Calibre changes size of cover.jpg when copy to new Libary --> see PDF attached

[icq70610]

Hi folks,

Calibre changes the file size of all covers if copying to a empty library!
Windows 7 32.bit / Calibre 0.7.21

What I did:

1) Create empty library

2) Copy Selection of books into new library

3) Checked filesize of cover.jpg in new library. and compare to old one

I copied approx 1000 + books and filesize changed by +25% also noticeable sometime *.lit files are not copied.

in the PDF you have it with step by step pictures and text

Thanks

Joe

[DoctorOhh]

Originally Posted by icq70610

3) Checked filesize of cover.jpg in new library. and compare to old one

So it didn't change the dimension of the image the the filesize?

[icq70610]

hi no it dosent change the dimensions.

im currently still investigating details but in all files the changes are present.

i extracted the DIFF of the image changes and you can see them attached.

if you look at the compare.jpg you will see the Quality settings changing from 75% --> 92% so it seems calibre is doing a preprocessing of the files before rewriting them.

Thanks

Joe

[kovidgoyal]

yes all covers are processed. Why is that a problem?

[icq70610]

Hi,

basically for two things.

1) why should a copy books to library anyhow do a preprocessing? I was assuming that the copy process is simple a copy and a rename of the directory according to the naming structure.

BOOK TITLE (166) --> BOOK TITLE (23)

2) preprocessing the files and changing quality in jpg's especially when you have a small image increases the filesize without any further info. so I was wondering why my folder size was changing?

Was the whole procedure planned? I mean if there is a good reason why the increase should be there im not against. I just dont see one :-(

thanks for the quick reply.

Joe

[kovidgoyal]

It uses the same code path as adding books, which processes images to normalize them and replace transparent backgrounds with white ones.