Proposed Specification 8 September 2011
A diff of changes from the previous draft is available at this link.
Please refer to the errata for this document, which may include some normative corrections.
Copyright © 2010, 2011 International Digital Publishing Forum™
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.
Table of Contents
package Elementmetadata Elementidentifier Elementtitle Elementlanguage Elementmeta Elementmeta Element (OPF2) [OBSOLETE]link Elementmanifest Elementitem Elementspine Elementitemref Elementguide Element [DEPRECATED]bindings ElementmediaType Elementapplication/oebps-package+xml Media TypeThis section is informative
This specification, EPUB Publications 3.0, defines publication-level semantics and conformance requirements for EPUB® 3, including the format of the Package Document and rules for how this document and other Publication Resources are associated to create a conforming EPUB Publication.
This specification is one of a family of related specifications that compose EPUB 3, the third major revision of an interchange and delivery format for digital publications based on XML and Web Standards. It is meant to be read and understood in concert with the other specifications that make up EPUB 3:
The EPUB 3 Overview [EPUB3Overview], which provides an informative overview of EPUB and a roadmap to the rest of the EPUB 3 documents. The Overview should be read first.
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.
This specification supersedes Open Package Format 2.0.1 [OPF2]. Refer to [EPUB3Changes] for information on differences between this specification and its predecessor.
A logical document entity consisting of a set of interrelated resources and packaged in an EPUB Container, as defined by this specification and its sibling specifications.
A resource that contains content or instructions that contribute to the logic and rendering of the EPUB Publication. In the absence of this resource, the Publication might not render as intended by the Author. Examples of Publication Resources include the Package Document, EPUB Content Documents, EPUB Style Sheets, audio, video, images, embedded fonts and scripts.
With the exception of the Package Document itself, Publication Resources must be listed in the manifest and must be bundled in the EPUB container file unless specified otherwise in Publication Resource Locations.
Examples of resources that are not Publication Resources include those identified by the Package Document link element and those identified in outbound hyperlinks that resolve outside the EPUB Container (e.g., referenced from an [HTML5] a element href attribute).
A Publication Resource that is not a Core Media Type. A Foreign Resource requires at least one fallback, as defined in Restrictions and Fallbacks.
A Publication Resource that is a Core Media Type and may therefore be included in the EPUB Publication without the provision of fallbacks.
A Publication Resource that conforms to one of the EPUB Content Document definitions (XHTML or SVG).
An EPUB Content Document is a Core Media Type, and may therefore be included in the EPUB Publication without the provision of fallbacks.
An EPUB Content Document conforming to the profile of [HTML5] defined in XHTML Content Documents [ContentDocs30].
XHTML Content Documents use the XHTML syntax of [HTML5].
An EPUB Content Document conforming to the constraints expressed in SVG Content Documents [ContentDocs30].
A specialization of the XHTML Content Document, containing human- and machine-readable global navigation information, conforming to the constraints expressed in EPUB Navigation Documents [ContentDocs30].
An EPUB Content Document that includes scripting or an XHTML Content Document that contains HTML5 forms elements.
Refer to Scripted Content Documents [ContentDocs30] for more information.
An EPUB Content Document referenced directly from the spine
A set of Publication Resource types for which no fallback is required. Refer to Publication Resources for more information.
A Publication Resource carrying bibliographical and structural metadata about the EPUB Publication, as defined in Package Documents.
The digital (or physical) embodiment of a work of intellectual content. Changes to the content such as significant revision, abridgement, translation, or the realization of the content in a different digital or physical form result in a new manifestation. There may be many individual but identical copies of a manifestation, termed 'instances' or 'items'. The ISBN is an example of a manifestation identifier, and is shared by all instances of that manifestation.
All instances of a manifestation need not be bit-for-bit identical, as minor corrections or revisions are not judged to create a new manifestation or work.
The Unique Identifier is the primary identifier for an EPUB Publication, as identified by the unique-identifier attribute. The Unique Identifier may be shared by one or many Manifestations of the same work that conform to the EPUB standard and embody the same content, where the differences between the Manifestations are limited to those changes that take account of differences between EPUB Reading Systems (and which themselves may require changes in the ISBN).
The Unique Identifier is less granular than the ISBN. However, significant revision, abridgement, etc. of the content requires a new Unique Identifier.
The Package Identifier allows any instance of an EPUB Publication to be compared against another to determine if they are identical, different versions of the same Manifestation, or unrelated.
Refer to Package Identifier for more information.
A list of all Publication Resources that constitute the EPUB Publication.
Refer to manifest for more information.
An ordered list of Publication Resources, typically EPUB Content Documents, representing the default reading order of the Publication.
