MOBI -> EPUB conversion removes scene breaks

[tlangner]

Hey guys,

I have a couple of eBooks in MOBI format here and I want to convert into the EPUB format since my eBook Reader handles this in a better way. I use the default settings for the conversion except that I check "Remove spacing between paragraphs" in the "Look & Feel" section of the conversion dialog. The resulting EPUB is fine and has only one -- for my taste -- rather annoying issue: all scene breaks are gone and there does not seem to be a visual difference between an ordinary paragraph and a scene break paragraph.

I enabled the debug output to analyse this problem further and it looks that the issue is introduced during the final processing step. More precisely, when I open the HTML file in the folder "structure", a scene break looks as follows:

<p class="calibre_132">blablabla</p>
<p class="calibre_119">blablabla</p>

and the style "calibre_119" contains "margin-top: 2em;" while "calibre_132" does not. Opening the HTML file also shows properly formatted scene breaks.

Viewing the HTML file in the folder "processed" yields the following code for the same part as above:

<p class="calibre17">blablabla</p>
<p class="calibre17">blablabla</p>

Apparently, the two different styles have been merged into the same one and consequently, the HTML file does not exhibit any scene breaks.

Is this a bug in Calibre or is there any setting that helps to retain the scene breaks during the processing step? I already played around with the "Heuristic Processing" settings, but neither of them turned out to help.

Thanks for your help in advance, cheers,

Tobias

PS: I do not attach the respective MOBI file here since it is DRM restricted. If necessary, I can send it by PM though.

[ldolse]

This isn't a bug - these scene breaks are set using CSS, as you noted, and you enabled the 'remove spacing between paragraphs' option. That feature is essentially a giant hammer which zeroes all the css relating to paragraph spacing (as it's documented to do). Just disable that feature and use Tweak ePub or Sigil to manually edit the css after conversion to eliminate the spacing between normal paragraphs (calibre119 in your example).

Heuristics can't help here, it's looking for other types of scene break data that often gets screwed up from other conversion processes, but it doesn't check css.

[tlangner]

Thanks a lot for your answer, it indeed explains the issue.

Though not being a bug, shouldn't it be possible to remove the spaces between ordinary paragraphs and not within different scenes without having to manually edit the CSS file? This is particular inconvenient when you have to do it for multiple files (in my case for all in my library) because the respective styles have different IDs for different books, so it is quite hard to automate the task. It would be nice if calibre provided an option to do this...

[ldolse]

Calibre has no idea those spaces are supposed to be scene breaks - it's just a margin. That's one of the issues with ebook design IMHO - traditional HTML design methodologies dictate all layout should be controlled by CSS. This makes sense for Web, but it doesn't really make sense for ebooks - there is no such thing as a 'lossless' ebook conversion, so it's incredibly easy to lose information that is solely defined in css. That's why I define scene breaks as an empty paragraph <p>&nbsp;</p>. Traditional html design says it's a no-no, but this information can't be erased when format-shifting ebooks.

The other issue is the thing that you're asking for, while it would certainly be nice, would be quite difficult to implement. Aside from the heuristics features, Calibre never 'guesses' anything. You'd essentially have to create a heuristic scan across all the css styles in the book AND their usage in the actual text to guess which one(s) might be a scene breaks, and then you'd have to be smart enough to somehow over-ride all the settings that Calibre provides to directly manipulate css. And then of course you'd have to deal with the support nightmare of directly conflicting features and users who don't understand them and leave them all enabled.

You will also find that not all of your ebooks use css - many ebook creators recognize the conundrum I mentioned above and also use empty paragraphs to define scene breaks. The fact that many editors follow that practice means you don't always need to worry about this issue, and it also makes it not really worth the effort for any developer to even consider developing/supporting some sort of heuristic.

[Polly7]

I bought some ebooks from the Black Library in Mobi format, and they came with a ragged left aligned margin. When I reconverted to Mobi and set the justification to full, all the scene breaks disappeared. I don't know what to do as
I am not clever enough where computers are concerned to go advanced.
PLEASE HELP!!!
Polly7

[JSWolf]

Do you have the option to remove blank lines between paragraphs turned on? If so, turn that off. It depends on how the section break was made in the eBook and sometimes it's made such that Calibre cannot tell it's a section break vs a paragraph space.

[Polly7]

Hi there JSWolf,
No, the blank space between paragraph option was off, as was the remove blank spaces between paragraphs. All I did was set the justification to full, and all the scene breaks disappeared.
HELP!!
Polly7

[JSWolf]

Originally Posted by Polly7

Hi there JSWolf,
No, the blank space between paragraph option was off, as was the remove blank spaces between paragraphs. All I did was set the justification to full, and all the scene breaks disappeared.
HELP!!
Polly7

Can you post a non-copyrighted Mobi that shows this problem?