How to manage kepub.epub in Calibre

[davidfor]

Originally Posted by jxall

Even if I do understand the general sense of your answer, kepubs have been around for a while. AZW3 are Amazon-specific files just like KEPUBS are Kobo-specific files, so - considering that both formats have been around for many years now - why do AZW3 files have native support and KEPUBs don't?

Kobo is the 2nd most popular producer after all. And as I have shown, it is very useful for backup-restore / practical reasons to have Standard Books' native kepubs in Calibre library instead of epubs in my library.

Couldn't you try to normalize this situation through your plugins? (Allow Calibre to recognize .kepub.epub files just like .kepub files?

Honestly, because it would just be pointless. As I said, there is absolutely no use for kepubs outside the Kobo ereaders. Everything else can just treat them as an epub and they will work. Just download the epub version and know that when you send it to the device using the extended driver, it will be transformed. Or download the kepub version, add it as an epub, and again, the extended driver will handle that. And in either case, you won't have to worry about what other devices or apps do.

As to the plugins handling this, I don't think it would be possible. None of them work at the point where file name would be seen. They are working at a point after calibre has already decided on what format the book is. And something Kovid as said suggests that it wouldn't be very easy to fix elsewhere as calibre is working on the extension. I haven't looked, and I have no interest in looking as the solution is to easy: rename the file.

Of course, you could ask Standard Books to set the file name correctly so that you can add it to calibre properly.

[JSWolf]

Originally Posted by davidfor

Of course, you could ask Standard Books to set the file name correctly so that you can add it to calibre properly.

Standard Books needs to change their file type descriptions. They say ePub doesn't work on a Kobo and only KePub does. And then they say that ePub 3 is a more advanced format which in this case, it's not.

[jxall]

This free and open source software under the name of Ant Renamer (FossHub download page here) made it easy, fast and painless for me to bulk-rename dozens of .kepub.epub files to .kepub

I only had to throw all the .kepub.epub files in the program, then Actions > Change extension > [leave the field 'Replace extension with' completely blank] > GO - and the files got all renamed to .kepub in an instant.
(-- Even if there's an 'Undo' feature in the program, please note that Ant Renamer will rename the files in the original directory by default, so make a backup of the original files in case you are just experimenting --)

Afterwards I added the resulting .kepub files to Calibre and sent them to Kobo: they are properly formatted, as expected.

Thanks again for the insights and for the very useful help! Learning curve is getting less steep by the day!

[JSWolf]

Originally Posted by jxall

This free and open source software under the name of Ant Renamer (FossHub download page here) made it easy, fast and painless for me to bulk-rename dozens of .kepub.epub files to .kepub

I only had to throw all the .kepub.epub files in the program, then Actions > Change extension > [leave the field 'Replace extension with' completely blank] > GO - and the files got all renamed to .kepub in an instant.
(-- Even if there's an 'Undo' feature in the program, please note that Ant Renamer will rename the files in the original directory by default, so make a backup of the original files in case you are just experimenting --)

Afterwards I added the resulting .kepub files to Calibre and sent them to Kobo: they are properly formatted, as expected.

Thanks again for the insights and for the very useful help! Learning curve is getting less steep by the day!

You would be better off downloading the ePub and using the KoboTouchExtended driver to send them to your Kobo as KePub.

[jxall]

I would, but my test has shown that 'ld get a completely different formatting from the optimized kepub that Standard Ebooks provide and recommend.

That's why I asked if there was a way for Calibre to support .kepub.epub files out of the box. As things stand, manually editing the extension and adding the file to Calibre is the only possible way to preserve the optimized formatting while using Calibre.

[JSWolf]

Originally Posted by jxall

I would, but my test has shown that 'ld get a completely different formatting from the optimized kepub that Standard Ebooks provide and recommend.

That's why I asked if there was a way for Calibre to support .kepub.epub files out of the box. As things stand, manually editing the extension and adding the file to Calibre is the only possible way to preserve the optimized formatting while using Calibre.

Have you applied the patched to make the ePub and KePub font sizes the same?

Also, Standard EBOOKS lies. They say they have ePub and ePub3. Yet the ePub I downloaded is ePub3. Their CSS is rubbish.

The reason that the ePub and KePub are not the same is that they have no idea what they are doing. They should be making the KePub from the ePub source so anyone could do the same thing.

[PeterT]

Time for a chuckle. I was curious about how Standard eBooks formatted their content so started browsing their GitHub repository. In the tools/de/vendor/kobo_touch_extended directory you'll find kobo.py which is based on code from calibre.

The code has been restructured but appears to have the same function definitions and even the same comments in the code.

I have to wonder how the kepub format created by Standard eBooks compares to that by calibre. If my PC wasn't currently dead (I think it's power supply died and I can't get out today) I'd try taking one of their Epub formatted books and converting it in calibre.

[JSWolf]

Originally Posted by PeterT

Time for a chuckle. I was curious about how Standard eBooks formatted their content so started browsing their GitHub repository. In the tools/de/vendor/kobo_touch_extended directory you'll find kobo.py which is based on code from calibre.

The code has been restructured but appears to have the same function definitions and even the same comments in the code.

I have to wonder how the kepub format created by Standard eBooks compares to that by calibre. If my PC wasn't currently dead (I think it's power supply died and I can't get out today) I'd try taking one of their Epub formatted books and converting it in calibre.

They are different. The ePub is rubbish. The CSS is overly complicated. They do not understand "Keep it simple." Their ePub is ePub3 and their ePub3 is even worse. I don't get how they can mess things up as badly as they have.