Refer to spine for more information.
An XML document that associates the XHTML Content Document with pre-recorded audio narration in order to provide a synchronized playback experience, as defined in [MediaOverlays30].
The rendering of the textual content of an EPUB Publication as artificial human speech using a synthesized voice.
A CSS Style Sheet conforming to the CSS profile defined in EPUB Style Sheets [ContentDocs30].
The region of an EPUB Reading System in which the content of an EPUB Publication is rendered visually to a User.
A Viewport capable of displaying CSS-styled content.
The ZIP-based packaging and distribution format for EPUB Publications defined in [OCF3].
The person(s) or organization responsible for the creation of an EPUB Publication, which is not necessarily the creator of the content and resources it contains.
An individual that consumes an EPUB Publication using an EPUB Reading System.
A system that processes EPUB Publications for presentation to a User in a manner conformant with this specification and its sibling specifications.
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
All sections of this specification are normative except where identified by the informative status label "This section is informative". The application of informative status to sections and appendices applies to all child content and subsections they may contain.
All examples in this specification are informative.
This section defines conformance requirements for EPUB Publications and EPUB Reading Systems at the Publication level. Conformance requirements particular to specific Publication Resources and processing contexts are located in the specifications referenced herein.
An EPUB Publication must meet all of the following criteria:
› All Publication Resources it contains must be represented in the Package Document (as defined in manifest), adhere to the constraints for Core Media Types and Fallback and be located as per Publication Resource Locations.
› It must contain exactly one Package Document, which must conform to the content requirements defined in Package Document — Content Conformance.
› It must contain at least one EPUB Content Document conformant to the content requirements defined in EPUB Content Documents [ContentDocs30].
› It may contain zero or more EPUB Style Sheets conformant to the content requirements defined in EPUB Style Sheets — Content Conformance [ContentDocs30].
› It may contain zero or more PLS Documents conformant to the content requirements defined in PLS Documents — Content Conformance [ContentDocs30].
› It may contain zero or more Media Overlay Documents conformant to the content requirements defined in [MediaOverlays30].
› It may contain zero or more Publication Resources in addition to those listed above, each of which must adhere to the requirements in All Publication Resources.
› It must be packaged in a EPUB Container as defined in [OCF3].
An EPUB Reading System must meet all of the following criteria:
› It must process the EPUB Container as defined in [OCF3].
› It must process the Package Document as defined in Package Document — Reading System Conformance, and honor all presentation logic expressed through the Package Document (e.g., the reading order, fallback chains and bindings).
› It must not fail catastrophically if it encounters two distinct EPUB Publications with the same Unique Identifier.
› Unless specified as conditional behavior in this section, it must support all Core Media Type Resources.
› It may support an arbitrary set of Foreign Resource types, and must process fallbacks for unsupported Foreign Resources as defined in Restrictions and Fallbacks if not.
› It must process XHTML Content Documents as defined in XHTML Content Documents — Reading System Conformance [ContentDocs30].
› It must process SVG Content Documents as defined in SVG Content Documents — Reading System Conformance [ContentDocs30].
› If it has a CSS Viewport, it must support visual rendering of XHTML Content Documents as defined in EPUB Style Sheets — Reading System Conformance [ContentDocs30].
› If it has the capability to render raster images, it must support the raster image Core Media Types.
› If it has the capability to render vector images, it must support the vector image Core Media Types.
› If it has the capability to render pre-recorded audio, it must support the MP3 audio Core Media Type, should support the MP4 audio Core Media Type and should support Media Overlays [MediaOverlays30].
› If it supports Text-to-Speech (TTS) rendering, it should support PLS Documents [ContentDocs30], the CSS3 Speech features of the EPUB CSS Profile [ContentDocs30] and SSML attributes [ContentDocs30] in XHTML Content Documents.
› It must support the EPUB Canonical Fragment Identifiers scheme [EPUBCFI] for linking, and may support additional linking schemes as defined in the EPUB Linking Scheme Registry.
It is recommended that Reading Systems support at least one of the [H.264] and [VP8] video codecs, but this is not a conformance requirement; a Reading System may support no video codecs at all. Content creators and Reading System developers should take into consideration factors such as breadth of adoption, video playback quality, and technology usage royalty requirements when making a choice to include or implement video in either (or potentially, both) formats.
› It should process EPUB version 2 Publications as defined in [OPF2], [OPS2] and [OCF2].
› It must attempt to process any Publication whose Package Document version attribute designates a version lower than 3.0 or which omits the version attribute.
› It should attempt to process any Publication whose Package Document version attribute designates a version higher than 3.0 or which omits the version attribute.
