Built-in viewer displaying mobi files oddly

KindaFarty · 05-11-2011, 12:55 AM

Hello!

I use calibre extensively to manage my ebook library. I store all books in both epub & mobi format, as I use both a Kindle & Nook.

All my books start as epubs, then I convert to mobi using calibre. Usually with default conversion settings, as I get the epubs how I want them before I convert (with Sigil).

The built-in calibre reader displays the epubs perfectly. However, when I use calibre's built-in reader to read a mobi, the book appears to have lost it's formatting somehow. Pages are all blended together, there is no separation between the table of contents and the beginning of the story, text has been resized in certain areas, etc... just all kinds of problems.

Now, when I view that same book on the Kindle device, it displays just fine. No errors. Same when I view it on the Kindle for pc app.

So, I guess I'm asking if there's any known reason for calibre's reader to display the mobis in such a way when they appear differently in the Kindle reader.

Below, the image on the left is the (correctly displayed) epub; the image on the right is the mobi.

Thanks in advance.

cybmole · 05-11-2011, 01:14 AM

try resetting all calibre convert preferences back to default for that book., then reconvert it. you may have left something in find & replace. ( leaving just one blank space in there can be disastrous)
you can post short extracts of text to show the problem if it persists.

+ check your workflow - i.e. that the book that looks fine on Kindle is the exact same file that looks wrong in calibre viewer , not a newer or older version?

+ confirm for us that you have latest version of calibre - I believe there was a temporary glitch to do with mobi font sizing in one recent version that was quickly fixed

Manichean · 05-11-2011, 03:15 AM

Quote:

Originally Posted by KindaFarty

So, I guess I'm asking if there's any known reason for calibre's reader to display the mobis in such a way when they appear differently in the Kindle reader.

This is probably because the Calibre ebook viewer doesn't display MOBI. Internally, it converts non-ePub files to ePub before displaying them.

cybmole · 05-11-2011, 03:28 AM

true, but an epub source which calibre has converted to Mobi should appear just like the source, in calibre viewer unless there is strange CSS code in that book which does not convert/reconvert correctly.

I have converted lots of epub to mobi with calibre & have viewed the "mobi" with calibre viewer Ok - [even though I'm not really viewing "mobi" when I do that, as you have already explained. ] In fact, a while back we got into tweaking backgound colours n stuff for calibre viewer to match Kindle for PC

I then got very similar viewing experience with K for PC & the C viewer side by side on screen.

I think we need to know if ithis "bug" happens for more than 1 book & we need to see some sample of html & CSS for a page that is getting mangled.

Manichean · 05-11-2011, 04:47 AM

Quote:

Originally Posted by cybmole

true, but an epub source which calibre has converted to Mobi should appear just like the source, in calibre viewer unless there is strange CSS code in that book which does not convert/reconvert correctly.

No, and it's rather easy to see why that's not the case: Look at the specifications of ePub and MOBI. MOBI is a rather restricted format, so conversion should be considered lossy (as far as formatting goes, information is, of course, preserved). Reconverting from a previously lossy converted source doesn't give you the original data.

cybmole · 05-11-2011, 04:58 AM

you are. of course, technically correct, but empirically I never saw any differences when repeatedly flipping formats, except for drop caps ( not mobi supported) background shading ( ditto), and fractional indents like 1.5 em - Kindle rounds up to 2.0.

nothing like the OP's thumbnail image. where some page-break-before or page-break-after code seems to have gone walkabout.

could be that he needs to also do an epub to epub step in calibre to force generate one html file per chapter, as the viewer will then page break on each new file. but has he seems to have dropped out of the conversation we'll maybe never know.

I'm kinda hoping that amazon will have to add epub support eventually, maybe in Kindle 4, & mobi can then just fade away, like LIT.doesn't make great business sense for Amazon though, so my K3 is not up for sale on ebay yet!

Manichean · 05-11-2011, 05:36 AM

Quote:

Originally Posted by cybmole

you are. of course, technically correct, but empirically I never saw any differences when repeatedly flipping formats, except for drop caps ( not mobi supported) background shading ( ditto), and fractional indents like 1.5 em - Kindle rounds up to 2.0.

nothing like the OP's thumbnail image. where some page-break-before or page-break-after code seems to have gone walkabout.

It would depend, I believe, on the markup used for those paragraphs. I still say that this is a consequence of the viewer converting internally. If the formatting errors were present in dedicated MOBI viewers and/or devices, I'd be less sure, but this looks like a done deal.

Quote:

I'm kinda hoping that amazon will have to add epub support eventually, maybe in Kindle 4, & mobi can then just fade away, like LIT.doesn't make great business sense for Amazon though, so my K3 is not up for sale on ebay yet!

Won't happen, I think. The reasons are that a) Amazon controls MOBI (they bought Mobipocket) and b) this, effectively, locks (many/most) Kindle customers to Amazon as their sole ebook vendor.
On that topic, I seem to remember there being some unofficial firmware available for some Kindle models that adds ePub support, but I don't remember in which thread I saw it and what it was called.

ldolse · 05-11-2011, 06:35 AM

There are several cases where formatting data can get lost during conversion and there is nothing that can be done about it with the conversion engine that wouldn't require a monumental effort. That's because mobi can break all sorts of modern html rules, and in order to get to epub it's got to be converted to valid xhtml. The mobi markup is massaged before converting to xhtml to prioritize what will be kept vs. lost, but in some mobi files the rules get broken so badly something will get dropped (formatting, not textual data).