[davidfor]

Originally Posted by jxall

I would, but my test has shown that 'ld get a completely different formatting from the optimized kepub that Standard Ebooks provide and recommend.

That's why I asked if there was a way for Calibre to support .kepub.epub files out of the box. As things stand, manually editing the extension and adding the file to Calibre is the only possible way to preserve the optimized formatting while using Calibre.

I just picked a book, https://standardebooks.org/ebooks/an...rton/star-born, and downloaded both the epub and kepub versions. I added the epub version to calibre and enabled the KoboTouchExtended driver. Then I sent it to the device. I put the kepub version directly on the device. Paging through each of them, I couldn't see any difference between them.

And comparing the code in the two versions, there is no significant differences between them. Which isn't surprising as the Python code they use add the spans is a direct rip from the KoboTouchExtended driver. Hell, as @PeterT stated, it is even called "kobo_touch_extended".

So, what are the differences you are seeing?

[jxall]

Originally Posted by davidfor

I just picked a book, https://standardebooks.org/ebooks/an...rton/star-born, and downloaded both the epub and kepub versions. I added the epub version to calibre and enabled the KoboTouchExtended driver. Then I sent it to the device. I put the kepub version directly on the device. Paging through each of them, I couldn't see any difference between them.

And comparing the code in the two versions, there is no significant differences between them. Which isn't surprising as the Python code they use add the spans is a direct rip from the KoboTouchExtended driver. Hell, as @PeterT stated, it is even called "kobo_touch_extended".

So, what are the differences you are seeing?

I replicated your test and you're right: there are no differences in this case.

I had performed my test with Great Expectations and differences were there and easy too see, though. I really don't know what to think!

[davidfor]

Originally Posted by jxall

I replicated your test and you're right: there are no differences in this case.

I had performed my test with Great Expectations and differences were there and easy too see, though. I really don't know what to think!

What are the differences? I tried what I did before with this book, and I don't see any differences. The frontmatter looks the same for both. The chapters are simple text and are laid out the same. The colophon page is probably the most complex in the book and I cannot see a difference between them.

Looking at the code in the books, the only noticeable difference is in the stylesheet with respect to hyphenation. The epub version has more options for turning on hyphenation than the downloaded kepub version. If you are use the centered option in the font settings on the device, it might produce a difference if words get split differently, but, I'm not seeing it.

[jxall]

I beg your pardon, the ebook that I had tested was David Copperfield.

I always set the Kobo to justify the text.

Here are a few examples of different formatting between the KE>(E)>KE and the K versions of the ebook (I have only checked the first dozen of pages):

• Preface to 1850 edition
• Preface to Charles Dickens edition
• Chapter 1

The differences involve line spacing and consequently the final number of lines per page (the kepub sento to Calibre and reconverted through KTE - aka KE>(E)>KE - produces thinner line spacing => more lines per page).

Of course I do believe in the lack of issues in Greatest Expectations, as I re-affirm that I didn't find any differences in Star Born just like you reported.

(It could well be that they got David Copperfield's kepub completely wrong - as JSWolf suggests - and that I'm just being a dumb idiot...)

[davidfor]

I'm not seeing any differences between the version direct from Standard Books and the epub version sent via the KoboTouchExtended driver. Attached are screenshots from my Clara HD of the same pages. There are no obvious differences. I also did the same on my Libra H2O with the same results.

From your screenshots, it looks like you might have different font settings for the two books. It looks like you have chosen the centred option for the justification, but, I'm not sure about other options. Or, are you using patches? Or the Modify CSS option in the driver?

In any case, I'm really not seeing any differences between the kepub download from the site, or using the epub and KoboTouchExtended driver.

[jxall]

I tried again the conversion - both by sending the kepub-epub and sending the epub through Calibre - and I always get the same result (files are different from the Standard Ebooks original kepub).
I even tried to disable/enable 'Clean up ePub markup' and 'Hyphenate files' options in Kobo Utilities: the result remains the same. Text is always justified (not centered).

My Kobo Clara is only a couple of weeks old, I didn't patch/modify the firmware in any way, nor I did touch CSS (I wouldn't even know how to do that).

Do you want me to send you the files so you can check them?

[JSWolf]

Originally Posted by jxall

I beg your pardon, the ebook that I had tested was David Copperfield.

I always set the Kobo to justify the text.

Here are a few examples of different formatting between the KE>(E)>KE and the K versions of the ebook (I have only checked the first dozen of pages):

• Preface to 1850 edition
• Preface to Charles Dickens edition
• Chapter 1

The differences involve line spacing and consequently the final number of lines per page (the kepub sento to Calibre and reconverted through KTE - aka KE>(E)>KE - produces thinner line spacing => more lines per page).

Of course I do believe in the lack of issues in Greatest Expectations, as I re-affirm that I didn't find any differences in Star Born just like you reported.

(It could well be that they got David Copperfield's kepub completely wrong - as JSWolf suggests - and that I'm just being a dumb idiot...)

There is a reason for some of the difference. I had a look at your photo for the 1850 Preface and I know exactly what's going on. With the ePub version, RMSDK is using kerning. With KePub, there is no kerning. So what's happening is that some of the characters in the KePub as not as close together and the title doesn't fit on one line.

Now you can fix this with options in the KoboTouchExtended driver. But as the KePub was made, you'd have to edit the CSS to ads in the options.

I have no idea of kepuify has such options to turn on kerning and hyphenation.