› It must be a conformant non-validating processor [XML].
› It must be a conformant processor as defined in [XMLNS].
› It must support xml-stylesheet processing instructions [ASSOCSS], and may support additional processing instructions.
› It must be a conformant application as defined by [XML Base].
A conforming Reading System is not necessarily a single dedicated program or device, but may exist as a distributed system.
This section is informative
The Package Document carries bibliographic and structural metadata about an EPUB Publication, and is thus the primary source of information about how to process and display it.
The Package Document is an XML document consisting of a set of container elements, each dedicated to housing information about a particular aspect of the Publication. These containers effectively centralize metadata for the Publication, detail the individual resources that compose it and provide reading order and other information for rendering the Publication to a User.
The following list summarizes the information a Package Document contains:
Publication metadata — mechanisms for including and/or referencing metadata applicable to the entire Publication and particular resources within it.
A Publication manifest — identifies (via IRI) and describes (via MIME media type) the set of resources that collectively compose the Publication.
A spine — an ordered sequence of ID references to top-level resources in the manifest from which all other resources in the set can be reached or utilized. The spine defines the default reading order of the Publication.
Fallback chains — an optional means for Publications to define an ordered list of top-level resources that can be considered content equivalents that a Reading System can choose between for rendering.
Bindings — an optional means of associating script-based implementations with custom media types.
A Package Document must meet all of the following criteria:
› It must meet the conformance constraints for XML documents defined in XML Conformance.
› It must be valid to the Package Document schema, as defined in Appendix A, Package Document Schema, and conform to all content conformance constraints expressed in Package Document Definition.
› The Package Document filename should use the file extension .opf.
Package Documents have the MIME media type application/oebps-package+xml [RFC4839].
An EPUB Reading System must meet all of the following criteria:
› It must process the Package Document in conformance with all Reading System conformance constraints expressed in Package Document Definition.
All elements [XML] defined in this section are in the http://www.idpf.org/2007/opf namespace [XMLNS] unless otherwise specified.
package ElementThe package element is the root container of the Package Document and encapsulates Publication metadata and resource information.
package
The package element is the root element of the Package Document.
version [required]Specifies the EPUB specification version to which the Publication conforms.
The attribute must have the value 3.0 to indicate compliance with this version of the specification.
unique-identifier [required]An IDREF [XML] that identifies the dc:identifier element that provides the package's preferred, or primary, identifier.
Refer to Publication Identifiers for more information.
prefix [optional]Declaration mechanism for prefixes not reserved by this specification.
Refer to The prefix Attribute for more information.
xml:lang [optional]Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].
dir [optional]Specifies the base text direction of the content and attribute values of the carrying element and its descendants.
Inherent directionality specified using [Unicode] takes precedence over this attribute.
Allowed values are ltr (left-to-right) or rtl (right-to-left).
id [optional]The ID [XML] of this element, which must be unique within the document scope.
In this order: metadata [required], manifest [required], spine [required], guide [optional/deprecated], bindings [optional]
metadata ElementThe metadata element encapsulates Publication meta information.
metadata
Required first child of package.
The metadata element has no attributes defined in this specification.
In any order: dc:identifier [1 or more], dc:title [1 or more], dc:language [1 or more], DCMES Optional Elements [0 or more], meta [1 or more], OPF2 meta [0 or more], link [0 or more]
The minimal required metadata that Publications must include consists of three elements from the Dublin Core Metadata Element Set [DCMES] — title, identifier and language — together with the modified property from DCMI Metadata Terms [DCTERMS]. Refer to the example at the end of this section for an instance of a complete minimal metadata set.
Additional optional metadata is expressed using the DCMES optional elements and the meta element.
Examples
The following example represents the minimal set of metadata that all Publications must contain.
<package … unique-identifier="pub-id">
…
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
<dc:title>Norwegian Wood</dc:title>
<dc:language>en</dc:language>
<meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
</metadata>
…
</package>
identifier ElementThe [DCMES] identifier element contains a single identifier associated with the EPUB Publication, such as a UUID, DOI, ISBN or ISSN.
dc:identifier
http://purl.org/dc/elements/1.1/
Required child of metadata. Repeatable.
id [optional] The ID [XML] of this element, which must be unique within the document scope.
The id attribute is required on the identifier element containing the unique identifier. See below.
Text
Every metadata section must include at least one identifier element containing an unambiguous identifier for the Publication. Multiple identifier elements are permitted, but only one can be marked as the Unique Identifier via the package element unique-identifier attribute.
The following example shows the unique identifier element for a Publication.
