ISO/IEC TS 30135-1:2014
(Main)Information technology — Digital publishing — EPUB3 — Part 1: EPUB3 Overview
Information technology — Digital publishing — EPUB3 — Part 1: EPUB3 Overview
The EPUB® specification is a distribution and interchange format standard for digital publications and documents. EPUB defines a means of representing, packaging and encoding structured and semantically enhanced Web content — including HTML5, CSS, SVG, images, and other resources — for distribution in a single-file format. EPUB 3, the third major release of the standard, consists of a set of four specifications, each defining an important component of an overall EPUB Publication: -EPUB Publications 3.0 [Publications30], which defines publication-level semantics and overarching conformance requirements for EPUB Publications. -EPUB Content Documents 3.0 [ContentDocs30], which defines profiles of XHTML, SVG and CSS for use in the context of EPUB Publications. -EPUB Open Container Format (OCF) 3.0 [OCF3], which 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 [MediaOverlays30], which defines a format and a processing model for synchronization of text and audio. EPUB has been widely adopted as the format for digital books (eBooks), and these new specifications significantly increase the format's capabilities in order to better support a wider range of publication requirements, including complex layouts, rich media and interactivity, and global typography features. The expectation is that EPUB 3 will be utilized for a broad range of content, including books, magazines and educational, professional and scientific publications. This document provides a starting point for content authors and software developers wishing to understand these specifications. It consists of non-normative overview material, including a roadmap to the four building-block specification documents that compose EPUB 3. Another non-normative document, EPUB 3 Changes from EPUB 2.0.1 [EPUB3Changes], describes changes in EPUB 3 from the previous version, but is intended primarily for Authors and EPUB Reading System vendors migrating from EPUB 2.0.1 to EPUB 3 and for those who anticipate supporting both versions.
Technologies de l'information — Publications numériques — EPUB3 — Partie 1: Aperçu général de EPUB3
General Information
Standards Content (Sample)
TECHNICAL ISO/IEC
SPECIFICATION TS
30135-1
First edition
2014-11-15
Information technology — Digital
publishing — EPUB3 —
Part 1:
EPUB3 Overview
Technologies de l'information — Publications numériques — EPUB3 —
Partie 1: Aperçu général de EPUB3
Reference number
©
ISO/IEC 2014
© ISO/IEC 2014
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Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, the joint
technical committee may decide to publish an ISO/IEC Technical Specification (ISO/IEC TS), which
represents an agreement between the members of the joint technical committee and is accepted for
publication if it is approved by 2/3 of the members of the committee casting a vote.
An ISO/IEC TS is reviewed after three years in order to decide whether it will be confirmed for a further three
years, revised to become an International Standard, or withdrawn. If the ISO/IEC TS is confirmed, it is
reviewed again after a further three years, at which time it must either be transformed into an International
Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC TS 30135 series were prepared by Korean Agency for Technology and Standards (as KS X 6070
series) with International Digital Publishing Forum and were adopted, under a special “fast-track procedure”,
by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its approval by the
national bodies of ISO and IEC.
ISO/IEC TS 30135 consists of the following parts, under the general title Information technology — Document
description and processing languages — EPUB 3:
— Part 1: Overview
— Part 2: Publications
— Part 3: Content Documents
— Part 4: Open Container Format
— Part 5: Media Overlay
— Part 6: Canonical Fragment Identifier
— Part 7: Fixed-Layout Documents
EPUB 3 Overview
Recommended Specification 11 October 2011
THIS VERSION
http://www.idpf.org/epub/30/spec/epub30-overview-20111011.html
LATEST VERSION
http://www.idpf.org/epub/30/spec/epub30-overview.html
PREVIOUS VERSION
http://www.idpf.org/epub/30/spec/epub30-overview-20110908.html
A diff of changes from the previous draft is available at this link.
All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and
dissemination of this work with changes is prohibited except with the written permission of the International
Digital Publishing Forum (IDPF).
EPUB is a registered trademark of the International Digital Publishing Forum.
Editors
Garth Conboy, Google Inc.
