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Old 07-23-2012, 03:52 PM   #18
MisterMax
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Posts: 25
Karma: 7365
Join Date: Jul 2012
Location: Italy
Device: 2 Kobo Touch
Quote:
Originally Posted by Danger View Post
epub is NOT a compression. An epub is just a ZIP file renamed, that's all, nothing more. What makes an epub is what's inside the zip file making up the book.
Yes, I know that ePub is only a zip.
The fact is that if the Zip algorithm compress the single file 1 by 1, so if you have only one big html file, this single file is "more compressible" that the respective part splitted in 25Kb chunk.
Due to that, a "normal" epub generated by calibre will have 260Kb html chunk, and the same epub "optimized" will have about 10 time more smaller html chunk of 25Kb each, and this optimized epub will be bigger, because the zipping algorithm is less efficient.

I also tried variation of zipping algorithm by manually decompressing and recompressing the epub using 7Zip.
I've tried various compression setting (store/compress fastest/ fast/ normal /max / ultra - change word size from 8 to 128 bytes): the size of the compressed epub clearly change, but the page turn speed remain the same.

Quote:
Originally Posted by Danger View Post
As for splitting up the files. Yes you can get some pretty poor spots to split on. Since you are splitting the files inside by size rather than by chapters and the Kobo pagebreaks after every file, you will get pages of text that simply end with a lot of white space at the end but then have the text continue on on the next page. So you could end up with 2 sentences on one page and the rest of the text on the other.
Now I understand, you are right, this happen.
An "optimized" ePub will have more page break.
The biggest book I have turned out to be about 80 "more" page in the "optimized" version (500 vs 580). This is my "worst case" scenario.
For me this is a non-issue, I really doesn't care about page break... but for other people it can be different :-)

Thanks for pointing this out.
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