Proposed Specification 28 February 2014
A diff of changes from the previous draft is available at this link.
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Table of Contents
spine element
dc:source element
dc:type element
collection element
EPUB® is an interchange and delivery format for digital publications, based on XML and Web Standards. An EPUB Publication can be thought of as a reliable packaging of Web content that represents a digital book, magazine, or other type of publication, and that can be distributed for online and offline consumption.
This document, EPUB 3.0.1 Changes from EPUB 3.0, describes changes made in the first minor revision of the EPUB 3.0 specifications, highlighting key changes and additions.
This document is non-normative. Consult the EPUB specification documents for definitive information on EPUB 3:
EPUB Publications 3.0.1 [Publications301], which defines publication-level semantics and overarching conformance requirements for EPUB Publications.
EPUB Content Documents 3.0.1 [ContentDocs301], which defines profiles of XHTML, SVG and CSS for use in the context of EPUB Publications.
EPUB Open Container Format (OCF) 3.0.1 [OCF301], which defines a file format and processing model for encapsulating a set of related resources into a single-file (ZIP) Container.
EPUB Media Overlays 3.0.1 [MediaOverlays301], which defines a format and a processing model for synchronization of text and audio.
Unless otherwise specified, terms used herein have the meaning defined in these specifications.
EPUB had its roots in the interchange format known as the Open EBook Publication Structure (OEBPS). OEBPS 1.0 was approved in 1999 by the Open eBook Forum, an organization that later became the International Digital Publishing Forum (IDPF). Subsequent revisions 1.1 and 1.2 were approved by the IDPF in 2001 and 2002 respectively.
It was realized that a need existed for a format standard that could be used for delivery as well as interchange, and work began in late 2005 on a single-file container format for OEPBS, which was approved by the IDPF as the OEBPS Container Format (OCF) in 2006. Work on a 2.0 revision of OEBPS began in parallel which was approved as the renamed EPUB 2.0 in October, 2007, consisting of a triumvirate of specifications: Open Package Format (OPF), Open Publication Format (OPF) together with OCF. EPUB 2.0.1, a maintenance update to the 2.0 specification set primarily intended clarify and correct errata in the specifications, was approved in September, 2010. [OPF2] [OPS2] [OCF2]
Work on a major new 3.0 revision of the EPUB specifications began in 2010, with the goal of aligning EPUB more closely with HTML5, and in the process bringing new, native multimedia features, sophisticated CSS layout rendering and font embedding, scripted interactivity, enhanced global language support, and improved accessibility. A new specification, EPUB Media Overlays was also introduced, enabling text and audio synchronization in EPUB Publications. To better align the specification names with the standard, the Open Package Format specification was renamed EPUB Publications and the Open Publication Format specification was renamed EPUB Content Documents. The EPUB 3.0 specifications were approved in October, 2011. [Publications30] [ContentDocs30] [OCF30] [MediaOverlays30]
spine elementAll Content Documents referenced from Content Documents in the
spine
[Publications301]
now themselves have to be listed in the in the spine.
dc:source elementThe restriction to only one dc:source element [Publications301] has been removed.
Identification of the print source for pagination is now done by refining the dc:source element with the new
source-of property
[Publications301]
.
dc:type elementThe restriction to only one dc:type element [Publications301] has been removed.
Refer to the EPUB Registry of Publication Types for the list of IDPF-recognized types that can be used with this element.
collection elementThe new collection element [Publications301] provides a framework for developing specialized behaviors and rendering in EPUB 3. It is not intended for use as defined in the Publications specification by Authors, but provides an extension point for functionality to be built on top of. It is being used by the EPUB Indexes specification, for example, to allow an index split across multiple XHTML Content Documents to be identified and rejoined (e.g., for machine processing and presentation).
The list of reserved prefixes that can be used in package metadata has been removed from the Publications specification to simplify adding prefixes outside of a specification revision. The list of prefixes can now be found in EPUB Publications Reserved Prefixes.
The prefix schema has been reserved for including schema.org metadata.
The meta element metadata properties have been expanded to allow the collection an EPUB Publication belongs to to be identified. The
belongs-to-collection property
[Publications301]
identifies the collection title and the
collection-type
[Publications301]
the nature of the collection (series and sets are predefined values).
The vocabulary of properties that can be used in the
link element
[Publications301]
rel attribute is now defined in the EPUB Link Relationships Vocabulary to allow adding new relationships between revisions.
A new generic record property has been added for the link element, allowing the referencing of any metadata record that can be identified by its media type.
