Kobo Bug thread

[jbennion]

@arspr, you might be on to something here. I have ALSO seen the errors you have mentioned. While I actually don't have those fonts on my Kobo, I note that this is default Kindle font (is it not?), and so it makes me wonder if this is either a Calibre conversion bug or something I could fix in a custom routine when converting MOBI files to EBPUB (with the enhanced driver no longer supported, I am not sending any more KePUBs to my Kobo).

If so, that may also explain the weird path? Maybe it's a Kindle path? Maybe we need a routine or option to strip that out when converting?

UPDATE: I used Sigil to comment that out in the Styles.css section and I am not seeing the problem anymore. I think we've found the problem!

[davidfor]

Originally Posted by jbennion

(with the enhanced driver no longer supported, I am not sending any more KePUBs to my Kobo)

So the developer stopping updating it stopped if from working? But, that doesn't matter. While the original developer has stepped back from the driver, others have stepped in and made any necessary updates. Not that there has been much need.

The extended driver isn't going away. If you want to use kepubs, use them.

[arspr]

@jbennion. Please, go to the dedicated thread in Calibre > Conversion (moved from Editor by BetterRed) and provide info about your Calibre settings while doing the original MOBI to EPUB conversion.

I mean, yes, we are completely sure Kobo ACCESS has a rendering bug (another one more) about handling those missing fonts. But your case might also show a Calibre conversion issue. Please provide all the info you can about HOW you've done the conversion (which settings you have used), and specially check (confirm or deny) what jackie_w is suggesting which might be a good guess given the device info you have posted in your profile (that you own a Sony PRS-650).

OTOH, be careful while hunting book bugs with Sigil. Sigil rebuilds the whole book, (and it completely modifies its internal structure), just when you open it, so Sigil *might* hide the original issue. Calibre Editor is much better suited for this task because it does not modify the book in any way unless you explicitly perform actions with it, (well, at least, it doesn't perform any modification in the book if you deactivate "metadata sync" and "auto-beautify files on opening").

[Dryhte]

New bug in 3.15:

(at least on Kobo Aura)

Unable to disable 'pinch-to-zoom', with the additional bad effect of popping up the 'magnifying glass' when you don't expect it, and it can't be dismissed until you've zoomed in/out somewhat.

Highly annoying, I might add. Fix this, Kobo! pretty pretty please?

[Nick Payne]

I updated my Aura HD to 3.15.0 last week - was previously running 3.13.1. Two new problems that I haven't encountered with previous F/W I've had installed:

1. When I want to add an annotation, the target area for positioning my finger on a word is much smaller than previously. About half the time when I attempt to add an annotation, I now accidentally get either a page forward or page back, or if I'm close enough to the centre of the page, the top and bottom menus appear. This problem very rarely happened with previous releases.

2. When I do add an annotation, I can still dimly see the annotation popup menu on screen after it has been dismissed. I've changed screen refresh from where I previously had it at the default of every six pages to every three pages, so that the ghost goes away more rapidly. I see the same problem if I bring up the brightness dialog and press at various points on the slider - ghost images of the circle indicating the brightness setting remain at the previous locations. Interestingly, when I dismiss the dialog, the ghost images of the circle remain visible but not any part of the dialog itself nor the actual real location of the circle.

[davidfor]

Originally Posted by Nick Payne

I updated my Aura HD to 3.15.0 last week - was previously running 3.13.1. Two new problems that I haven't encountered with previous F/W I've had installed:

1. When I want to add an annotation, the target area for positioning my finger on a word is much smaller than previously. About half the time when I attempt to add an annotation, I now accidentally get either a page forward or page back, or if I'm close enough to the centre of the page, the top and bottom menus appear. This problem very rarely happened with previous releases.

This is probably what is being discussed in Long presses barely work in 3.15. It seems to have hit some devices and others are having no problems.

2. When I do add an annotation, I can still dimly see the annotation popup menu on screen after it has been dismissed. I've changed screen refresh from where I previously had it at the default of every six pages to every three pages, so that the ghost goes away more rapidly. I see the same problem if I bring up the brightness dialog and press at various points on the slider - ghost images of the circle indicating the brightness setting remain at the previous locations. Interestingly, when I dismiss the dialog, the ghost images of the circle remain visible but not any part of the dialog itself nor the actual real location of the circle.

This has been discussed. A workaround is described here.

[Nick Payne]

Originally Posted by davidfor

This has been discussed. A workaround is described here.

Thanks. I added that ghosting fix setting to the "Kobo eReader.conf" file and rebooted the reader, but it hasn't fixed the ghosting problem, which is still there.

[freekobo]

Originally Posted by Dryhte

New bug in 3.15:

(at least on Kobo Aura)

Unable to disable 'pinch-to-zoom', with the additional bad effect of popping up the 'magnifying glass' when you don't expect it, and it can't be dismissed until you've zoomed in/out somewhat.

Highly annoying, I might add. Fix this, Kobo! pretty pretty please?

FYI there is a patch available here to fix this;
https://www.mobileread.com/forums/sho...&postcount=111

[beedaddy]

After some time I'm back in the Kobo universe, now with the Glo HD.
But it didn't take long to notice some odd things with their firmware (3.15.0).

