EPUB 2 and EPUB 3
What is EPUB, .epub, OPS/OCF & OEB?
EPUB 2 is composed of three open standards, the Open Publication Structure (OPS), Open Packaging Format (OPF) and Open Container Format (OCF).
Open Packaging Format (OPF), identifies the files used in the .epub file
Open Publication Structure (OPS), contains the marked-up content
Open Container Format (OCF), collects all files as a ZIP archive
Please note: OPS is now called EPUB Content Documents and .epub is the file extension of an XML format for reflowable digital books and publications.
EPUB allows publishers to produce and send a single digital publication file through distribution and offers consumers interoperability between software/hardware for unencrypted reflowable digital books and other publications. The Open eBook Publication Structure or OEB, originally produced in 1999, is the precursor to OPS.
The International Digital Publishing Forum’s (IDPF) Open Publication Structure for e-books has incorporated DAISY XML into its EPUB standard as its preferred vocabulary. The EPUB standards however, initially were not developed primarily for people with print disabilities; they are a mainstream set of standards. Publishers in North America and Europe are increasingly adopting the EPUB standards.
EPUB 3 is aligned with HTML5, representing a major revision of the EPUB standard. The Recommended Specification is available at http://idpf.org/epub/30. The DAISY Consortium has played an integral part in the development of EPUB 3, ensuring that accessibility features are woven through its entire fabric. Some key features include enriched semantic structure, support for synthesized speech pronunciation, enhanced Global Language support, Math ML support and the navigation document that allows readers to quickly and efficiently move through the structure of the book. Support for synchronized audio and text is enabled through "Media Overlays" providing the reading experience already enjoyed by the many readers of DAISY Digital Talking Books around the world.
Text is available under the terms of the DAISY Consortium Intellectual Property Policy, Licensing, and Working Group Process.