Open Standards

EDRLab actively participates in the maintenance of the EPUB 3 format, the creation of the W3C Audiobooks format (a profile of the W3C Web Publications format) and is incubating the innovative DiViNa format (for Digital Visual Narratives).

This section describes these publishing standards and offers links to detailed information.


EPUB, the industry standard for digital publications, is suitable for content authoring, interchange, and distribution of ebooks and long-form articles. EPUB 3 is based on open technologies used on the latest Open Web Platform.

The current version of the standard is EPUB 3.2. EDRLab has been a contributor of this specification and is actively promoting its use in Europe. This version is compatible with the original EPUB 3.0.1, meaning that every publication compliant with the original version is still compliant with EPUB 3.2. You can consider the new version as a better written specification of the same standard.

The EPUB 3.2 specification is found here.

A large list of EPUB resources can also be found on the legacy IDPF website.

More information about EPUB 3
Anatomy of an EPUB 3 file

W3C Audiobooks

Until 2020, there was no standard interchange format for audiobooks. For every audiobook publication, recording studios are creating audio files, insert basic metadata inside these files and send them to different e-distributors using custom formats, as requested by these distributors. As the number of publishers, distributors and booksellers is moving up quickly, the lack of standard is becoming a real burden.

The W3C Publishing Working Group decided in 2019 to create such a standard, based on the W3C Web Publication model previously studied by this group, and EDRLab took an active part in its specification.

W3C Audiobooks is now a W3C Recommendation and the W3C Publishing working group is expecting implementations and feedback on the standard.

Publishers can exchange audiobooks with distributors using the W3C Audiobooks format. Audiobook which are not protected by the LCP DRM can be distributed in this format also to end users, as a package or as an online stream.

The W3C Audiobooks format is transformed inside Readium toolkits into an internal model specified as the audiobook profile for the Readium Webpub Manifest, a format that we can call “Readium Audiobooks”. If a W3C Audiobook must be protected by the LCP DRM, the LCP encryption tools converts it into a Readium Audiobook, which still retains the original W3C Manifest and entry page (if any).

Readium is willing to support in its toolkits:

  • W3C audiobooks as LPF files, without DRM
  • W3C audiobooks as online streams
  • Readium audiobooks as packaged files, optionally protected by the LCP DRM
  • Readium audiobooks as online streams.

Thorium Reader (and therefore Readium Desktop) already supports all variants.

Divina – Digital Visual Narratives

Bande dessinée, Comics, Manga, Webtoons: these different variants of the same art (the 9th art in France), that we have decided to call Digital Visual Narratives (DiViNa), are experiencing different market growths: booming in Asia, strong in the US, nascent in Europe.

EDRLab created a working group in 2018, which goal is to create an open interchange format and develop authoring and reading solutions supporting this format, with partners representing the different stages of a publishing production and distribution workflow, i.e. authors, publishers, booksellers and national libraries involved in digital preservation.

The work has reached a first milestone in Q1 2020, with the release of two first “levels” of complexity.

The Divina format is presented in more details here.

The specifications of the DiViNa format are maintained here.


In English

The Updated EPUB Is a Brilliant Balancing Act (2023), by Bill Kasdorf, Publishers Weekly

In French

Les formats du livre audio (2020), Agence régionale du livre, Provence Alpes Côte d’Azur

Other projects


The Readium projects provide rock-solid, performant building blocks and applications for processing EPUB3 publications. EDRLab is participating to the Readium codebase maintenance and evolution.

Discover the Readium projects


Support for people with print disabilities is a key part of our mission. We collaborate with European publishers and major inclusive organizations on the creation of a born-accessible ebook market. We also make sure that Readium projects take into account the assistive technologies used by visually-impaired users.

Learn more about our accessibility efforts

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