Converting to EPUB results in files that Calibre can't read

Sheeba · 01-20-2020, 05:49 AM

When I convert AZW files to EPUB, Calibre throws an error when I try to open them:

-------------------------------------------------------------------

Spoiler:

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I also can't open those EPUB files in Microsoft Edge either - *however*, I can open them just fine on Android.

So what is Calibre doing that's not standard, and how can I make these EPUB files universally openable?

theducks · 01-20-2020, 11:33 AM

you are blaming Calibre for choking on a a file with a defect
( XMLSyntaxError: Char 0x0 out of allowed range, line 21, column 50 (line 21) ) << FWIW that is a NUL, and has no useful purpose in any ebook

It is a fairly well known fact that many render engines tolerate some defects (because they are so stupidly common

), including the viewer used with Calibre or Sigil. Which is the reason we tell folk VALIDATE to EPUB standards and not rely on 'it worked in Calibre'

Sheeba · 01-20-2020, 12:22 PM

Okay, so that being the case, how do I validate a file to EPUB standards?

I don't see an obvious method of doing that in Calibre.

jbacelar · 01-20-2020, 02:23 PM

1- Install the Run EpubCheck plugin.
2- Open the epub in the editor.
3- Run the plugin.

BetterRed · 01-20-2020, 04:10 PM

If the viewer won't read the EPUB it's possible the editor won't either

In that case the OP can use the stand alone version of EPUBCHECK ==>> Releases · w3c/epubcheck

It needs Java (as do the calibre and sigil plugins).

BR

JSWolf · 01-20-2020, 04:14 PM

Quote:

Originally Posted by Sheeba

When I convert AZW files to EPUB, Calibre throws an error when I try to open them:

-------------------------------------------------------------------

Spoiler:

-------------------------------------------------------------------

I also can't open those EPUB files in Microsoft Edge either - *however*, I can open them just fine on Android.

So what is Calibre doing that's not standard, and how can I make these EPUB files universally openable?

Where did these eBooks come from and can you give us some of the titles? Thanks.

BetterRed · 01-20-2020, 04:15 PM

Quote:

Originally Posted by theducks

you are blaming Calibre for choking on a a file with a defect

Blaming calibre seems reasonable to me, given that the EPUB was created by a calibre AZW3->EPUB conversion.

BR

kovidgoyal · 01-20-2020, 09:34 PM

That looks like some metadata from the mobi file has null bytes in it. calibre tries to sanitize all such but I might have missed something. Open a bug report and attach the aw3 file.