<package … unique-identifier="pub-id">
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
…
</metadata>
</package>This specification makes a distinction between the Unique Identifier for an EPUB Publication and the identifier that uniquely identifies a specific version of it (i.e., to be able to differentiate EPUB Publications containing different versions of the same Manifestation). Two copies of an EPUB that are bit-for-bit identical are the same version and must retain the same last modified date. If they are not bit-for-bit identical, they represent different versions, and must have different last modified dates.
To identify a specific version of a packaged Publication, a Package Identifier can be constructed by combining the Unique Identifier with the last modified date of the Publication. Changes between versions may include minor typographic or markup corrections, without affecting the Unique Identifier. Significant revisions to the content that result in a new edition require a change of the Unique Identifier. For more information on the semantics and requirements of the Package Identifier, refer to Package Identifier.
This specification imposes no additional restrictions or requirements on identifiers except that they must be at least one character in length. It is strongly recommended that all identifiers be fully qualified URIs, however.
Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.
To determine whether an identifier conforms to an established system or has been granted by an issuing authority, Reading Systems should parse the value of the property. For additional precision (e.g., if the scheme cannot be determined from the value or could lead to an ambiguous result), Authors may attach an identifier-type property to assist in Reading System identification. When included, the identifier-type property should take precedence over value parsing the identifier.
The following example shows how an identifier can be additionally marked as a DOI using the identifier-type property.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:identifier id="pub-id">urn:doi:10.1016/j.iheduc.2008.03.001</dc:identifier>
<meta refines="#pub-id" property="identifier-type" scheme="onix:codelist5">06</meta>
…
</metadata>
This specification does not require or endorse the use of any specific scheme for identifiers, and imposes no restrictions or requirements on identifier-type identifiers beyond those specified in the property definition.
When an EPUB Publication is derived from another publication, the identifier for that source publication may be included in the Publication metadata, and must be represented using the DCMES source element.
title ElementThe [DCMES] title element represents an instance of a name given to the EPUB Publication.
dc:title
http://purl.org/dc/elements/1.1/
Required child of metadata. Repeatable.
id [optional]The ID [XML] of this element, which must be unique within the document scope.
xml:lang [optional]Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].
dir [optional]Specifies the base text direction of the content and attribute values of the carrying element and its descendants.
Inherent directionality specified using [Unicode] takes precedence over this attribute.
Allowed values are ltr (left-to-right) or rtl (right-to-left).
Text
Every metadata section must include at least one title element containing the title for the Publication. Multiple title elements are permitted, but the title-type property should be attached to indicate the type of title (e.g., the main title of a work, a subtitle, etc.).
The following example shows how to indicate different title types.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:title id="t1">A Dictionary of Modern English Usage</dc:title>
<meta refines="#t1" property="title-type">main</meta>
<dc:title id="t2">First Edition</dc:title>
<meta refines="#t2" property="title-type">edition</meta>
<dc:title id="t3">Fowler's</dc:title>
<meta refines="#t3" property="title-type">short</meta>
…
</metadata>
When adding the title-type property, Authors should designate only one title element as containing the main title for the Publication. If no means of determining title types is provided, or understood, Reading Systems must treat the first title element in document order as the main title. This specification does not define how additional title elements should be processed in such situations.
The optional display-seq property may also be attached to each title to indicate their primacy for display and other rendering purposes.
The following example shows how to indicate display sequence.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:title id="t1">The Red and the Black</dc:title>
<meta refines="#t1" property="title-type">main</meta>
<meta refines="#t1" property="display-seq">1</meta>
<dc:title id="t2">A Chronicle of the Nineteenth Century</dc:title>
<meta refines="#t2" property="title-type">subtitle</meta>
<meta refines="#t2" property="display-seq">2</meta>
<dc:title id="t3">A Chronicle of 1830</dc:title>
<meta refines="#t3" property="title-type">subtitle</meta>
<meta refines="#t3" property="display-seq">3</meta>
…
</metadata>
This specification imposes no additional restrictions or requirements on titles except that they must be at least one character in length.
Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.