Matt Garrish, Invited Expert
Markus Gylling, DAISY Consortium
William McCoy, International Digital Publishing Forum (IDPF)
MURATA Makoto, JEPA EPUB Study Group
Daniel Weck, DAISY Consortium
TAB LE O F CO NTENTS
1. Introduction
1.1. Overview
1.2. Roadmap
2. Features
2.1. Package Document
2.2. Navigation
2.2.1. Reading Order
2.2.2. Navigation Document
2.3. Linking
2.4. Metadata
2.5. Content Documents
2.6. Rendering and CSS
2.7. Multimedia
2.8. Fonts
2.9. Scripting
2.10. Text-to-speech
2.11. Container
3. Global Language Support
3.1. Metadata
3.2. Content Documents
3.3. CSS
3.4. Fonts
3.5. Text-to-speech
3.6. Container
4. Accessibility
4.1. Navigation
4.2. Semantic Markup
4.3. Dynamic Layouts
4.4. Aural Renditions and Media Overlays
4.5. Fallbacks
4.6. Scripting
A. Glossary
B. Acknowledgements and Contributors
B.1. EPUB 3.0
B.2. EPUB 2.0.1
B.3. EPUB 1.0
References
› 1 Introduction
› 1.1 Overview
The EPUB® specification is a distribution and interchange format standard for digital publications and
documents. EPUB defines a means of representing, packaging and encoding structured and
semantically enhanced Web content — including HTML5, CSS, SVG, images, and other resources — for
distribution in a single-file format.
EPUB 3, the third major release of the standard, consists of a set of four specifications, each defining an
important component of an overall EPUB Publication:
EPUB Publications 3.0 [Publications30], which defines publication-level semantics and
overarching conformance requirements for EPUB Publications.
EPUB Content Documents 3.0 [ContentDocs30], which defines profiles of XHTML, SVG and CSS
for use in the context of EPUB Publications.
EPUB Open Container Format (OCF) 3.0 [OCF3], which 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 [MediaOverlays30], which defines a format and a processing model for
synchronization of text and audio.
EPUB has been widely adopted as the format for digital books (eBooks), and these new specifications
significantly increase the format's capabilities in order to better support a wider range of publication
requirements, including complex layouts, rich media and interactivity, and global typography features.
The expectation is that EPUB 3 will be utilized for a broad range of content, including books, magazines
and educational, professional and scientific publications.
This document provides a starting point for content authors and software developers wishing to
understand these specifications. It consists of non-normative overview material, including a roadmap to
the four building-block specification documents that compose EPUB 3.
Another non-normative document, EPUB 3 Changes from EPUB 2.0.1 [EPUB3Changes], describes
changes in EPUB 3 from the previous version, but is intended primarily for Authors and EPUB Reading
System vendors migrating from EPUB 2.0.1 to EPUB 3 and for those who anticipate supporting both
versions.
› 1.2 Roadmap
This section provides an overview of the EPUB 3 specifications by explaining in brief the components of a
Publication. Links to additional information within this document and to the specifications are included.
An EPUB Publication, at its most basic level, is a bundled collection of resources that can be reliably
and predictably ingested by an EPUB Reading System in order to render its contents to a User. Some of
these resources facilitate the discovery and processing of the EPUB Publication, while others make up
the content of the source publication. The latter, EPUB Content Documents, are described in Content
Documents and are fully defined in [ContentDocs30].
A Publication's resources are typically bundled for distribution as a ZIP-based archive with the file
extension .epub. As conformant ZIP archives, Publications can be unzipped by many software programs,
simplifying both their production and consumption. The container format is introduced in Container and
defined in [OCF3].
The container format not only provides a means of determining that the zipped content represents an
EPUB Publication (the mimetype file), but also provides a universally-named directory of informative
resources (/META-INF). Key among these is the container.xml file, which directs Reading Systems to the
root file of the Publication, the Package Document.
The Package Document is itself a kind of information warehouse for the Publication, storing metadata
about the specific work contained in the Publication, providing an exhaustive list of resources and defining
a default reading order. The Package Document is introduced in Package Document and defined in
[Publications30].
