Convert from epub3 to epub2 (yes, backwards)

[BKh]

Originally Posted by Hitch

you seem to have deleted the toc.html, is that right? You're aware that you'll need that at the KDP? The HTML TOC is pretty much required at Amazon now. The NCX will not suffice, as not all of the devices can use that for display purposes to the human reader. If you are not yet done, you may wish to reproduce an HTML TOC to use when you load the ePUB at the KDP or whatever process you determine to use.

Hitch

Yes, It really is confusing. I did create one. Thanks for the reminder.

[Hitch]

Originally Posted by BKh

Yes, It really is confusing. I did create one. Thanks for the reminder.

You bet. Glad to be of service.

Hitch

[BKh]

So, I changed back to 2.0 by the method I proposed. These are the errors I received and how I solved them. If anyone could give an opinion on how ill advised my solutions are, that would be much appreciated. After I made these changes there were no errors detected.

All of the errors were in OEBPS/content.opf

ERROR: The "prefix" attribute is not an allowed attribute of the <package> element.
LINE: <package xmlns="http://www.idpf.org/2007/opf" prefix="ibooks: http://vocabulary.itunes.apple.com/rdf/ibooks/vocabulary-extensions-1.0/" unique-identifier="bookid" version="2.0">
sOLUTION: DELETED prefix="ibooks: http://vocabulary.itunes.apple.com/rdf/ibooks/vocabulary-extensions-1.0/"

ERROR:  The "property" attribute is not an allowed attribute of the <meta> element.
ERROR:The required attribute "content" is missing from the <meta> element.
ERROR: The required attribute "name" is missing from the <meta> element.
LINE:     <meta property="ibooks:specified-fonts">true</meta>
sOLUTION: DELETED WHOLE LINE <meta property="ibooks:specified-fonts">true</meta>

ERROR: The "property" attribute is not an allowed attribute of the <meta> element.
ERROR: The required attribute "content" is missing from the <meta> element.
ERROR: The required attribute "name" is missing from the <meta> element.
LINE:     <meta property="dcterms:modified">2016-05-14T18:21:09Z</meta>
sOLUTION: DELETED WHOLE LINE     <meta property="dcterms:modified">2016-05-14T18:21:09Z</meta>

I also uploaded it to KDP and it was accepted.

[DiapDealer]

There are some differences between EPUB2/3 metadata. I think a better solution would have been to look at similar metadata entries for EPUB2 and to modify yours to match. But as long as none of the entries are required, I suppose deleting them can work, too.

Does InDesign really add all of that proprietary iBooks meta stuff by default?

[BKh]

Originally Posted by DiapDealer

There are some differences between EPUB2/3 metadata. I think a better solution would have been to look at similar metadata entries for EPUB2 and to modify yours to match. But as long as none of the entries are required, I suppose deleting them can work, too.

I am so familiar with metadata coding that I was afraid to tinker too much. I was banking on the fact that if something was missing, the checker would tell me.

Does InDesign really add all of that proprietary iBooks meta stuff by default?

I'm not sure how that got in there. I checked a book I created exporting as epub2 from indesign and those tags are there as well. So That is probably how they got there.

Thanks!

[Moonraker]

I had a great deal of trouble converting epub3 back to epub2. Following previous instructions on this forum I converted the epub to .zip and then edited the .opf file to change the package back to version 2.

But then I couldn't work out how to get my new .opf file back into the zip file so I could then change the extension back to .epub.

I finally succeeded without doing any zipping and editing by converting the epub3 to .azw in Calibre. Then using Calibre again I converted it to epub and low and behold discovered it was now epub2

[DiapDealer]

Originally Posted by Moonraker

But then I couldn't work out how to get my new .opf file back into the zip file so I could then change the extension back to .epub.

You unzip, edit the opf, and then rezip everything (new opf included) into a new archive.

Or you use an archiving utility that allows you to edit files without unzipping them first (actually many just unzip stuff to a temp location and rezip things behind the scenes when you're done editing them, but the effect is the same--except the mimetype file will be compressed and possibly out of order, but Sigil will fix that when opening/saving).

A calibre conversion is another option for sure. But many want to keep the original code as unaltered as possible when downgrading from 3 to 2.

I myself, don't bother downgrading. I've yet to run into a commercially sold epub3 that didn't render acceptably in most popular epub2 reading systems. And if it's a "feature-rich" epub3, downgrading it will break its functionality anyway.

[BKh]

Originally Posted by DiapDealer

I myself, don't bother downgrading. I've yet to run into a commercially sold epub3 that didn't render acceptably in most popular epub2 reading systems. And if it's a "feature-rich" epub3, downgrading it will break its functionality anyway.

I believe that Amazon will not accept an epub3 format file. But that could have changed.

[Doitsu]

Originally Posted by BKh

I believe that Amazon will not accept an epub3 format file. But that could have changed.

KindleGen has partial epub3 support and the Amazon Kindle Publishing Guidelines specifically mention that epub3 files are supported.

To create Kindle files using KindleGen, you need:

• A single HTML file that represents the entire book; or
• EPUB-compliant files. (IDPF’s EPUB spec is available at http://www.idpf.org/epub/30/spec/epub30-overview.html)

I.e., unless you use scripting or advanced epub3 features, you shouldn't have any problems with AMAZON KDP.