Calibre cant add djvu files with proper book cover

loviedovie · 05-24-2015, 12:05 AM

Hi

I have bunch of djvu files and I added them to Calibre. None of them have covers in Calibre. However pdf files are ok. Is this a limitation?

You can find some sample files from archive.org

thanks

kovidgoyal · 05-24-2015, 12:08 AM

calibre only supports djvu files that contain text. Not files that are collections of images.

BobC · 05-25-2015, 06:30 AM

The text layer of DJVU files from Archive.org is usually a raw OCR scan intended for locating text on the image layer.

My experience of it is that it is relatively poor as a source for an e-book without extensive editing by eyeball comparison with the image text.

On the books I have worked on this way I've imported the OCR'd text layer to LibreOffice Writer then edited that on one PC while viewing the DJVU Image on another. Only when happy with the edited text version have I converted it to EPUB for input to Calibre. Doing the sort of text manipulation needed to clean up such poor OCR scan text needs a proper Word Processor.

BobC

Geremia · 12-10-2022, 03:21 PM

See the djvu-covers plugin or the more recent calibre_djvu_covers (which only requires ImageMagick's 𝚌𝚘𝚗𝚟𝚎𝚛𝚝 command).
Calibre should be able to do DjVu cover generating in-house. I'm really surprised it doesn't.

05-24-2015, 12:05 AM	#1
loviedovie Addict Posts: 295 Karma: 2139988 Join Date: Nov 2014 Device: bookeen	Calibre cant add djvu files with proper book cover Hi I have bunch of djvu files and I added them to Calibre. None of them have covers in Calibre. However pdf files are ok. Is this a limitation? You can find some sample files from archive.org thanks

12-10-2022, 03:21 PM	#4
Geremia Addict Posts: 238 Karma: 100000 Join Date: Oct 2012 Device: Calibre	djvu-covers plugin See the djvu-covers plugin or the more recent calibre_djvu_covers (which only requires ImageMagick's 𝚌𝚘𝚗𝚟𝚎𝚛𝚝 command). Calibre should be able to do DjVu cover generating in-house. I'm really surprised it doesn't. Last edited by Geremia; 12-10-2022 at 03:34 PM.

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05-24-2015, 12:08 AM	#2
kovidgoyal creator of calibre Posts: 44,145 Karma: 22670164 Join Date: Oct 2006 Location: Mumbai, India Device: Various	calibre only supports djvu files that contain text. Not files that are collections of images.

05-25-2015, 06:30 AM	#3
BobC Guru Posts: 691 Karma: 3026110 Join Date: Dec 2008 Location: Lancashire, U.K. Device: BeBook 1, BeBook Pure, Kobo Glo, (and HD),Energy Sistem EReader Pro +	The text layer of DJVU files from Archive.org is usually a raw OCR scan intended for locating text on the image layer. My experience of it is that it is relatively poor as a source for an e-book without extensive editing by eyeball comparison with the image text. On the books I have worked on this way I've imported the OCR'd text layer to LibreOffice Writer then edited that on one PC while viewing the DJVU Image on another. Only when happy with the edited text version have I converted it to EPUB for input to Calibre. Doing the sort of text manipulation needed to clean up such poor OCR scan text needs a proper Word Processor. BobC

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