EPUB3 Already Marginalized?
Written by Sue Gee   
Monday, 31 October 2011

The EPUB3 specification, the major revision to the IDPF's standard interchange and delivery format for eBooks was officially finalized this month. But have Amazon and Apple already relegated it to the status of a minor player?

EPUB is the International Digital Publishing Forum's distribution and interchange format for digital publications and documents. It defines a means of representing, packaging and encoding structured and semantically enhanced Web content, including HTML5, CSS, SVG, images, and other resources, in a single-file format.


EPUB has been widely adopted as the standard for eBooks and the latest version of the specification, which has been in preparation since May 2010 is intended to support a wider range of publication requirements, including complex layouts, rich media and interactivity, and global typography features.


EPUB 3 is a set of four specifications

  • EPUB Publications 3.0 defines publication-level semantics and conformance requirements

  • EPUB Content Documents 3.0  defines profiles of XHTML, SVG and CSS for use in EPUB Publications.

  • EPUB Open Container Format (OCF) 3.0  defines a file format and processing model for encapsulating a set of related resources into a single-file (ZIP) EPUB Container.

  • EPUB Media Overlays 3.0 defines a format and a processing model for synchronization of text and audio.

Based on HTML5, EPUB 3 adds support for rich media (audio, video), interactivity (JavaScript), global language support (including vertical writing), styling and layout enhancements, SVG, embedded fonts, expanded metadata facilities, MathML, and synchronization of audio with text and other enhancements for accessibility.

It was hoped that finalization of the new standard would pave the way for a new generation of enhanced ebooks. However, the announcement last week of Kindle Format 8 has already delivered a blow to EPUB3. It had been hoped that the arrival of EPUB3 would persuade Amazon into supporting EPUB - instead Amazon has its own, possibly incompatible, format for achieving the same results.

Martin Taylor, who operates a digital publishing consultancy and founded the New Zealand Digital, in a post on eReport, explains the dilemma that now faces many publishers: 

Even where sales of EPUB ebooks lag behind Kindle sales, many publishers have now built their workflow around EPUB as their primary source files. These convert well into the current Kindle format, allowing publishers to maintain a single format. To keep this workflow, it will be important that Amazon supports error-free EPUB3 conversion in its Kindle Gen 2 toolset. But as complexity increases, so do the opportunities for things to break.

We won’t know until Amazon releases more details whether EPUB3 can continue to serve as this reference format. Indications are that EPUB3 is a richer format so publishers might want to restrict themselves to a feature subset that’s common to both platforms. No mention yet [in KF8], for instance, of JavaScript support, MathML, or EPUB3′s extensive accessibility features.



Amazon isn't the only major player to define its own format. Apple had already adopted an custom extension of the EPUB standard for illustrated books and magazines that worked only with its iBooks e-reader app.

Referring to the “browser wars” and the way in which  Microsoft in particular, introduced non-standard features in an effort to keep a competitive edge, Martin Taylor asks "Could we be in for the e-reader wars?"

If so many will find that is difficult to compete with Amazon when it comes to books, and to compete with Apple when it comes to devices.

More information:

EPUB 3 Becomes Final IDPF Specification

Related news:

Kindle Format 8 with HTML5 support


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Last Updated ( Monday, 31 October 2011 )