Convert from epbup to mobi or awz3 - huge size and other questions

[borisov87]

Hi all
I install calibre to ubuntu .
I have epub file and test convert it to mobi and azw3. On setting i change this
Disable font size rescalle - checked
Subset all embeded fonts - checked

results:
original epub - 3.8Mb
mobi - 4.1Mb
azw3 - 4.6Mb

Is this normal?

Who to use - mobi or azw3?
Advantages of mobi is less size.
Please tell me are there any reasons to use azw3 ?

[cybmole]

5mb is not Huge. What are you planning to do with a saved 1mb?
Azw preserves all epub features, mobi does not - but you may not notice the difference.
Make both and compare, if you can spare the huge space

[pdurrant]

Originally Posted by borisov87

results:
original epub - 3.8Mb
mobi - 4.1Mb
aw3 - 4.6Mb

Is this normal?

Yes. ePub uses zip (deflate, I think), while mobi and azw3 use a less efficient compression algorithm.

[borisov87]

Originally Posted by cybmole

5mb is not Huge. What are you planning to do with a saved 1mb?
Azw preserves all epub features, mobi does not - but you may not notice the difference.
Make both and compare, if you can spare the huge space

I upload azw3 and mobi on kindle, but on first time not see any difference - please hint promt me. May be these differences is only when i buy original book from amazon, not conversion. Of course size is not problem ,I reflect theoretically and I'm just curious is there real advantages of awz3 over mobi

And see mobi have big images from left to right - epub(original), mobi, azw3

[borisov87]

Ok i see from where come difference.
On left right click -> inspect see
epub and azw3 have same css

.calibre3 {
height: auto;
width: 82%;
}

mobi have different

img[Attributes Style] {
height: 608px;
width: 431px;
}

Same for text epub -> mobi is 1:1 on css see font size , font family, margins and etc is same, but epub is other basic and not save original formatting.

cybmole -
Thanks for the info, after a detailed examination, I saw that there is a big difference beetwen mobi and azw3. azw3 save all from epub 1:1. Mobi lost more features from epub and not preserve it.