

Originally Posted by yoshi

The picture quality from the AZW3 file looks better than from the KFX file. Is it possible to restore the original JPEGs?

Not using this plugin.

You can change the cover image using calibre if you find one that you like better.

Originally Posted by yoshi

Otherwise, is it possible to reduce the JPEG compression quality to reduce the file size? The file size becomes less than half if 100% is changed to 85%.

If you want that done it is up to you to accomplish it using something other than this plugin.

[yoshi]

Thank you for your reply.

It seems that the graphic files embedded in AZW3 and KFX formats can differ for the same book. Your plugin extracts the original files. Is my understanding correct?

I can edit EPUB files myself and will do so when necessary.

[jhowell]

Originally Posted by yoshi

It seems that the graphic files embedded in AZW3 and KFX formats can differ for the same book.

Yes, definitely. It can even differ for the same format delivered to different devices.

Originally Posted by yoshi

Your plugin extracts the original files. Is my understanding correct?

It extracts whatever was present in KFX format. That is likely different from the original files provided by the book publisher.

[yoshi]

EBUB-based KFX files can be opened in Calibre, but PDF-based ones can't.
Is this an issue with Calibre?

[jhowell]

Originally Posted by yoshi

EBUB-based KFX files can be opened in Calibre, but PDF-based ones can't.
Is this an issue with Calibre?

By default the KFX Input plugin blocks conversion of print replica books to EPUB because the results are generally inferior to using From KFX to produce PDF. Because viewing in calibre requires conversion to EPUB that will not work for those books.