converting pdf to epub results in much larger file

mediocre · 04-19-2022, 11:24 AM

Converted a 75MB pdf to epub and the resulting file is 190MB.

Is this expected? What can I do make the epub have the same size? Why is it so much bigger? It is only images since it is a comic.

theducks · 04-19-2022, 12:42 PM

PDF is a Paste Up type language.
Each and every item is 'placed' in a designated position on tree page.
While a conversion TO PDF will most likely be linear (top, down). So each item now has PLACE HERE instructions. Calibre conversion does not optomize the code. (it is a LOT of work any way you go.)

A PDF item can be in any order IN THE SOURCE. This is why PDF is a terrible Source.
The creator may place images on the page, then come back and lay down text. then do edits

Artifacts are Dropcaps, fleurons and other images any place in the (page under conversion) EPUB

mediocre · 04-19-2022, 03:30 PM

Thanks for your response. I am not familiar with how epub works so bare with me. Would it help to create the epub from png files instead? And if yes, can that be done with calibre and how?

BetterRed · 04-19-2022, 07:19 PM

@mediocre - see Read this before Posting PDF Questions

Rather than trying to convert PDF to EPUB directly, you might want to try opening the PDF in MS Word or LO Writer, saving it as DOCX and converting that to EPUB. If the PDF was produced by a word processor that route can often produce surprisingly good results.

BR

salamanderjuice · 04-19-2022, 07:49 PM

Quote:

Originally Posted by mediocre

Thanks for your response. I am not familiar with how epub works so bare with me. Would it help to create the epub from png files instead? And if yes, can that be done with calibre and how?

No, but Kindle Comic Converter can. Despite the name it will make ePubs from a bunch of image files or a CBZ/CBR. Will also make Kindle files obviously.

mediocre · 04-22-2022, 05:18 AM

Thanks for the hint @salamanderjuice. Installed Kindle Comic Converter via homebrew on macOS 12.3.1 and managed to convert from png to epub.

Resulting file is 103MB instead of the previous 200MB. Thank you.

mediocre · 04-22-2022, 05:24 AM

However, the order of the pages seems random. The source folders are

Book/Chapter 1/File1.png
Book/Chapter 1/File2.png
Book/Chapter 2/File3.png
Book/Chapter 2/File4.png
...

The output is in reverse order in manga mode. Basically this is https://github.com/ciromattia/kcc/issues/351
Disabling manga mode resolves this.

04-19-2022, 11:24 AM	#1
mediocre Junior Member Posts: 9 Karma: 10 Join Date: Apr 2022 Device: none	converting pdf to epub results in much larger file Converted a 75MB pdf to epub and the resulting file is 190MB. Is this expected? What can I do make the epub have the same size? Why is it so much bigger? It is only images since it is a comic.

04-22-2022, 05:24 AM	#7
mediocre Junior Member Posts: 9 Karma: 10 Join Date: Apr 2022 Device: none	However, the order of the pages seems random. The source folders are Book/Chapter 1/File1.png Book/Chapter 1/File2.png Book/Chapter 2/File3.png Book/Chapter 2/File4.png ... The output is in reverse order in manga mode. Basically this is https://github.com/ciromattia/kcc/issues/351 Disabling manga mode resolves this. Last edited by mediocre; 04-22-2022 at 05:28 AM.

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04-19-2022, 12:42 PM	#2
theducks Well trained by Cats Posts: 31,037 Karma: 60358908 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	PDF is a Paste Up type language. Each and every item is 'placed' in a designated position on tree page. While a conversion TO PDF will most likely be linear (top, down). So each item now has PLACE HERE instructions. Calibre conversion does not optomize the code. (it is a LOT of work any way you go.) A PDF item can be in any order IN THE SOURCE. This is why PDF is a terrible Source. The creator may place images on the page, then come back and lay down text. then do edits Artifacts are Dropcaps, fleurons and other images any place in the (page under conversion) EPUB

04-19-2022, 03:30 PM	#3
mediocre Junior Member Posts: 9 Karma: 10 Join Date: Apr 2022 Device: none	Thanks for your response. I am not familiar with how epub works so bare with me. Would it help to create the epub from png files instead? And if yes, can that be done with calibre and how?

04-19-2022, 07:19 PM	#4
BetterRed null operator (he/him) Posts: 21,715 Karma: 29711016 Join Date: Mar 2012 Location: Sydney Australia Device: none	@mediocre - see Read this before Posting PDF Questions Rather than trying to convert PDF to EPUB directly, you might want to try opening the PDF in MS Word or LO Writer, saving it as DOCX and converting that to EPUB. If the PDF was produced by a word processor that route can often produce surprisingly good results. BR

04-22-2022, 05:18 AM	#6
mediocre Junior Member Posts: 9 Karma: 10 Join Date: Apr 2022 Device: none	Thanks for the hint @salamanderjuice. Installed Kindle Comic Converter via homebrew on macOS 12.3.1 and managed to convert from png to epub. Resulting file is 103MB instead of the previous 200MB. Thank you.

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