Kepub for technical books not working properly on Kobo Aura one - Page 2

PeterT · 06-28-2017, 08:43 PM

If the issue is related to the TOC then the only thing that would help is simplifying it!

Sent from my Nexus 7 using Tapatalk

JSWolf · 07-02-2017, 10:24 PM

If this is an ePub from Kobo and you are downloading kepub, try downloading ePub and see if that works.

davidfor · 07-02-2017, 11:24 PM

Quote:

Originally Posted by JSWolf

If this is an ePub from Kobo and you are downloading kepub, try downloading ePub and see if that works.

You might want to read the thread. That is stated in the first post.

moorekom · 07-03-2017, 05:52 PM

Ok. I factory reset the device again and the kepub issue is gone for those two books. Some of the kepubs still hang when I open them but after the device restarts, I am able to open them without any issues. But, the battery drain issue is back. At this point, I can only guess that this is because of the firmware. I don't think there is any other viable explanation for it. I have changed the setting for the device to power off after 10 mins to circumvent the battery issue for now. I'm hoping Kobo releases the update to fix this as the email from their rep stated. Thanks to everyone who took time to help me with this. Especially @davidfor. Thanks man.

I'll check with Kobo regarding the battery issue and try to update here if I hear anything.

Alanon · 09-15-2017, 05:01 AM

Has anyone been able to reach a definitive conclusion or potential fix regarding this issue? I've been experimenting for a while now, ever since I received my Aura One, and I've been unable to ascertain any rule. It's not just technical files, but plain old books with nothing special about them at all.

I've tried them with many ToC entries, high-res covers, large files, small files. At first, I thought that Calibre conversion was to blame, but this morning I downloaded a preview of the Delphi Classics Dickens from the Kobo store, and it restarted immediately, just like my converted epub did.

At this point, everything would indicate that there's something wrong with the firmware, since almost all of the books I've tried seem to work every time - right after that restart. Did anyone try to revert the firmware by any chance, and see if there is a difference?

davidfor · 09-15-2017, 07:20 AM

As far as I can work out, it is a size issue. The number of ToC entries and the amount of text in each chapter. It is probably also affected by the code complexity in the book. How many books you have on the device might affect it as well.

What happens when you open a kepub is that the device calculates the word count for all the ToC entries in the book. This is stored in the database and used for the chapter graph in the in book stats. What seems to be happening is that when the word counting takes to long, sickel (the process watcher) thinks it has detected a hung process and restart the device. When you open the book after the restart, it works. This is probably because the word counts for some ToC entries were stored, and only a few need to be calculated.

If this theory is right, then anything that affects the time taken to calculate the word count could affect this. Book size, chapter size, number of ToC entries, complicated code in the book, larger database, other thing running. Even opening the book immediately after a restart might be enough as nothing extra is running and the memory is probably cleaner.

It is an annoying problem to reproduce as it doesn't always happen. I have put a book on the device and had it restart. Then deleted the book and put it back on, and it was OK. And it is inconsistent across my devices. And that makes me think my theory above is good.

One thing I am surprised at is that a preview triggered this. Can you post the link so I can try it?

Alanon · 09-15-2017, 01:57 PM

@davidfor: Here's the link. To be fair, it's a large file and even the preview is 15MB in size and full of ToC entries, though I have examples of (sideloaded and converted) kepubs that are under 2MBs which error out completely, and for which even a restart doesn't fix the problem. While I believe that your assessment is actually correct, what struck me initially is that the preview experience was not different from the one I had when converting that same Delphi epub file to kepub.

I've seen (physically) much larger kepubs be able to open instantly, while others, notably smaller, I simply couldn't get to work. While I'm aware that epubs and the code aspect of the problem is an often incomprehensible maze, and that it's impossible for any solution to be perfect, the fact that Kobo itself has that kind of file made me feel a bit more optimistic that it is, in fact, a bug, and not some natural and expectable consequence of potential conversion pitfalls.

Currently, I only convert footnote-laden and highlight-worthy files and push through the reboots because of the vastly superior experience on the kepubs. I wouldn't even be insisting on this issue so much, were it not for a gnawing sense that so many errors and restarting are ultimately bad for the device.

compurandom · 09-19-2017, 06:38 AM

I've found that some books that I've built and cause this problem cause less problems if I strip out javascript and other unnecessary stuff -- which contributes to the code complexity and size theory I think. Books (i.e., downloaded web pages) with lots of javascript cause more problems even if they are small.

If it is stuffing info in the database, is there any chance the calibre kobo driver could precalculate this stuff and put it in the database instead? Maybe on a single shot basis when a book is causing issues...

davidfor · 09-19-2017, 07:37 AM

Quote:

Originally Posted by compurandom

I've found that some books that I've built and cause this problem cause less problems if I strip out javascript and other unnecessary stuff -- which contributes to the code complexity and size theory I think. Books (i.e., downloaded web pages) with lots of javascript cause more problems even if they are small.

Yes, any extraneous code would increase the chance of this happening.

Quote:

If it is stuffing info in the database, is there any chance the calibre kobo driver could precalculate this stuff and put it in the database instead? Maybe on a single shot basis when a book is causing issues...

I have considered that. I don't want to populate most of the database entries as I really don't know how. But, fixing this sort of thing should be pretty safe. Of course, to do that, I would have to be able to test the change. And at the moment, I can't reproduce it with the firmware I am using. Which is probably a good thing

compurandom · 09-25-2017, 07:37 AM

Quote:

Originally Posted by davidfor

Of course, to do that, I would have to be able to test the change. And at the moment, I can't reproduce it with the firmware I am using. Which is probably a good thing

Next time I build a book that causes issues, I'll try to remember to post it here.

