View Full Version : Splitting .prc (and .mobi files)

12-12-2010, 06:03 PM
Not sure if this is possible or not, but I have some collected works which I want to split back out into the individual books (the collections aren't following the internal chronology of the series very well which is annoying). The earlier collections are .prc format, the later are .mobi, both fortunately don't have DRM applied.

What I want to do is to open the file, save it as the individual book, and delete the content that is not that book, then repeat the process for each of the books and novellas in that collected file. I looked using TextEdit, but the .prc format doesn't lend itself to that. I could download text versions and modify those, but I want the compression of the .prc files.

Any suggestions? I use a Mac, OX 10.5, reading on an Aluratek Libre.

12-12-2010, 06:48 PM
Basically you'd have to export out to HTML (Mobipocket is really just a modified HTML 3.2 that's compressed) edit out the bits you don't want, and convert it back to Mobi again.

I actually recommend making a proper ePub file from your extracted text and converting that to Mobi. Easier to edit again later without having to go through the entire process all over again.

You can use any number of tools for this: Calibre, MobiPerl (, or Mobiunpack ( (all created by MR forum members, with support threads) to extract, your favourite text editor or a specialized tool like Sigil to re-create the book you want.

And then use Calibre, MobiPerl, or Amazon's KindleGen ( or Kindle Previewer ( app (these last require an Intel Mac w/10.5 or better) to create your new Mobi file (under KindleGen, use the -c2 setting for tightest compression, and the KindleStrip ( python script to get of excess bloat).

Incidentally, if you have access to an ePub or even HTML source for your books, it'd be best to start from that. Tidier and simpler and that's how I've been modifying my Baen and Fictionwise MultiFormat stuff so that it displays the way I want it to on my Kindle.

Hope this helps.

12-12-2010, 07:02 PM
Note that an ePub is a zip file, so if you convert from MOBI to ePub you can unzip the result and edit it as needed. Also, it sounds like all you will need to do is edit the .opf and .ncx files. If you are using Calibre to go back to MOBI, you may even be able to leave the skipped HTML files in place because Calibre will likely prune them.