Ebook formats

[elf]

Random info-ish post.

Ebooks come in approximately 4,312 formats, of which approximately 4,300 are considered obsolete by most people who deal with ebooks today.

Some of the remainder:

Multi-Device Formats:
.LIT: Microsoft Reader format. Free download, but requires registration--you link the software to your hardware. Works on Windows machines, and Windows CE mobile devices, like the Pocket PC.
Microsoft also sells plenty of ebooks in .LIT format. They are DRM'd. The DRM is crackable. LIT is one of the easiest formats to convert from.

.MOBI, .PRC Mobipocket format. Usable with Mobipocket's software; installable on Windows, Palm OS devices, and several dedicated ebook readers, including the Kindle, Cybook, Hanlin and iRex readers. Possibly the most common ebook format. (I don't like it. Probably irrational prejudice; when I got my Clié running, I looked at Mobi & eReader, and I liked eReader's UI better.)

.PDB, eReader type: For Windows, Mac, Unix, Palm OS devices, iPhone, & Blackberry. Free download; they used to have a free simple version & "pro" version for money; they eventually gave up charging for software and gave everyone the "pro" version for free. This one was pushed as a mobile device ebook format, but it hasn't been adopted by any of the e-Ink readers. It is, however, excellent for the early mobile devices--its compression is better than .txt files, and it does allow some formatting (bold, italics, pictures up to a certain size, centered text, etc.) AFAIK, currently only sold at Fictionwise.com, in both secured (DRM'd) and nonsecured versions. However, Palmdoc PDB files are readable by eReader software, and those are available on a number of free ebook sites, especially older ones. (Palmdoc PDBs don't contain any formatting.)

.EPUB, an open-source ebook format. Based on HTML/XHTML. An ePub book is just a .zip file that's been renamed to .epub--and has the right pieces inside to let an ebook reader recognize it. Currently used by the Hanlin and the Sony Readers (with a firmware upgrade), and readable with Adobe Digital Editions and a few other programs. Often claimed to be the One True Ebook Format that can end all the conflicts if everyone would just adopt it. Problems: Many ebook stores that sell ePub don't distinguish it from PDFs, since they assume you'll be reading either with the same software.

.PDF, the one everyone knows. Designed as a print-interface format, to replace the nuisance of postscript files. PDFs are page-based, which is good when you're designing a magazine or flyer, and lousy when you're designing a novel. Most ebook readers support them, with some problems... PDFs are different depending on what program they were made from. PDFs that are scanned pages are just images, usually tifs or jpgs, with enough PDF encoding to allow PDF readers to see them. The filesizes are huge, and navigability is annoying. PDFs converted from Word are often letter/A4 size pages, which look very tiny on a 6" reader. (Palm OS machines reflowed the text--you got the content & lost the formatting.) Some of the ebook readers reflow the text for easier reading (lose formatting); others allow you to zoom in, which means tracking all over the page to read it. There are no good fixes to this, except to convince publishers to release their "free promo ebook" versions in other formats as well.

Single-Device formats:
.IMP, for the eBookwise. Not planning on listing a lot of single-device formats, but this one stands out--it's been around a long time, and the eBookwise is one of the oldest (and cheapest) ebook readers still being sold.

.LRF, for the Sony Readers. Can be created with Sony's software, or with Calibre, free open-source software that's being actively developed. .LRF files can be read on computers with Calibre (or Sony's software, which only works on Windows) and Sony Readers. Books from the Sony store are .LRX, which is DRM'd; it's one of the only ebook formats that hasn't been cracked yet.

.AZW, for the Kindle. Stands out as "the format you can't make yourself." To create a Kindle file, you send your content to Amazon, and they send you back a Kindle file. Sites other than Amazon that offer "Kindle ebooks" generally mean they offer .Mobi/.PRC books, which the Kindle reads. AZW is basically Mobi with a twist; .TPZ is their other format, "Topaz," which is considerably more troublesome.

Palm/Mobile Device Formats:
All Palm OS formats are .PRC or .PDB, because those are the only filetypes recognized by the OS. Ebooks need to be identified by program, not just file extension. Memoware.com has a huge collection of free palm ebooks.

