Mobi File Size

[schacon]

So the .mobi format is pretty big, weighing in at about 85M as opposed to 25-30M for the other formats, most of which are big images. I just pngcrushed them, which brought them down 10M (from 35-40M), but the .mobi file is apparently always going to be 3x bigger because of how Amazon's kindlegen tool works:

From http://forum.atlas.oreilly.com/t/non-unicode-arial-ttf-file-option/20/4:

Generally, MOBI files are around 2-3 times the size of the corresponding EPUB, because we use Amazon's kindlegen tool to generate EPUB from MOBI (the only tool officially endorsed for this purpose), and kindlegen requires three copies of the ebook content to be archived in each MOBI file: the original EPUB source, a legacy MOBI7 version of the content for older-model Kindle devices, and a KF8 version of the content for Kindle devices/apps that support the latest Kindle formatting specs. When MOBI files are posted to Amazon for sale, Amazon will serve the appropriate version of the content to customers, based on the device to which they're downloading the file, so the file size will ultimately be smaller again on the Kindle device/app.

So, the question is if this format is really even useful to us. If Kindles generally support ePub and PDF now should I even be putting .mobi files on the site at all, since they're optimized for Amazon upload and not for this purpose. Or maybe there is a way to pull the KF8 format out separately for that purpose?

[harupong]

Before commenting, let me say "Congratulation" for releasing Pro Git2. Great work!!

As for ebook formats, I think .mobi/.azw will be highly appreciated by Kindle owners(myself included) because

a) ePub is not supported on Kindle(neither devices nor app), except the Kindle Fire tablets where other third party apps support it, and

b) they're reflowable unlike PDF.

The table below shows some of the numbers I gathered from http://progit-ja.github.io/ , where I've provided Japanese version of "Pro Git 1" ebooks. latex/makepdf, Calibre's command line tool, and Rakefile provided at progit/progit are used to generate those files.

format	% of all downloads	file size
pdf	70%	4.5MB
epub	14%	4.0MB
azw	11%	4.4MB
mobi	5%	3.0MB

Mobi is the smallest among these formats. Calibre must be doing something special for that, I suppose.

[schacon]

OK, by limiting the size of the images I was able to get the file sizes to about 12-15M for PDF,ePub and a bit under 25M for Mobi, which is emailable and way under the 50M Kindle Uploader limit. This should do for now.