Book Compression Inside Calibre?

[johnelle]

As books get bigger and bigger I find myself going to the cloud more and more to compress books so they will squeeze on my wife's kindle. This is tedious because it involves exporting an epub, web compress, reload in calibre, reconvert, etc.

Last I checked this was not available in Calibre via plug-in or otherwise(?)

The web epub compress frequently cuts the size by an order of magnitude which I assume is mostly just adjusting image quality.

Any alternatives?

[retiredbiker]

Originally Posted by johnelle

As books get bigger and bigger I find myself going to the cloud more and more to compress books so they will squeeze on my wife's kindle. This is tedious because it involves exporting an epub, web compress, reload in calibre, reconvert, etc.

Last I checked this was not available in Calibre via plug-in or otherwise(?)

The web epub compress frequently cuts the size by an order of magnitude which I assume is mostly just adjusting image quality.

Any alternatives?

If the book is epub or azw3, open it in the Calibre editor. Two tools to use.

Font manager: get rid of any embedded fonts; they can take up several megabytes if they are present. (Unless you can't live without that font...)

Under Tools-->Compress images losslessly. Check the box for lossy compression and put in a factor like 50. This can reduce jpgs up to 10-fold sometimes. If the images are png, very slow and not so much compression. You won't be able to see the difference on a Kindle.

Also look for advertising images and so on; you can just get rid of them.

Large png images you want to keep, export them and use another tool to convert to jpg, re-import (use replace image on right-click menu) and compress.

Run the bug check, correct errors, and save.

I recently had a book go from 19.1 megabytes down to 0.4.

[JSWolf]

Originally Posted by retiredbiker

If the book is epub or azw3, open it in the Calibre editor. Two tools to use.

Font manager: get rid of any embedded fonts; they can take up several megabytes if they are present. (Unless you can't live without that font...)

Under Tools-->Compress images losslessly. Check the box for lossy compression and put in a factor like 50. This can reduce jpgs up to 10-fold sometimes. If the images are png, very slow and not so much compression. You won't be able to see the difference on a Kindle.

Also look for advertising images and so on; you can just get rid of them.

Large png images you want to keep, export them and use another tool to convert to jpg, re-import (use replace image on right-click menu) and compress.

Run the bug check, correct errors, and save.

I recently had a book go from 19.1 megabytes down to 0.4.

All that is good advice. I do it as well. Also, remove the unused CSS classes. There can be hundreds of unused classes that take up space. I use a compression level of 70 as for most graphics, it makes no noticeable difference.

If you compress Kindle eBooks more then the default, you end up using more battery as it takes more processor to uncompress.

@johnelle, do you have to have so many eBooks on the Kindle?

[theducks]

Shrinking modern HiRes images is the most effective in size reduction.
Getting rid of unused Styles will remove a few hundred bytes.

Combine cases of: P style= Span Style= (.+?) /Span /P that some Word sourced conversions had. Good for speed as well as lose a few KBytes

[johnelle]

Sounds like a great opportunity for a plug-in. Most of the processes described here seem somewhat fussy and time consuming whereas the cloud compress (epubs) mostly takes time with upload/download. A plug-in with limited input needed would be fabulous.

[JSWolf]

Why would you let some cloud service mangle your ePub? That's a bad idea.

I would want to do it by myself so I can see the result.

[theducks]

Molly Wood of CNET had a term she used: Auto-Incorrect

I am with the Wolf ( ) , letting generic tools loose on a really non-generic product (book) is a recipe for a mangle.

Have you really looked at how books end up coded ??

Rules! We are AUTHORS! We don't need no stinking rules stifling our (layout) creativity (or bothering to learn the basics of ebook coding)

[JSWolf]

Originally Posted by theducks

Molly Wood of CNET had a term she used: Auto-Incorrect

I am with the Wolf ( ) , letting generic tools loose on a really non-generic product (book) is a recipe for a mangle.

Have you really looked at how books end up coded ??

Rules! We are AUTHORS! We don't need no stinking rules stifling our (layout) creativity (or bothering to learn the basics of ebook coding)

I've seen the internals of too many KU eBooks and some of them are dreadful. Learn how to make a well coded eBook before you make a dreadfully coded eBook.