Regarding the OP's complaint though, this is just a Calibre viewer issue - it doesn't display/create page breaks from mobi files during it's conversion to OEB for the viewer - I don't believe Kovid has any plans to address this, but fully converting to epub and viewing that will fix this problem.

kovidgoyal · 05-11-2011, 12:26 PM

calibre's viewer does not support the page-break-before/after CSS styles. Not surprising since it is not a page based viewer. MOBI (or atleast the upshifted version of MOBI used internally) uses that, which is why you will not see page breaks in the MOBI.

KindaFarty · 05-13-2011, 06:48 PM

Thanks you guys, for all the comments here. I found your your responses to be more than helpful. The mobi files seem to be converting just fine; I was simply concerned that I couldn't get them to display properly in the calibre reader. As long as they display properly on the Kindle itself, no worries.

05-11-2011, 12:55 AM	#1
KindaFarty Junior Member Posts: 5 Karma: 10 Join Date: May 2011 Device: Nook	Built-in viewer displaying mobi files oddly Hello! I use calibre extensively to manage my ebook library. I store all books in both epub & mobi format, as I use both a Kindle & Nook. All my books start as epubs, then I convert to mobi using calibre. Usually with default conversion settings, as I get the epubs how I want them before I convert (with Sigil). The built-in calibre reader displays the epubs perfectly. However, when I use calibre's built-in reader to read a mobi, the book appears to have lost it's formatting somehow. Pages are all blended together, there is no separation between the table of contents and the beginning of the story, text has been resized in certain areas, etc... just all kinds of problems. Now, when I view that same book on the Kindle device, it displays just fine. No errors. Same when I view it on the Kindle for pc app. So, I guess I'm asking if there's any known reason for calibre's reader to display the mobis in such a way when they appear differently in the Kindle reader. Below, the image on the left is the (correctly displayed) epub; the image on the right is the mobi. Thanks in advance.

05-11-2011, 03:28 AM	#4
cybmole Wizard Posts: 3,720 Karma: 1759970 Join Date: Sep 2010 Device: none	true, but an epub source which calibre has converted to Mobi should appear just like the source, in calibre viewer unless there is strange CSS code in that book which does not convert/reconvert correctly. I have converted lots of epub to mobi with calibre & have viewed the "mobi" with calibre viewer Ok - [even though I'm not really viewing "mobi" when I do that, as you have already explained. ] In fact, a while back we got into tweaking backgound colours n stuff for calibre viewer to match Kindle for PC I then got very similar viewing experience with K for PC & the C viewer side by side on screen. I think we need to know if ithis "bug" happens for more than 1 book & we need to see some sample of html & CSS for a page that is getting mangled. Last edited by cybmole; 05-11-2011 at 03:30 AM.

05-11-2011, 06:35 AM	#8
ldolse Wizard Posts: 1,337 Karma: 123455 Join Date: Apr 2009 Location: Malaysia Device: PRS-650, iPhone	There are several cases where formatting data can get lost during conversion and there is nothing that can be done about it with the conversion engine that wouldn't require a monumental effort. That's because mobi can break all sorts of modern html rules, and in order to get to epub it's got to be converted to valid xhtml. The mobi markup is massaged before converting to xhtml to prioritize what will be kept vs. lost, but in some mobi files the rules get broken so badly something will get dropped (formatting, not textual data). Regarding the OP's complaint though, this is just a Calibre viewer issue - it doesn't display/create page breaks from mobi files during it's conversion to OEB for the viewer - I don't believe Kovid has any plans to address this, but fully converting to epub and viewing that will fix this problem. Last edited by ldolse; 05-11-2011 at 06:40 AM.

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05-11-2011, 01:14 AM	#2
cybmole Wizard Posts: 3,720 Karma: 1759970 Join Date: Sep 2010 Device: none	try resetting all calibre convert preferences back to default for that book., then reconvert it. you may have left something in find & replace. ( leaving just one blank space in there can be disastrous) you can post short extracts of text to show the problem if it persists. + check your workflow - i.e. that the book that looks fine on Kindle is the exact same file that looks wrong in calibre viewer , not a newer or older version? + confirm for us that you have latest version of calibre - I believe there was a temporary glitch to do with mobi font sizing in one recent version that was quickly fixed

05-11-2011, 04:58 AM	#6
cybmole Wizard Posts: 3,720 Karma: 1759970 Join Date: Sep 2010 Device: none	you are. of course, technically correct, but empirically I never saw any differences when repeatedly flipping formats, except for drop caps ( not mobi supported) background shading ( ditto), and fractional indents like 1.5 em - Kindle rounds up to 2.0. nothing like the OP's thumbnail image. where some page-break-before or page-break-after code seems to have gone walkabout. could be that he needs to also do an epub to epub step in calibre to force generate one html file per chapter, as the viewer will then page break on each new file. but has he seems to have dropped out of the conversation we'll maybe never know. I'm kinda hoping that amazon will have to add epub support eventually, maybe in Kindle 4, & mobi can then just fade away, like LIT.doesn't make great business sense for Amazon though, so my K3 is not up for sale on ebay yet!

05-11-2011, 12:26 PM	#9
kovidgoyal creator of calibre Posts: 45,295 Karma: 27111240 Join Date: Oct 2006 Location: Mumbai, India Device: Various	calibre's viewer does not support the page-break-before/after CSS styles. Not surprising since it is not a page based viewer. MOBI (or atleast the upshifted version of MOBI used internally) uses that, which is why you will not see page breaks in the MOBI.

05-13-2011, 06:48 PM	#10
KindaFarty Junior Member Posts: 5 Karma: 10 Join Date: May 2011 Device: Nook	Thanks you guys, for all the comments here. I found your your responses to be more than helpful. The mobi files seem to be converting just fine; I was simply concerned that I couldn't get them to display properly in the calibre reader. As long as they display properly on the Kindle itself, no worries.

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