EPUB to EPUB conversion

roger64 · 05-17-2014, 06:14 AM

Hi

I had a curious experience. One of my EPUB did validate fully with the Calibre editor. However, it did not display with iBooks which only gave some terse and unhelpful explanations like:
- "le chargement a échoué car la ressource requise est manquante." One resource is missing (which one, God knows it).
- "Impossible d'ouvrir. il est formaté incorrectement ou n'est pas à un format qu'ibooks peut ouvrir". Bad formatting, or wrong format.

The surprise is that a plain conversion from EPUB to EPUB using Calibre solved the problem, so I hasted to compare the differences between the two books. It would be too long to quote them here. Many made perfect sense (reducing the size of some images, inserting a calibre class everywhere, ... so I will not comment them here.

Some others looked more puzzling to me:

1. - toc.html
I had originally inserted a toc.html made with Calibre. I had moved it at the end of the book but Calibre did not agree and put it back at the front...

2. - meta http-equiv?
- this sentence was systematically inserted under the <head> of every file, under the title tag:
<meta hhtp-equiv="Content-Type" content="text/html; charset=utf-8"/>
Is this a way to "compensate" from the absence of a DOCTYPE?
- also the xml declaration was made slightly longer. lang="fr" became xml:lang="fr"

3. - splitting files instead of manual pagebreaks
Manual pagebreaks (<p class="break"> </p>) were systematically replaced by a split file (even if this was for a small paragraph)

4. - Embedded font file suppressed
The com.apple.ibooks.display-options.xml file was suppressed though I had embedded fonts. The fonts were correctly displayed. Is this file useless?

kovidgoyal · 05-17-2014, 09:30 AM

Conversion does many, many things to make sure its output works across all devices.

1. I'd guess this is because of a non-linear spine item

2. That's an ecoding declaration, it's there for redundancy.

3. Splittling files at page breaks is a good tyhing, makes your epub work faster on limited devices. There is a conversion option to turn it off.

4. IIRC that file is obsolete with newer versions of ibooks, though since I never touch ibooks with a 10 foot barge pole, I cant be sure.

roger64 · 05-17-2014, 11:07 AM

Thanks for your reply and your informations.

I will have a look at the conversion options.

05-17-2014, 06:14 AM	#1
roger64 Wizard Posts: 2,623 Karma: 3000161 Join Date: Jan 2009 Device: Kindle PW3 (wifi)	EPUB to EPUB conversion Hi I had a curious experience. One of my EPUB did validate fully with the Calibre editor. However, it did not display with iBooks which only gave some terse and unhelpful explanations like: - "le chargement a échoué car la ressource requise est manquante." One resource is missing (which one, God knows it). - "Impossible d'ouvrir. il est formaté incorrectement ou n'est pas à un format qu'ibooks peut ouvrir". Bad formatting, or wrong format. The surprise is that a plain conversion from EPUB to EPUB using Calibre solved the problem, so I hasted to compare the differences between the two books. It would be too long to quote them here. Many made perfect sense (reducing the size of some images, inserting a calibre class everywhere, ... so I will not comment them here. Some others looked more puzzling to me: 1. - toc.html I had originally inserted a toc.html made with Calibre. I had moved it at the end of the book but Calibre did not agree and put it back at the front... 2. - meta http-equiv? - this sentence was systematically inserted under the <head> of every file, under the title tag: <meta hhtp-equiv="Content-Type" content="text/html; charset=utf-8"/> Is this a way to "compensate" from the absence of a DOCTYPE? - also the xml declaration was made slightly longer. lang="fr" became xml:lang="fr" 3. - splitting files instead of manual pagebreaks Manual pagebreaks (<p class="break"> </p>) were systematically replaced by a split file (even if this was for a small paragraph) 4. - Embedded font file suppressed The com.apple.ibooks.display-options.xml file was suppressed though I had embedded fonts. The fonts were correctly displayed. Is this file useless? Last edited by roger64; 05-17-2014 at 06:17 AM.

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05-17-2014, 09:30 AM	#2
kovidgoyal creator of calibre Posts: 45,198 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Conversion does many, many things to make sure its output works across all devices. 1. I'd guess this is because of a non-linear spine item 2. That's an ecoding declaration, it's there for redundancy. 3. Splittling files at page breaks is a good tyhing, makes your epub work faster on limited devices. There is a conversion option to turn it off. 4. IIRC that file is obsolete with newer versions of ibooks, though since I never touch ibooks with a 10 foot barge pole, I cant be sure.

05-17-2014, 11:07 AM	#3
roger64 Wizard Posts: 2,623 Karma: 3000161 Join Date: Jan 2009 Device: Kindle PW3 (wifi)	Thanks for your reply and your informations. I will have a look at the conversion options.

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