The preceding components of an EPUB Publication are not new to EPUB 3, and will be familiar to
anyone who has worked with Publications before, although they have been changed and enhanced in this
version. A new core addition to EPUB 3, however, is the Media Overlay Document, which defines a
means of synchronizing text and audio playback. The Overlay Document is introduced in Multimedia and
defined in [MediaOverlays30].
The following example shows the resources a minimal "Hello World" Publication might contain:
mimetype
META-INF/container.xml
Content/HelloWorld.opf
Content/HelloWorld.xhtml
While conceptually simple, an EPUB Publication is more than just a collection of HTML pages and
dependent assets in a ZIP package as represented in this example. The following sections of this
document delve into more detail about the primary features and functionality that Publications provide to
enhance the reading experience.
› 2 Features
This section covers the major features of EPUB, including important components and topics that apply to
the process of authoring EPUB Publications as a whole.
2.1 Package Document
›
Every EPUB Publication includes a single Package Document, which specifies all the Publication's
constituent content documents and their required resources, defines a reading order for linear
consumption, and associates Publication-level metadata and navigation information.
The Package Document represents a significant improvement on a typical Web site. A Web site, for
example, embeds references to its resources within its content, which, while a simple and flexible means
of identifying resources, makes it difficult to enumerate all the resources required to render it. In addition,
there is no standard way for a Web site to define that a sequence of pages make up a larger publication,
which is precisely what EPUB's spine element does (i.e., it provides an external declarative means to
explicitly specify navigation through a collection of documents). Finally, the Package Document defines a
standard way to represent metadata globally applicable to a collection of pages.
The Package Document and other Publication-level constructs are specified in [Publications30].
› 2.2 Navigation
› 2.2.1 Reading O rder
A key concept of EPUB is that a Publication consists of multiple resources that may be completely
navigated and consumed by a person or program in some specific order.
Many publications have an obvious reading order, or logical progression through their content. A novel is
an example of a highly sequential document — it typically has a beginning, middle and end — but not all
publications are so ordered: a cookbook or collection of photographic images might be considered to be
more like a database. All documents do, however, have at least one logical ordering of all their top-level
content items, whether by date, topic, location or some other criteria (e.g., a cookbook is typically
ordered by type of recipe).
Every EPUB Publication defines at least one such logical ordering of all its top-level content (the spine
[Publications30]), as well as a declarative table of contents (the EPUB Navigation Document
[ContentDocs30]). Publications make these data structures available in a machine-readable way external
to the content, simplifying their discovery and use.
EPUB Publications are not limited to the linear ordering of their contents, nor do they preclude linking in
arbitrary ways — just like the Web, EPUB Publications are built on hypertext — but the basic
consumption and navigation can be reliably accomplished in a way that is not true for a set of HTML
pages.
› 2.2.2 Navigation Document
Every EPUB Publication contains a special XHTML Content Document called the EPUB Navigation
Document, which uses the HTML5 nav element to define human- and machine-readable navigation
information.
The Navigation Document supersedes the NCX document [OPS2], and the inclusion of NCX documents
is only recommended for forward compatibility in older Reading Systems. The Navigation Document,
while maintaining the baseline accessibility and navigation support and features of the NCX, introduces
new functionality and rendering features to enhance navigation for all Users. Prime among these are
better support for internationalization (as an XHTML5 document itself, the Navigation Document natively
supports ruby annotations) and support for embedded grammars (MathML and SVG can be included
within navigation links).
As XHTML Content Documents, Navigation Documents also provide a flexible means of tailoring the
navigation display using CSS and the hidden attribute [ContentDocs30] while not impacting access to
information for accessible Reading Systems.
The structure and semantics of Navigation Documents are defined in EPUB Navigation Documents
[ContentDocs30].
› 2.3 Linking
The new EPUB Canonical Fragment Identifier (epubcfi) Specification [EPUBCFI] defines a standardized
method for linking into a Publication.
Required support for this scheme in Reading Systems means that EPUB now has an interoperable
linking mechanism, one that can, for example, facilitate the sharing of bookmarks and reading locations
across devices.
› 2.4 Metadata
EPUB Publications provide a
...
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