I seem to recall having problems with a couple of gutenberg books too, but that may have been the large toc issue or something.

I think a lot of them work ok after hanging once and rebooting once, which is also irritating.

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06-28-2017, 08:43 PM	#16
PeterT Grand Sorcerer Posts: 12,162 Karma: 73448616 Join Date: Nov 2007 Location: Toronto Device: Nexus 7, Clara, Touch, Tolino EPOS	If the issue is related to the TOC then the only thing that would help is simplifying it! Sent from my Nexus 7 using Tapatalk

07-02-2017, 10:24 PM	#17
JSWolf Resident Curmudgeon Posts: 73,940 Karma: 128903250 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	If this is an ePub from Kobo and you are downloading kepub, try downloading ePub and see if that works.

07-03-2017, 05:52 PM	#19
moorekom Connoisseur Posts: 53 Karma: 2898874 Join Date: Nov 2016 Device: Kindle Scribe, Oasis 3, Kobo Aura One, Kobo Forma, Onyx Note pro.	Ok. I factory reset the device again and the kepub issue is gone for those two books. Some of the kepubs still hang when I open them but after the device restarts, I am able to open them without any issues. But, the battery drain issue is back. At this point, I can only guess that this is because of the firmware. I don't think there is any other viable explanation for it. I have changed the setting for the device to power off after 10 mins to circumvent the battery issue for now. I'm hoping Kobo releases the update to fix this as the email from their rep stated. Thanks to everyone who took time to help me with this. Especially @davidfor. Thanks man. I'll check with Kobo regarding the battery issue and try to update here if I hear anything.

09-15-2017, 05:01 AM	#20
Alanon Connoisseur Posts: 76 Karma: 10742 Join Date: Jul 2017 Location: Serbia Device: Kobo Aura One	Has anyone been able to reach a definitive conclusion or potential fix regarding this issue? I've been experimenting for a while now, ever since I received my Aura One, and I've been unable to ascertain any rule. It's not just technical files, but plain old books with nothing special about them at all. I've tried them with many ToC entries, high-res covers, large files, small files. At first, I thought that Calibre conversion was to blame, but this morning I downloaded a preview of the Delphi Classics Dickens from the Kobo store, and it restarted immediately, just like my converted epub did. At this point, everything would indicate that there's something wrong with the firmware, since almost all of the books I've tried seem to work every time - right after that restart. Did anyone try to revert the firmware by any chance, and see if there is a difference?

09-15-2017, 07:20 AM	#21
davidfor Grand Sorcerer Posts: 24,907 Karma: 47303748 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	As far as I can work out, it is a size issue. The number of ToC entries and the amount of text in each chapter. It is probably also affected by the code complexity in the book. How many books you have on the device might affect it as well. What happens when you open a kepub is that the device calculates the word count for all the ToC entries in the book. This is stored in the database and used for the chapter graph in the in book stats. What seems to be happening is that when the word counting takes to long, sickel (the process watcher) thinks it has detected a hung process and restart the device. When you open the book after the restart, it works. This is probably because the word counts for some ToC entries were stored, and only a few need to be calculated. If this theory is right, then anything that affects the time taken to calculate the word count could affect this. Book size, chapter size, number of ToC entries, complicated code in the book, larger database, other thing running. Even opening the book immediately after a restart might be enough as nothing extra is running and the memory is probably cleaner. It is an annoying problem to reproduce as it doesn't always happen. I have put a book on the device and had it restart. Then deleted the book and put it back on, and it was OK. And it is inconsistent across my devices. And that makes me think my theory above is good. One thing I am surprised at is that a preview triggered this. Can you post the link so I can try it?

09-15-2017, 01:57 PM	#22
Alanon Connoisseur Posts: 76 Karma: 10742 Join Date: Jul 2017 Location: Serbia Device: Kobo Aura One	@davidfor: Here's the link. To be fair, it's a large file and even the preview is 15MB in size and full of ToC entries, though I have examples of (sideloaded and converted) kepubs that are under 2MBs which error out completely, and for which even a restart doesn't fix the problem. While I believe that your assessment is actually correct, what struck me initially is that the preview experience was not different from the one I had when converting that same Delphi epub file to kepub. I've seen (physically) much larger kepubs be able to open instantly, while others, notably smaller, I simply couldn't get to work. While I'm aware that epubs and the code aspect of the problem is an often incomprehensible maze, and that it's impossible for any solution to be perfect, the fact that Kobo itself has that kind of file made me feel a bit more optimistic that it is, in fact, a bug, and not some natural and expectable consequence of potential conversion pitfalls. Currently, I only convert footnote-laden and highlight-worthy files and push through the reboots because of the vastly superior experience on the kepubs. I wouldn't even be insisting on this issue so much, were it not for a gnawing sense that so many errors and restarting are ultimately bad for the device.

09-19-2017, 06:38 AM	#23
compurandom Guru Posts: 919 Karma: 417282 Join Date: Jun 2015 Device: kobo aura h2o, kobo forma	I've found that some books that I've built and cause this problem cause less problems if I strip out javascript and other unnecessary stuff -- which contributes to the code complexity and size theory I think. Books (i.e., downloaded web pages) with lots of javascript cause more problems even if they are small. If it is stuffing info in the database, is there any chance the calibre kobo driver could precalculate this stuff and put it in the database instead? Maybe on a single shot basis when a book is causing issues...

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