Fixed-layout metadata that was formerly defined in EPUB 3 Fixed-Layout Documents has now been merged into the [Publications301] and [ContentDocs301] specifications. All of the fixed-layout metadata properties [Publications301] are now defined in Publications, and support for these properties is now required in Reading Systems.
The rendition:flow property [Publications301] was added to allow Authors to indicate the desired way in which to flow Content Documents (e.g., to create a continuous flow).
The rendition:align-x-center property [Publications301] was added to enable Authors to specify that Content Documents are to be centered horizontally. This property was added primarily to handle the problem of Naka-Tobira.
The list of reserved prefixes that can be used in epub:type attribute has been removed from the Content Documents specification to simplify adding prefixes outside of a specification revision. The list of prefixes can now be found in EPUB Content Documents Reserved Prefixes.
Both [RDFa11] and [Microdata] attributes are now valid for use in XHTML Content Documents. Vocabularies, such as defined at schema.org, can be used with these attributes to enrich content.
trigger elementThe following [XML Events] have been added to
the trigger element
[ContentDocs301]
to override default behaviors and prevent propagation of events: phase, defaultAction and propagate.
Custom attributes [ContentDocs301] are now allowed in XHTML Content Documents.
To improve interoperability, the IDPF is maintaining a registry of custom attributes.
(Note that custom attributes have always been allowed in SVG provided they meet the requirements outlined in that specification.)
aria-describedat attributeThe new [WAI-ARIA-1.1] aria-describedat attribute [ContentDocs301] has been added, allowing out-of-band descriptions to be added to any element. Descriptions referenced from this attribute can be located inside or outside the EPUB Container.
Two new modules have been added to the baseline profile:
The syntax and values of the CSS Writing Modes properties have changed. Refer to CSS Writing Modes [ContentDocs301] for more information.
The nature of the contents of an OCF Container has been clarified: an EPUB Publication is now defined as the single work represented in the Container, and is represented by one or more Renditions of its content (previously each Rendition was defined as an EPUB Publication, even though the Renditions could all be related).
It is no longer valid for Renditions of different EPUB Publications to be bundled together, although this was not encouraged previously.
The order of obfuscation and compression of resources has been clarified in Obfuscation Algorithm [OCF301] such that obfuscation is required to occur before compression. Reading System developers are advised to consider that the reverse order may be encountered due to the lack of clarity previously (see the note at the end of the section for more information).
The addition of the playback-active-class property allows Authors to control the appearance of text that is not currently being read. This property is applied to a Content Document's document element (e.g., the [HTML5]
html element). The property could be used to grey out all text when playback is active, for example, to better focus the User's attention on the text that is currently being read.
Updating the EPUB Structural Semantics Vocabulary has been unbound from the EPUB specifications revision cycle. The EPUB Working Group can now vet new property requests and make additions on an ongoing basis.
Many new additions were made to the vocabulary, most notably a new section dedicated to educational properties. Refer to the EPUB wiki for a complete list of changes.
This appendix is informative
EPUB has been developed by the International Digital Publishing Forum in a cooperative effort, bringing together publishers, vendors, software developers, and experts in the relevant standards.
The EPUB 3 specifications were prepared by the International Digital Publishing Forum’s EPUB Maintenance Working Group, operating under a charter approved by the membership in May, 2010 under the leadership of:
Active members of the working group included:
› IDPF Members
› Invited Experts/Observers
For more detailed acknowledgements and information about contributors to each version of EPUB, refer to Acknowledgements and Contributors [EPUB3Overview] .
[ContentDocs30] EPUB Content Documents 3.0 .
[ContentDocs301] EPUB Content Documents 3.0.1 .
[MediaOverlays30] EPUB Media Overlays 3.0 .
[MediaOverlays301] EPUB Media Overlays 3.0.1 .
[Microdata] HTML Microdata (20121025) . 25 October 2012.
[OCF2] Open Container Format 2.0.1 .
[OCF30] Open Container Format 3.0 .
[OCF301] Open Container Format 3.0.1 .
[OPF2] Open Packaging Format 2.0.1 .
[OPS2] Open Publication Structure 2.0.1 .
[Publications30] EPUB Publications 3.0 .
[Publications301] EPUB Publications 3.0.1 .
[RDFa11] RDFa Core 1.1 - Second Edition . Syntax and processing rules for embedding RDF through attributes. 22 August 2013.
[SVG] Scalable Vector Graphics (SVG) 1.1 (Second Edition) . 09 June 2011.
[WAI-ARIA-1.1] Accessible Rich Internet Applications (WAI-ARIA) 1.1 .
[XML Events] XML Events . 14 October 2003.
[EPUB3Overview] EPUB 3 Overview .