Page numbers wrong on Kobo!!

[cabal2000]

Hi guys I am very new to Calibre. I uploaded a ePub to my Kobo Glo (latest firmware) that has 1179 pages but on the Kobo it only shows 535!! Is there a way to fix this?

[davidfor]

Firstly, which is wrong and needs to be fixed?

The reason for question is that page counts is something that has been endlessly discussed across this forum with religious fervour.

There are lots of ways to calculate the page count. I can think of ways that this is done in calibre. So, it does depend on what you are looking at there. If you are using the Count Pages plugin and have the ADE algorithm it should be roughly the same. If you are using a different algorithm, or the calibre viewer page count, then it won't match.

And Kobo uses different algorithms for epubs and kepubs. And Kindles do it another way.

[cabal2000]

Thanks. It is with the KOBO for sure. How do I fix it in Calibre?

[DNSB]

Originally Posted by cabal2000

Thanks. It is with the KOBO for sure. How do I fix it in Calibre?

Basically, for epubs you would need to generate Adobe's non-standard and poorly supported page-map or the standard and poorly supported pagelist.

<pulling out soapbox>
However worrying about page numbers in a reflowable format where the amount of data on the screen can and does vary widely with font size, line and paragraph spacing, margins, etc. is, at best, an exercise in futility. The Adobe synthetic page algorithm has at least the virtue of being consistent across devices.

If you are worrying about matching page numbers to a print edition, we'd have to ask which print edition as the page numbering will vary from hardcover to trade paperback to paperback. Even if you stick to hardcover only, the page numbers are not necessarily consistent. I noted this in one textbook where the 7th reprint was re-typeset, the illustrations were redone and various errata corrected resulting in a book with 11 fewer pages.
<putting soapbox away till next time>

[ZodWallop]

Originally Posted by cabal2000

Hi guys I am very new to Calibre. I uploaded a ePub to my Kobo Glo (latest firmware) that has 1179 pages but on the Kobo it only shows 535!! Is there a way to fix this?

You might try converting your ePubs to kepubs.

You'll likely never get the same page count on different devices as everyone has told you. But if you have Calibre convert from ePub to kepub when sending books to the Kobo, the page count will at least more accurately reflect the number of 'screen pages' in the book.

On my Nook, if a chapter is shown as 10 pages, I know it more likely is 13-15 page turns to finish it. On my Kobo if it says a chapter is 10 pages, turning the page 10 times will reach the end.

[davidfor]

Originally Posted by cabal2000

Thanks. It is with the KOBO for sure. How do I fix it in Calibre?

How do you know that?

Here is the problem. I know how the page numbers are calculated. I know what algorithm is used for epubs on the Kobo devices. I know how calibre viewer calculates the page count. I know all the ways that the Count Pages plugin calculates the page counts.

It is possible the Kobo page count is wrong. But, without some details, we can't be sure. And can't tell you how to fix it. Without knowing what count you are comparing it to, or what format you are using on the device, we can't tell you how to fix it. Or if there is something that can be fixed.

But, overall, I'm with DNSB on this. The only page count that is close to comparable across multiple devices/apps is the Adobe page count. Which Kobo use for epubs. All the others are dependent on other things: screen/page size, font chosen and size, lines spacing and probably other things I can't think of now.

[jackie_w]

Originally Posted by davidfor

But, overall, I'm with DNSB on this. The only page count that is close to comparable across multiple devices/apps is the Adobe page count. Which Kobo use for epubs. All the others are dependent on other things: screen/page size, font chosen and size, lines spacing and probably other things I can't think of now.

The kepub page count is not too bad as long as you set 'Display progress for: Entire book'. It seems to be consistent cross other Kobo eink devices, regardless of screen-size, font, line-spacing etc. Not consistent with other eink brands or 3rd-party Android reading apps, though, where the Adobe page count is the only real contender for epubs.

I'd really like to know what algorithm Kobo use. Have you ever been able to delve deep enough into the firmware to find out more?

