"Best" ebook formats

[Vivan]

I'm the administrator on a largeish (~20,000 users) website based on uploading and downloading ebooks.

Currently we have no official trumping system and as such allow all of the following formats:

PDF
DJVU
CHM
LIT
RTF
HTML
MOBI
TXT
EPUB

I feel that this is too many and there are varying types of each - e.g. a retail PDF vs. a scan vs. an OCR'd scan, obviousy the retail PDF is the highest in the hierarchy.

I'm trying to minimise the number of books in different formats, whilst still retaining enough breadth to allow anyone to find an ebook in a format that they are able to read. I'm considering removing LIT, RTF, HTML, DJVU, CHM and TXT though I don't really know enough about ebook formats/ readers to make that call, which is why I'm here asking you.

I need to find which are the ideal set of formats that would allow maximum breadth without redundancy. The only ones I *know* fall in this set are Retail EPUB, Retail MOBI and Retail PDF. Are there others, or will those three suffice for any ebook reader?

[DaleDe]

Kindle only accepts PDF and MOBI (AZW) files and almost everybody else can read ePUB files. So two should be MOBI and ePub. PDF does not work very well on small mobile screens but is popular so I would call it the 3rd format. TXT is too basic to provide a reasonable reading experience if there is a need for even primitive formating or italics or bold or anything else. A few older PDA's may want LIT but it is now going out of favor. However those devices would also work with eReader format which has a PDB extension but that is not an exclusive extension. You can also read about eBook formats in our wiki.

Dale

[dwig]

MOBI & ePUB will cover all current dedicated ereaders and reading software for at least one of these is available for all other current popular devices and computers with the possible exception of a few phones.

LIT and a number of older formats you don't list are necessary only to support older devices. DJVU, itself, is also a dying format though some of its characteristics are being integrated into the next major rev of ePUB.

PDF is useful primarily on larger display general purpose computers (e.g. desktop and laptop computers). Its not a good ebook format even there, except when dealing with books that require very strict formating and/or special fonts (e.g. technical textbooks, German texts in blackletter, parallel English & Greek texts, ...)

If you need to pare down your list of formats, I would place MOBI and ePUB as the primary keepers with PDF as a last resort format for those special docs that require it. Keeping TXT gives your users access to a format that can be accessed in any wordprocessor for editing or conversion.

While you're researching this, I would suggest that you look at other online libraries with an eye to what formats they offer. Project Gutenberg offers HTML, ePUB, MOBI, Plucker (why?, I don't know), QiOO, and TXT(UTF-8). Project Gutenberg Austrailia offers only TXT and HTML for most titles. The University of Adelaide's ebooks@Adelaide offers only HTML (formatted for web display only) and ePUB (for download).

[DaleDe]

Originally Posted by dwig

While you're researching this, I would suggest that you look at other online libraries with an eye to what formats they offer. Project Gutenberg offers HTML, ePUB, MOBI, Plucker (why?, I don't know), QiOO, and TXT(UTF-8). Project Gutenberg Austrailia offers only TXT and HTML for most titles. The University of Adelaide's ebooks@Adelaide offers only HTML (formatted for web display only) and ePUB (for download).

like any volunteer organization Project Gutenberg offers whatever formats volunteer users are willing to generate. They are not based on any user need study. That is why Plucker is in the list. HTML by itself as an ebook format is terrible, no embedded images, lots of separate files. It is supported primarily since the internals of epub and mobi require similar formatting engines. It is really only ok for web display as you mentioned.

Dale

[DSpider]

TXT is crap. Apart from paragraph indentations you can't style it in any way. Well, actually you can underline words if you use the next immediate line, like this:

TITLE
------

But that's about it... Plain TXT is simply a redundant format for an e-book.

Oh, and ASCII. I forgot about ASCII titles. But it all goes to shit if you change the font.


PDF is good for academic quotes because they can imitate the printed page and page numbers, which the other formats don't have (but they're looking into it). PDF can also be read on the Kindle and everything else; not just MOBI on one/ePUB on everything else. Also, a tagged PDF can be converted with all the proper italics, bold, indentations, etc., in their exact places and it can also, theoretically, reflow on smaller text screens.


ePUB definitely has its advantages, except... It's looks different everywhere you look at it. It's like we're back in 1999 where every webpage looked different depending on which browser you used. We need a standard reading system, not 3 (Adobe ePUB, DRM ePUB and plain ePUB).

http://www.youtube.com/watch?v=YfSNo...layer_embedded