Calibre - convert html to epub

yrings · 04-30-2025, 12:18 AM

I'm trying to convert this project gutenberg html to epub (they have their own, but I didn't like some formatting stuff - I'll probably just use theirs b/c I can't figure this out).
I assumed that nothing would be easier than converting html to epub - epub is already basically html. But - when I import the html (gui) and view / convert - I see HTML. It doesn't parse the HTML. I tried setting the html to zip encoding setting, didn't change anything.
I tried converting using the command line - it seemed to be parsing, but crashed because it couldn't split up the html file into small parts, and I couldn't figure out how to tell it "use the h2 tags!"

I first tried with an older version (I think 6.something) before downloading the latest (is it 8.3?)

So -

1 - how can I convert html to epub using the GUI?
2 - how can I tell the cli to split the epub parts based on h2 tags?

Spoiler:

DNSB · 04-30-2025, 01:13 AM

I imported the html file and it imported as a .zip which is normal for HTML import. I then converted to ePub3 and no errors though the output ePub code looks pretty ugly and the cover file needed a manual download and attach. The ePub 3 downloaded looked a lot better so I did a quick mark/split* in Sigil and have attached the result. Ghod alone knows why they have image and no image versions since the only image seems to be the cover image.

*
Search <h2
Replace <hr class="sigil_split_marker" /> <h2

Quoth · 04-30-2025, 08:19 AM

Better to use the Gutenberg epub and convert with rules (automatic).

yrings · 04-30-2025, 10:15 AM

Thank you all for your help and advice.
I'm more curious why html convert wasn't working for me, but I don't have a practical need anymore, so I'm going to mark this as fixed.

04-30-2025, 12:18 AM	#1
yrings Junior Member Posts: 2 Karma: 10 Join Date: Apr 2025 Device: kindle scribe	Calibre - convert html to epub I'm trying to convert this project gutenberg html to epub (they have their own, but I didn't like some formatting stuff - I'll probably just use theirs b/c I can't figure this out). I assumed that nothing would be easier than converting html to epub - epub is already basically html. But - when I import the html (gui) and view / convert - I see HTML. It doesn't parse the HTML. I tried setting the html to zip encoding setting, didn't change anything. I tried converting using the command line - it seemed to be parsing, but crashed because it couldn't split up the html file into small parts, and I couldn't figure out how to tell it "use the h2 tags!" I first tried with an older version (I think 6.something) before downloading the latest (is it 8.3?) So - 1 - how can I convert html to epub using the GUI? 2 - how can I tell the cli to split the epub parts based on h2 tags? Spoiler: ~/calibre-bin/calibre/ebook-convert ./sholom_aleichim\ jewish\ children.html sholom.epub --chapter-mark pagebreak --level1-toc "h2" Conversion options changed from defaults: level1_toc: 'h2' 1% Converting input to HTML... InputFormatPlugin: HTML Input running on /home/username/Downloads/sholom_aleichim jewish children.html Language not specified Creator not specified Building file list... Normalizing filename cases Rewriting HTML links 34% Running transforms on e-book... Merging user specified metadata... Detecting structure... Auto generated TOC with 0 entries. Flattening CSS and remapping font sizes... Stylesheet 'resource://content-accessible/viewsource.css' referenced by file 'sholom_aleichim%20jewish%20children.html' not in manifest Source base font size is 12.00000pt Removing fake margins... Cleaning up manifest... Trimming unused files from manifest... Creating EPUB Output... 67% Running EPUB Output plugin Splitting markup on page breaks and flow limits, if any... Looking for large trees in sholom_aleichim%20jewish%20children.html... Found large tree #0 Traceback (most recent call last): File "runpy.py", line 198, in _run_module_as_main File "runpy.py", line 88, in _run_code File "site.py", line 47, in <module> File "site.py", line 43, in main File "calibre/ebooks/conversion/cli.py", line 429, in main File "calibre/ebooks/conversion/plumber.py", line 1267, in run File "calibre/ebooks/conversion/plugins/epub_output.py", line 225, in convert File "calibre/ebooks/oeb/transforms/split.py", line 69, in __call__ File "calibre/ebooks/oeb/transforms/split.py", line 78, in split_item File "calibre/ebooks/oeb/transforms/split.py", line 227, in __init__ File "calibre/ebooks/oeb/transforms/split.py", line 359, in split_to_size File "calibre/ebooks/oeb/transforms/split.py", line 352, in split_to_size calibre.ebooks.oeb.transforms.split.SplitError: Could not find reasonable point at which to split: sholom_aleichim%20jewish%20children.html Sub-tree size: 716 KB Last edited by theducks; 04-30-2025 at 12:59 AM. Reason: SPOILER LOG files

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04-30-2025, 08:19 AM	#3
Quoth Still reading Posts: 15,052 Karma: 111120239 Join Date: Jun 2017 Location: Ireland Device: All 4 Kinds: epub eink, Kindle, android eink, NxtPaper	Better to use the Gutenberg epub and convert with rules (automatic).

04-30-2025, 10:15 AM	#4
yrings Junior Member Posts: 2 Karma: 10 Join Date: Apr 2025 Device: kindle scribe	Thank you all for your help and advice. I'm more curious why html convert wasn't working for me, but I don't have a practical need anymore, so I'm going to mark this as fixed.

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