Examples
The following example shows how the title "THE LORD OF THE RINGS, Part One: The Fellowship of the Ring" could be classified.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:title id="t1">The Fellowship of the Ring</dc:title>
<meta refines="#t1" property="title-type">main</meta>
<dc:title id="t2">The Lord of the Rings</dc:title>
<meta refines="#t2" property="title-type">collection</meta>
<meta refines="#t2" property="group-position">1</meta>
<dc:title id="t3">THE LORD OF THE RINGS, Part One: The Fellowship of the Ring</dc:title>
<meta refines="#t3" property="title-type">extended</meta>
…
</metadata>
The following example shows how the complex title "The Great Cookbooks of the World: Mon premier guide de cuisson, un Mémoire. The New French Cuisine Masters, Volume Two. Special Anniversary Edition" could be classified.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:title id="t1" xml:lang="fr">Mon premier guide de cuisson, un Mémoire</dc:title>
<meta refines="#t1" property="title-type">main</meta>
<meta refines="#t1" property="display-seq">2</meta>
<dc:title id="t2">The Great Cookbooks of the World</dc:title>
<meta refines="#t2" property="title-type">collection</meta>
<meta refines="#t2" property="display-seq">1</meta>
<dc:title id="t3">The New French Cuisine Masters</dc:title>
<meta refines="#t3" property="title-type">collection</meta>
<meta refines="#t3" property="group-position">2</meta>
<meta refines="#t3" property="display-seq">3</meta>
<dc:title id="t4">Special Anniversary Edition</dc:title>
<meta refines="#t4" property="title-type">edition</meta>
<meta refines="#t4" property="display-seq">4</meta>
<dc:title id="t5">The Great Cookbooks of the World:
Mon premier guide de cuisson, un Mémoire.
The New French Cuisine Masters, Volume Two.
Special Anniversary Edition</dc:title>
<meta refines="#t5" property="title-type">extended</meta>
…
</metadata>
language ElementThe [DCMES] language element specifies the language of the Publication content.
Every metadata section must include at least one language element with a value conforming to [RFC5646].
The following example shows a Publication is in U.S. English.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:language>en-US</dc:language>
…
</metadata>
Additional language elements may be included for multilingual Publications, but each element's value must conform to [RFC5646].
Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.
All elements from the [DCMES] element set — except for identifier, language and title, as defined above — are designated as optional. These elements all conform to the following generalized definition:
contributor | coverage | creator | date | description | format | publisher | relation | rights | source | subject | type
http://purl.org/dc/elements/1.1/
Optional child of metadata. Repeatable.
id [optional]The ID [XML] of this element, which must be unique within the document scope.
xml:lang* [optional] Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].
dir* [optional]Specifies the base text direction of the content and attribute values of the carrying element and its descendants.
Inherent directionality specified using [Unicode] takes precedence over this attribute.
Allowed values are ltr (left-to-right) or rtl (right-to-left).
Text
* The xml:lang and dir attributes are permitted only on the following elements: contributor, coverage, creator, description, publisher, relation, rights and subject.
The value of all optional [DCMES] elements must be at least one character in length.
Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.
Except as detailed below, this specification does not modify the [DCMES] definitions for these elements.
The DCMES contributor Element
The contributor element is used to represent the name of a person, organization, etc. that played a secondary role in the creation of the content of a Publication.
The use of the contributor element is identical to the use of the creator element in all other respects, as detailed in the next section.
The DCMES creator Element
The creator element represents the name of a person, organization, etc. responsible for the creation of the content of a Publication. The role property can be attached to the element to indicate the function the creator played in the creation of the content.
The following example shows how to represent a creator as an author using a MARC relators term.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:creator id="creator">Haruki Murakami</dc:creator>
<meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
…
</metadata>
The creator element should contain the name of the creator as a Reading System will present it to a User. The file-as property may be attached to include a normalized form of the name, and the alternate-script property can be used to represent a creator's name in another language or script.
The following example shows the different ways a creator's name can be included to facilitate processing and rendering.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:creator id="creator">Haruki Murakami</dc:creator>
<meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
<meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta>
<meta refines="#creator" property="file-as">Murakami, Haruki</meta>
…
</metadata>
If a Publication has more than one creator, each should be included in a separate creator element. The order in which to render the creator names should be specified using the display-seq property.
The following example shows how to indicate the display order for creator elements.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:creator id="creator01">Lewis Carroll</dc:creator>
<meta refines="#creator01" property="role" scheme="marc:relators">aut</meta>
<meta refines="#creator01" property="display-seq">1</meta>
<dc:creator id="creator02">John Tenniel</dc:creator>
<meta refines="#creator02" property="role" scheme="marc:relators">ill</meta>
<meta refines="#creator02" property="display-seq">2</meta>
…
</metadata>
If no means of establishing the primacy of creators is included, Reading Systems must use the order of creator elements.
Secondary contributors should be represented using DCMES contributor elements.
The DCMES date Element
The date element must only be used to define the publication date of the EPUB Publication. The publication date is not the same as the last modified date (the last time the content was changed), which must be included using the [DCTERMS] modified property.
For compliance with EPUB 2 Reading Systems, the date string should conform to Date and Time Formats.