Palmdoc (Simple text-only format; widely readable by many free programs.)
Tealdoc
TomeRaider
Plucker
iSilo
... And more. Lots more. Everyone got into the ebook game at some point, and decided to make their own proprietary format so all future ebooks would have to buy their software. Or at least, that seems to have been the thought, before the Open Source Software movement caught on. They all have their pluses and minuses, which are of interest only to Palm geeks, and their biggest minus is that none of them made it to the e-Ink markets. (Wait, I stand corrected. The Cybook & Hanlin 3 can read Palmdocs. Since Palmdocs are easily convertable, and contain no formatting, this is rather a "so what?" situation.) The (relative) demise of these formats is part of why the active ebook community often pushes for ePub as a standard format--because we'd like one that still works ten years from now, one that people can still put in their readers after today's hot flash companies dissolve.

Comments

[amalthia]

I love your guide! Is it okay if I link to it in multiple places???

[elf]

Sure! I like the Mobileread list, but it doesn't tell you what's actively in use.

[amalthia]

Your information post made so much sense. I feel like anytime an author asks "Doc or PDF?" I should just point them to your list. :) Um and it's useful for all sorts of other questions people have for ebook formats.

[quivo]

This is a great, descriptive guide :). I especially appreciate the notes about .epub-- I've been trying, this weekend, to look into a way of switching to .epub as my primary purchased format instead of .azw so Amazon gets none of my money there, and Adobe Digital Editions has been the primary bottleneck. To strip any .epub purchases of DRM, I have to open it there first, and it's already begun doing that "update, or you can't use this program" bullshit, and I haven't yet been able to find out if this update breaks the DRM-stripping option I have :(.

[elf]

I remember the upgrade being brought up at Mobileread; I can't remember if any useful conclusions were reached. This thread talks about the DRM fix; the related PDF thread talks about upgraded versions starting on page 19.

(I haven't registered ADE, because I'm not willing to buy DRM'd ebooks, so I haven't tried any of the fixing scripts.)

[quivo]

Thanks for the links! Skimming didn't bring me anything, alas. I think I'll just have to continue in the Kindle pen for now :P. Or at least until I have the time and energy to try out the whole process regardless of the risks.

[fallia]

Thank you so much for posting this. I just recently got a WinMo phone and now that I am looking for books to put on it I am always confused by the available file types. This is helpful to have all in one place!

[stormcloude]

So I have a weird question. If ePub are just renamed zip files, can they be renamed back and cleaned up to convert to other formats?

[elf]

YES!... if it's not a DRM'd epub. Unzipping the DRM'd type gets you useless scrambled info.

EPubs can be created from raw HTML and, umm, that other stuff (CSS? Metadata files that I don't understand at all?) and several people do exactly that. EPubs can be unzipped, have the CSS & metadata changed, re-zipped, change the extension back to .epub, and read with the new settings.

It's one of the reasons ePub is being pushed as *the* ebook format; non-DRM'd files are entirely end-user adjustable.

[stormcloude]

Well, yippee! I was thinking that ePub were out of the realm of possiblility for my ebookwise, but it seems not! (My reader likes html!)

[elf]

There's a hangup with it--epubs are normally done as 1 html file/chapter, with a metadata file connecting them all together. (In part 'cos they can; in part 'cos some software--Sony's, I don't know about others) doesn't allow more than 300kb/section.)

So they don't convert neatly to .imp; you have to consolidate the html files somehow. But yeah, the content is all accessible.

[stormcloude]

*nods* Okay. Thank you for the info!

[(Anonymous)]

I love your icon btw

Content of epub/zip files?

[(Anonymous)]

So an epub file is a zipped collection of related html files?

Re: Content of epub/zip files?

[elf]

Yes, and a bit of metadata to make it work.

You can download an epub from Project Gutenberg or Smashwords, change the extension from .epub to .zip, and unzip to see how it's put together.

[(Anonymous)]

Thanks for this list. Its interesting whats out there. I use a Sony and only buy epub, if its not on epub I don't have it, simple as that.

[ex_moondancer561]

There's a wonderful application called Calibre that I highly recommend - it will convert from a number of formats to epub.

(In fact, I wound up at this post from reading a help file there...small world, Elf.)

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[(Anonymous)]

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