First, while reading the German newspaper "Die Zeit" (epub) on the Kobo, I noticed that the Glo HD didn't do any hyphenation. The text was left-aligned. For me, this is odd. Any other eReaders I've used so far use hyphenation in that case.

Then, I tried to change the text-orientation to "justify". This was not possible. It just stayed left-aligned. I had to comment out the line in the CSS:

div.article {
    margin-left: 1em;
    margin-right: 1em;
    /*text-align: left;*/
}

After that, I was able to change the text orientation. And using justify, the device even uses hyphenation.

But, there are quite a lot eBooks (again, epub!) with this problem and some of them with DRM...

Since these problems don't occur on other EPUB-based-eReaders (like the Tolino Vision), I guess this is not an Adobe SDK-related problem. So... Kobo could fix it, right?

[cramoisi]

Hi !
I don’t know if it is known but in the epub on 3.15.0 , when a word with double ’t’ or double ‘f’ is hyphenated at the end of the page, the letter is present 3 times (in french) :

end of page 1 : Il suf-
beginning of page 2 : -ffisait

I checked the book, the letter is only present twice (which is correct). Until now i have only seen that for ’t’ and ‘f’...

[panickros]

Hi,

New (possible) bug in 3.16.0 :

I am using Kobo Glo HD with 3.16.0 firmware installed today.
When opening KEPUB file which is converted from cbz,
after first page(cover), it goes black with/without white border.

I can call menu, and can go back and forth, only the contents are gone black.

I don't think it is anything related with JPEG rendering engine,
because I can read normally the cbz file which was the original source for problematic KEPUB.

I can reproduce the situation 100% by converting cbz into kepub with calibre.
And those files made no problem with older firmware.


However, there are two points you might want to consider.

Firstly, I use calibre on my Korean version of Windows 7.
Maybe there can be some issues with code-page, encoding, or character-set of the original cbz file. To prevent any problem, I do not to use any Korean character file name for my cbz, regardless cbz file with Korean file name actually makes no problem.
But, maybe, there can be tiny possibility that this problem is originated from Korean version of Windows.


Secondly, I applied some optional tweak to add .fxl.kepub.epub extension when calibre transfers files to Kobo.

"Proper way to convert CBZ-to KEPUB with calibre" (Korean)
http://www.alphafactory.co.kr/post/2...-with-calibre/

I disabled the tweak, but it shows same results, black contents.
Changing file name also doesn't work either.



I am looking for someone who is brave enough to reproduce this with their kobo reader, and confirm whether it is because my own problem, or some new bug with the new firmware.


Thanks.

[davidfor]

Unfortunately, I can confirm this. But, it seems to only happen with PNG images that have a reduced palette.

I have a test kepub (from DNSB I think) with lots of different things in it. This has six versions of the same image in it. The only one that has a problem is the grayscale PNG with 16 levels. Experimenting with the calibre conversion from a CBR to kepub, if I turn of the image processing, everything is OK. If I have this on and convert to PNG, the images are black.

So, the workaround is to either turn the comic processing off, or convert to JPG.

I have reported this to Kobo with my test case.

[compurandom]

Originally Posted by davidfor

The only one that has a problem is the grayscale PNG with 16 levels.

This reminds me... I think there is a minor bug in the image display code that also affects pdf's.

I think there is a quantization error in converting grey scale in general to what the eink screen needs. At a guess without any experimentation, it feels like they are doing a direct threshold conversion without any dithering. The result is that images with even distribution of colors look fine, but in a few edge cases some strange artifacts show up.

For example, I have a pdf that is probably from a scanned document. When I tried to read it on my kobo, there was a huge smear down the middle that looked like something was stuck to the scanner and made the document unreadable. When I view the pdf on my laptop, I can see the smear, but it is very faint.

I checked other documents from the same source, and they had the smear, but it was a slightly different shade of grey that did not render on the kobo and the document was readable.

My guess is that the smear sometimes falls into the same bucket as the text due to the way the colors are quantized. I didn't think about it much at the time, I should try to generate a test case.

[cramoisi]

Originally Posted by cramoisi

Hi !
I don’t know if it is known but in the epub on 3.15.0 , when a word with double ’t’ or double ‘f’ is hyphenated at the end of the page, the letter is present 3 times (in french) :

end of page 1 : Il suf-
beginning of page 2 : -ffisait

I checked the book, the letter is only present twice (which is correct). Until now i have only seen that for ’t’ and ‘f’...

This behavior has been corrected with 3.16.0 on my H20 (sideloaded mark 4 firmware)

[panickros]

Originally Posted by davidfor

Unfortunately, I can confirm this. But, it seems to only happen with PNG images that have a reduced palette.
.........
So, the workaround is to either turn the comic processing off, or convert to JPG.
.........

Thank you very much davidfor!!

I am not familiar with calibre, so I just thought it just reduces the size of JPEG when converting CBZ to KEPUB. (It actually converts images to PNG)

Anyway, I tested very same cbz file with comic processing off, and it works like a charm.

I hope KOBO solves this bug as soon as possible.