The following example shows a publication date.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:date>2000-01-01T00:00:00Z</dc:date>
…
</metadata>
Additional dates should be expressed using the specialized date properties available in the [DCTERMS] vocabulary, or similar.
The publication date may be common to all instances of a Publication or may change from instance to instance (if the Publication gets generated on demand, for example).
Only one date element is allowed.
The DCMES source Element
The source element must only be used to specify the identifier of the source publication from which this EPUB Publication is derived.
The following example shows the ISBN identifier for a Publication together with the source ISBN identifier for the print work it was derived from.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>
<meta refines="#isbn-id" property="identifier-type" scheme="onix:codelist5">15</meta>
<dc:source id="src-id">urn:isbn:9780375704024</dc:source>
<meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta>
…
</metadata>
The source element allows the print source of the pagination of a Publication to be determined.
Only one source element is allowed.
The DCMES type Element
The type element is used to indicate that the given Publication is of a specialized type (e.g., annotations packaged in EPUB format or a dictionary).
This specification does not define values for this element, however. The development of specialized Publication types, and the assignment of formal identifiers to represent them, will occur independently of this specification.
Only one type element is allowed.
meta ElementThe meta element provides a generic means of including package metadata, allowing the expression of primary metadata about the package or content and refinement of that metadata.
meta
As child of the metadata element. Repeatable.
property [required] A property.
Refer to Vocabulary Association Mechanisms for more information.
refines [context dependent] Identifies the expression or resource augmented by this element. The value of the attribute must be a relative IRI [RFC3987] pointing to the resource or element it describes.
The refines attribute is optional depending on the type of metadata being expressed. When omitted, the meta element defines a primary expression.
id [optional] The ID [XML] of this element, which must be unique within the document scope.
scheme [optional] A property data type value indicating the source the value of the element is drawn from.
Text
Each meta element defines a metadata expression, where the property attribute defines the statement being made in the expression and the text content of the element represents the assertion.
This specification defines two types of metadata expressions that can be defined using the meta element:
A primary expression is one in which the expression defined in the meta element establishes some aspect of the EPUB Publication. A meta element that omits a refines attribute defines a primary expression.
A subexpression is one in which the expression defined in the meta element enhances the meaning of the expression or resource referenced in its refines attribute. A subexpression may refine a media clip, for example, by expressing its duration, or refine a creator or contributor expression by defining the person's role.
Subexpressions are not limited to refining only primary expressions and resources; they may be used to refine the meaning of other subexpressions, thereby creating chains of information.
All of the [DCMES] elements represent primary expressions, and permit refinement by meta element subexpressions.
This specification reserves a set of vocabularies for use in the property attribute, but terms from any vocabulary may be used so long as a prefix is declared for the vocabulary.
The scheme attribute can be used to identify the system or scheme that a meta element's value is drawn from. The value of the scheme attribute is a property data type that resolves to the resource that defines the scheme.
The following example shows how a subexpression can be attached to an creator to indicate it represents an author. The scheme indicates the value is drawn from the MARC relators terms.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:creator id="creator">Haruki Murakami</dc:creator>
<meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
…
</metadata>
If a Reading System does not recognize the scheme attribute value, it should treat the value of the element as a string.
Reading Systems should ignore all meta elements whose property attributes define expressions they do not recognize. A Reading System must not fail when encountering unknown expressions.
In order to ensure that a Package Identifier can be constructed, the metadata element must contain exactly one meta element defining a [DCTERMS] modified property for the Publication. Additional modified properties may be included, but they must have a different subject (i.e., they must include a refines attribute pointing to an element or resource).
Every meta element must express a value that is at least one character in length after whitespace normalization.
Unless an individual property explicitly defines a different whitespace normalization algorithm, Reading Systems must trim all leading and trailing whitespace from the meta element values, as defined by the XML specification [XML], before further processing them.
Examples
The following example represents a more complete set of metadata that typical Publications will contain.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
…
<dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
<meta refines="#pub-id" property="identifier-type" scheme="xsd:string">uuid</meta>
<dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>
<meta refines="#isbn-id" property="identifier-type" scheme="onix:codelist5">15</meta>
<dc:source id="src-id">urn:isbn:9780375704024</dc:source>
<meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta>
<dc:title id="title">Norwegian Wood</dc:title>
<meta refines="#title" property="title-type">main</meta>
<dc:language>en</dc:language>
<dc:creator id="creator">Haruki Murakami</dc:creator>
<meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
<meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta>
<meta refines="#creator" property="file-as">Murakami, Haruki</meta>
<meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
</metadata>
The following example shows an identifier that has been issued by a metadata authority.