[davidfor]

Originally Posted by jackie_w

The kepub page count is not too bad as long as you set 'Display progress for: Entire book'. It seems to be consistent cross other Kobo eink devices, regardless of screen-size, font, line-spacing etc.

Between the Kobo ereaders it works well.

Not consistent with other eink brands or 3rd-party Android reading apps, though, where the Adobe page count is the only real contender for epubs.

I'd really like to know what algorithm Kobo use. Have you ever been able to delve deep enough into the firmware to find out more?

I've never looked. I originally assumed it was similar to the Adobe algorithm. It could be exactly that as, from memory, it produces higher numbers than for the equivalent epub. All the extra spans should mean page count using that. But, after a quick experiment, it appears to be based on the word count.

What I did was to put two copies of an epub on my Glo. One I named with the extension .kepub.epub so that it would be opened with the kepub render but not have the no spans. So, both copies were identical. When I opened them, the epub version showed 230 pages and the kepub viewer showed 256.

Because I know the kepub viewer calculates word counts for each chapter to use for the chapter graph, I have wondered if the word count was used for the full book page count. So, I went into the database and for the pseudo-kepub version, changed all the word counts to 10. When I opened the book, it had 40 pages. And the bars in the graph were all the same size.

That tells me the kepub full-book page count is from the word count. But, I don't know what the calculation is. After my fiddling, the total word count is 390. 390/40 means 9 words per page. Far to small. But there are 40 records for the book with zero (the title page) or more words. That I think explains the page count.

The unadulterated version has 79184 words (77242 words according to the Count Pages plugin). That would be 309 words per page. A quick search on the web suggests between 250 and 300 words per page for a paperback. And as they probably calculating pages per chapter and adding them up, 300 sounds a likely number. And setting the word counts to 300, I still have 40 pages. But, I set one copy to 301 words, and another to 600. And I had 40 and 79 pages. A bit more experimentation, and it looks like the change is between 475 and 500 words per chapter to go from 40 to 79 pages. But, 750 is still 79 pages, and 800 words per chapter gives 118 pages (cover plus three pages per chapter). There is an inconsistency there, so either it is not a straight number of words per page (possible), or I made a mistake in my testing (probably).

In any case, the full-book page count for kepubs is looks to be based on the word count. Somehow.

For completeness, the page count for the same book in other ways:
- calibre viewer: 447
- Count Pages - ADE algorithm: 230
- Count Pages - Paragraphs (APNX Accurate) : 265
- Kobo store - 280
- The kepub from the store - 256 (same as the epub when treated as a kepub!)
- Goodreads - 240 (Paperback and Kindle. Other editions don't have a page count)

@cabal2000: The above was done because of @jackie_w question and my curiosity (I suspect someone knew exactly what would happen). But, it demonstrates why I am asking how you know what is wrong. And without that, we can't say how to fix it.

Now, I might go and read. And try not to count the words on the screen.

[jackie_w]

Originally Posted by davidfor

In any case, the full-book page count for kepubs is looks to be based on the word count. Somehow.

Thanks for doing all that I remember reaching a similar conclusion when I did some experiments a couple of years ago, but I didn't get any further than "something to do with word count".

Originally Posted by davidfor

The above was done because of @jackie_w question and my curiosity (I suspect someone knew exactly what would happen).

Originally Posted by davidfor

Now, I might go and read. And try not to count the words on the screen.

How does Kobo determine wordcount, anyway? (only joking)

Small aside ... when I was creating my text-to-speech plugin I included wordcount per chapter info (as calculated by calibre). Just for interest I selected one epub and compared these chapter wordcounts with those in my Kobo database for the same book. For most chapters they didn't compare at all well. For chapters such as "Part One", with only 2 words, they matched, but for anything with a few paragraphs they didn't. At the time, I didn't have it in me to investigate further ... maybe one day ... or, like you, I could just go and read a book. I'm told these eink gadgets can be used for reading as well as messing about