01-20-2020, 05:49 AM	#1
Sheeba Junior Member Posts: 2 Karma: 10 Join Date: Jan 2020 Device: none	Converting to EPUB results in files that Calibre can't read When I convert AZW files to EPUB, Calibre throws an error when I try to open them: ------------------------------------------------------------------- Spoiler: calibre, version 4.8.0 ERROR: Loading book failed: Failed to open the book at C:\eBdata\Test.epub. Click "Show details" for more info. Traceback (most recent call last): File "site-packages\calibre\gui2\viewer\ui.py", line 371, in _load_ebook_worker File "site-packages\calibre\gui2\viewer\convert_book.py", line 234, in prepare_book File "site-packages\calibre\gui2\viewer\convert_book.py", line 191, in do_convert ConversionFailure: Failed to convert book: C:\eBdata\Test.epub with error: Traceback (most recent call last): File "site-packages\calibre\customize\ui.py", line 428, in get_file_type_metadata File "site-packages\calibre\customize\builtins.py", line 194, in get_metadata File "site-packages\calibre\ebooks\metadata\epub.py", line 238, in get_quick_metadata File "site-packages\calibre\ebooks\metadata\epub.py", line 219, in get_metadata File "site-packages\calibre\ebooks\metadata\opf.py", line 43, in get_metadata File "site-packages\calibre\ebooks\metadata\utils.py", line 46, in parse_opf File "site-packages\calibre\utils\xml_parse.py", line 31, in safe_xml_fromstring File "src/lxml/etree.pyx", line 3222, in lxml.etree.fromstring File "src/lxml/parser.pxi", line 1877, in lxml.etree._parseMemoryDocument File "src/lxml/parser.pxi", line 1758, in lxml.etree._parseDoc File "src/lxml/parser.pxi", line 1068, in lxml.etree._BaseParser._parseUnicodeDoc File "src/lxml/parser.pxi", line 601, in lxml.etree._ParserContext._handleParseResultDoc File "src/lxml/parser.pxi", line 711, in lxml.etree._handleParseResult File "src/lxml/parser.pxi", line 640, in lxml.etree._raiseParseError XMLSyntaxError: Char 0x0 out of allowed range, line 21, column 50 (line 21) InputFormatPlugin: EPUB Input running on C:\eBdata\Test.epub Failed to run pipe worker with command: from calibre.srv.render_book import viewer_main; viewer_main() Python function terminated unexpectedly Char 0x0 out of allowed range, line 21, column 50 (line 21) (Error Code: 1) Traceback (most recent call last): File "site.py", line 114, in main File "site.py", line 88, in run_entry_point File "site-packages\calibre\utils\ipc\worker.py", line 189, in main File "<string>", line 1, in <module> File "site-packages\calibre\srv\render_book.py", line 848, in viewer_main File "site-packages\calibre\srv\render_book.py", line 841, in render_for_viewer File "site-packages\calibre\srv\render_book.py", line 816, in render File "site-packages\calibre\ebooks\oeb\iterator\book.py", line 64, in extract_book File "site-packages\calibre\customize\conversion.py", line 246, in __call__ File "site-packages\calibre\ebooks\conversion\plugins\epub_in put.py", line 285, in convert File "site-packages\calibre\ebooks\metadata\opf2.py", line 589, in __init__ File "site-packages\calibre\ebooks\metadata\utils.py", line 46, in parse_opf File "site-packages\calibre\utils\xml_parse.py", line 31, in safe_xml_fromstring File "src/lxml/etree.pyx", line 3222, in lxml.etree.fromstring File "src/lxml/parser.pxi", line 1877, in lxml.etree._parseMemoryDocument File "src/lxml/parser.pxi", line 1758, in lxml.etree._parseDoc File "src/lxml/parser.pxi", line 1068, in lxml.etree._BaseParser._parseUnicodeDoc File "src/lxml/parser.pxi", line 601, in lxml.etree._ParserContext._handleParseResultDoc File "src/lxml/parser.pxi", line 711, in lxml.etree._handleParseResult File "src/lxml/parser.pxi", line 640, in lxml.etree._raiseParseError File "<string>", line 21 lxml.etree.XMLSyntaxError: Char 0x0 out of allowed range, line 21, column 50 ------------------------------------------------------------------- I also can't open those EPUB files in Microsoft Edge either - however, I can open them just fine on Android. So what is Calibre doing that's not standard, and how can I make these EPUB files universally openable? Last edited by theducks; 01-20-2020 at 11:26 AM. Reason: addes SPOILER tags

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01-20-2020, 11:33 AM	#2
theducks Well trained by Cats Posts: 31,270 Karma: 61916422 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	you are blaming Calibre for choking on a a file with a defect ( XMLSyntaxError: Char 0x0 out of allowed range, line 21, column 50 (line 21) ) << FWIW that is a NUL, and has no useful purpose in any ebook It is a fairly well known fact that many render engines tolerate some defects (because they are so stupidly common ), including the viewer used with Calibre or Sigil. Which is the reason we tell folk VALIDATE to EPUB standards and not rely on 'it worked in Calibre'

01-20-2020, 12:22 PM	#3
Sheeba Junior Member Posts: 2 Karma: 10 Join Date: Jan 2020 Device: none	Okay, so that being the case, how do I validate a file to EPUB standards? I don't see an obvious method of doing that in Calibre.

01-20-2020, 02:23 PM	#4
jbacelar Interested in the matter Posts: 421 Karma: 426094 Join Date: Dec 2011 Location: Spain, south coast Device: Pocketbook InkPad 3	1- Install the Run EpubCheck plugin. 2- Open the epub in the editor. 3- Run the plugin.

01-20-2020, 04:10 PM	#5
BetterRed null operator (he/him) Posts: 22,025 Karma: 30277294 Join Date: Mar 2012 Location: Sydney Australia Device: none	If the viewer won't read the EPUB it's possible the editor won't either In that case the OP can use the stand alone version of EPUBCHECK ==>> Releases · w3c/epubcheck It needs Java (as do the calibre and sigil plugins). BR

01-20-2020, 09:34 PM	#8
kovidgoyal creator of calibre Posts: 45,610 Karma: 28549044 Join Date: Oct 2006 Location: Mumbai, India Device: Various	That looks like some metadata from the mobi file has null bytes in it. calibre tries to sanitize all such but I might have missed something. Open a bug report and attach the aw3 file.

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