<package version="3.0"
unique-identifier="pub-id"
xmlns="http://www.idpf.org/2007/opf">
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:identifier id="pub-id">urn:uuid:1234-5678</dc:identifier>
<dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>
<meta refines="#isbn-id" property="meta-auth" id="meta-authority-01">Metadata Authority Inc.</meta>
<link refines="#meta-authority-01" rel="xml-signature" href="../META-INF/Signatures.xml#MAI-Signature"/>
…
</metadata>
</package>
<!-- in Signatures.xml -->
<signatures>
<Signature Id="MAI-Signature" xmlns="http://www.w3.org/2000/09/xmldsig#">
…
</Signature>
</signatures>
meta Element (OPF2) [OBSOLETE]The meta element defined in [OPF2] has been obsoleted and replaced by the new meta element, but may be included as an optional repeatable child of the metadata element for forwards compatibility purposes.
EPUB 3 Reading Systems must ignore this element.
link ElementThe link element is used to associate resources with a Publication, such as metadata records.
link
As a child of metadata. Repeatable.
href [required] An absolute or relative IRI reference [RFC3987] to a resource.
rel [required] A space-separated list of property values.
id [optional] The ID [XML] of this element, which must be unique within the document scope.
refines [optional] Identifies the expression or resource augmented by this element. The value of the attribute must be a relative IRI [RFC3987] pointing to the resource or element it describes.
When the refines attribute is omitted, the expression applies to the EPUB Publication as a whole.
media-type [optional] A media type [RFC2046] that specifies the type and format of the resource referenced by this link.
Empty
The metadata element may contain zero or more link elements.
The href attribute of the link element identifies the location of the resource — inclusion of which is optional in the container file — and the rel attribute defines the nature of the resource (i.e., its relation to the Publication or property specified in the refines attribute). Reading Systems are not required to dereference these resources. Refer to Metadata link Properties for the list of resource types that are recognized by this specification.
Resources identified by the link element href attribute must not be represented as items in the manifest.
When the link element references a metadata record, precedence must be given to metadata defined inline in the Package Document metadata element in the case of conflicts.
The optional refines attribute can be attached when the referenced resource applies to another metadata item (e.g., to tie an XML Signature [XML DSIG Core] to a metadata authority). The resource applies to the Publication as a whole when the attribute is not present.
If a Reading System does not recognize the relationship of the resource as defined in the rel attribute, it should ignore the link element.
Examples
The following example shows the link element used to associate three metadata resources with the Publication: an ONIX record, an XMP record, and a link to an informational web page. Note that as foaf is not a predefined prefix, the metadata extensibility mechanism is employed to associate the vocabulary.
<package … prefix="foaf: http://xmlns.com/foaf/spec/">
<metadata>
…
<link rel="onix-record" href="http://example.org/onix/12389347"/>
<link rel="xmp-record" href="http://example.org/xmp/12389347"/>
<link rel="foaf:homepage" href="http://example.org/book-info/12389347" />
…
</metadata>
…
</package>
manifest ElementThe manifest element provides an exhaustive list of the Publication Resources that constitute the EPUB Publication, each represented by an item element.
This specification supports internationalized resource naming, so elements and attributes that reference Publication Resources accept IRIs as their value. For compatibility with older Reading Systems that only accept URIs, resource names should be restricted to the ASCII character set.
item ElementThe item element represents a Publication Resource.
item
As a child of manifest. Repeatable.
id [required]The ID [XML] of this element, which must be unique within the document scope.
href [required]An IRI [RFC3987] specifying the location of the Publication Resource described by this item.
media-type [required]A media type [RFC2046] that specifies the type and format of the Publication Resource described by this item.
fallback [conditionally required]An IDREF [XML] that identifies the fallback for a non-Core Media Type.
Refer to Manifest Fallbacks for more information.
properties [optional]A space-separated list of property values.
Refer to Manifest item Properties for a set of properties defined by this specification.
media-overlay [optional]An IDREF [XML] that identifies the Media Overlay Document for the resource described by this item.
Refer to Packaging [MediaOverlays30] for more information.
Empty
Each item element in the manifest identifies a Publication Resource by the IRI provided in its href attribute. The IRI may be absolute or relative. In the case of relative IRIs, Reading Systems must use the IRI of the Package Document as the base when resolving these to absolute IRIs. The resulting absolute IRI must be unique within the manifest scope.
All Publication Resources must be referenced from the manifest, regardless of whether they are included in the EPUB Container or made available remotely. Refer to Publication Resource Locations for media type-specific requirements regarding resource locations.
The Publication Resource identified by an item element must conform to the applicable specification(s) as inferred from the MIME media type provided in the media-type attribute. Core Media Type Resources must use the media type designated in EPUB Core Media Types.
