I know there are two nice kepub converters in Calibre,
Kobo Touch Extended Driver and
KePub Outtput Plugin.
They work perfect to me. But I often convert files manually because I don't use Calibre for manage epub files often. I used to change only extention from epub to kepub.epub. I have not much trouble with it but I lost cover images on my kobo. Therefore I add a step for cover image.
How to indicate cover images in content.opt file.
1)epub (epub2)
epub use metadata to identify cover image. It requires two steps, examples are as follows.
Code:
#metadata
<meta name="cover" content="cover-id" />
#manifest
<item id="cover-id" href="cover.jpeg" media-type="image/jpeg" />
2)kepub.epub (epub3)
kepub doesn't use metadata any more. It only uses
properties="cover-image". Example is shown below.
Code:
#manifest
<item properties="cover-image" id="ci" href="cover.jpg" media-type="image/jpeg" />
I convert epub files to kepub.epub by three steps as follows.
1) Open epub file by winzip, 7-Zip or Sigil. And open the content.opt file.
2) Identify the cover image item in manifest. Add
properties="cover-image" in it as shown above.
3) Save it and Change the extention from epub to kepub.epub.
I don't have much trouble so far. Do you have any suggestions to convert files to kepub.epub manually? Thank you very much in advance.