File size of epub formatted books

Epubber · 01-20-2012, 04:21 PM

When adding duplicate books in epub format to Calibre sometimes only file size differs. Per example I see (both stored in different directories of course):
book.epub 0.2 Mb
book.epub 0.5 Mb
Opening the books in Calibre with E-book Viewer shows no differences. All looks exactly the same: same pictures, same text, same page count etcetera.

Is there anyone who can explain why same books can have different file sizes (as you see sometimes more than doubled!)

And is there a way to compare epub formatted books with each other? So I can check for missing parts (if any)?

Thanks in advance!

CWatkinsNash · 01-20-2012, 04:24 PM

The only thing that comes to mind - are the covers on both the same dimensions? (You should be able to check quickly by hovering over the cover in the edit metadata window.)

theducks · 01-20-2012, 04:24 PM

Quote:

Originally Posted by Epubber

When adding duplicate books in epub format to Calibre sometimes only file size differs. Per example I see (both stored in different directories of course):
book.epub 0.2 Mb
book.epub 0.5 Mb
Opening the books in Calibre with E-book Viewer shows no differences. All looks exactly the same: same pictures, same text, same page count etcetera.

Is there anyone who can explain why same books can have different file sizes (as you see sometimes more than doubled!)

And is there a way to compare epub formatted books with each other? So I can check for missing parts (if any)?

Thanks in advance!

Same Pictures, but maybe different resolution? some viewers scale any input to fit the screen.

Do a Tweak epub on each version, paying attention to the file sizes of the various component pieces (Cancel when done, you don't need to save)

Epubber · 01-20-2012, 04:45 PM

Thank you very much! In this case Tweak epub learned me in some books there are some 'hidden' areas like a "_MACOSX" section with several pictures in it. And these pictures are not saved in both books (maybe these pictures show up when I use a iPad or something?).

Interesting, I will investigate this further.

HarryT · 01-21-2012, 07:04 AM

Another thing to be aware of is that, when you convert a book, Calibre will sometimes resize your image to fit the resolution of your selected output device.

01-20-2012, 04:21 PM	#1
Epubber Junior Member Posts: 2 Karma: 10 Join Date: Jan 2012 Device: prs-t1	File size of epub formatted books When adding duplicate books in epub format to Calibre sometimes only file size differs. Per example I see (both stored in different directories of course): book.epub 0.2 Mb book.epub 0.5 Mb Opening the books in Calibre with E-book Viewer shows no differences. All looks exactly the same: same pictures, same text, same page count etcetera. Is there anyone who can explain why same books can have different file sizes (as you see sometimes more than doubled!) And is there a way to compare epub formatted books with each other? So I can check for missing parts (if any)? Thanks in advance!

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01-20-2012, 04:24 PM	#2
CWatkinsNash IOC Chief Archivist Posts: 3,950 Karma: 53868218 Join Date: Dec 2010 Location: Fruitland Park, FL, USA Device: Meebook M7, Paperwhite 2021, Fire HD 8+, Fire HD 10+, Lenovo Tab P12	The only thing that comes to mind - are the covers on both the same dimensions? (You should be able to check quickly by hovering over the cover in the edit metadata window.)

01-20-2012, 04:45 PM	#4
Epubber Junior Member Posts: 2 Karma: 10 Join Date: Jan 2012 Device: prs-t1	Thank you very much! In this case Tweak epub learned me in some books there are some 'hidden' areas like a "_MACOSX" section with several pictures in it. And these pictures are not saved in both books (maybe these pictures show up when I use a iPad or something?). Interesting, I will investigate this further.

01-21-2012, 07:04 AM	#5
HarryT eBook Enthusiast Posts: 85,544 Karma: 93383043 Join Date: Nov 2006 Location: UK Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6	Another thing to be aware of is that, when you convert a book, Calibre will sometimes resize your image to fit the resolution of your selected output device.