All Foreign Resources must provide a fallback as defined in Restrictions and Fallbacks.
All Publication Resources must declare any applicable descriptive metadata properties as defined in Manifest item Properties via the item element properties attribute. Exactly one item must be declared as the EPUB Navigation Document using the nav property.
Reading Systems must ignore all descriptive metadata properties that they do not recognize.
The manifest is not self-referencing: it must not include an item element that refers to the Package Document itself.
The order of item elements in the manifest is not significant. The presentation sequence of content documents is provided in the spine.
Examples
The following example shows a manifest that only contains Core Media Type Resources.
<manifest>
<item id="nav"
href="nav.xhtml"
properties="nav"
media-type="application/xhtml+xml"/>
<item id="intro"
href="intro.xhtml"
media-type="application/xhtml+xml"/>
<item id="c1"
href="chap1.xhtml"
media-type="application/xhtml+xml"/>
<item id="c1-answerkey"
href="chap1-answerkey.xhtml"
media-type="application/xhtml+xml"/>
<item id="c2"
href="chap2.xhtml"
media-type="application/xhtml+xml"/>
<item id="c2-answerkey"
href="chap2-answerkey.xhtml"
media-type="application/xhtml+xml"/>
<item id="c3"
href="chap3.xhtml"
media-type="application/xhtml+xml"/>
<item id="c3-answerkey"
href="chap3-answerkey.xhtml"
media-type="application/xhtml+xml"/>
<item id="notes"
href="notes.xhtml"
media-type="application/xhtml+xml"/>
<item id="cover"
href="./images/cover.svg"
properties="cover-image"
media-type="image/svg+xml"/>
<item id="f1"
href="./images/fig1.jpg"
media-type="image/jpeg"/>
<item id="f2"
href="./images/fig2.jpg"
media-type="image/jpeg"/>
<item id="css"
href="./style/book.css"
media-type="text/css"/>
<item id="pls"
href="./speech/dict.pls"
media-type="application/pls+xml"/>
</manifest>
The following example shows a manifest that references two Foreign Resources, and therefore uses the fallback chain mechanism to supply content alternatives. The fallback chain terminates with a Core Media Type.
<manifest>
<item id="item1"
href="chap1_docbook.xml"
media-type="application/docbook+xml"
fallback="fall1"/>
<item id="fall1"
href="chap1.xml"
media-type="application/z3986-auth+xml"
fallback="fall2" />
<item id="fall2"
href="chap1.xhtml"
media-type="application/xhtml+xml"/>
…
</manifest>
Refer also to the Manifest item properties examples for use of the properties attribute.
spine ElementThe spine element defines the default reading order of the EPUB Publication content by defining an ordered list of manifest item references.
spine
id [optional]The ID [XML] of this element, which must be unique within the document scope.
toc [optional]An IDREF [XML] that identifies the manifest item that represents the superseded NCX.
Refer to NCX Superseded for more information.
page-progression-direction [optional]The global direction in which the Publication content flows.
Allowed values are ltr (left-to-right), rtl (right-to-left) and default.
When the default value is specified, the Author is expressing no preference and the Reading System may chose the rendering direction. This value must be assumed when the attribute is not specified.
Multiple itemref elements [required]
The spine represents an ordered subset of the Publication Resources listed in the manifest, with content items not being referenced being ancillary to those that do.
Reading Systems must provide a means of rendering a Publication in the order defined by the spine, which includes: 1) recognizing the first primary (linear='yes') item in the spine as the beginning of the main reading order of the Publication; and, 2) rendering successive primary items in the order given in the spine.
Although the page-progression-direction attribute sets the global flow direction for a Publication, individual Content Documents and parts of Content Documents may override this setting (e.g., via the direction and writing-mode CSS properties). Reading Systems may also provide mechanisms to override the default direction (e.g., buttons or settings that allow the application of alternate style sheets).
NCX Superseded
The NCX feature defined in [OPF2] is superseded by the EPUB Navigation Document [ContentDocs30]. EPUB 3 Publications may include an NCX (as defined in OPF 2.0.1) for EPUB 2 Reading System forwards compatibility purposes, but EPUB 3 Reading Systems must ignore the NCX in favor of the EPUB Navigation Document.
itemref ElementThe child itemref elements of the spine represent a sequential list of Publication Resources (typically EPUB Content Documents). The order of the itemref elements defines the default reading order of the Publication.
itemref
As a child of spine. Repeatable.
idref [required]linear [optional]Specifies whether the referenced content is primary.
The value of the attribute must be yes or no. The default value is yes.
id [optional]The ID [XML] of this element, which must be unique within the document scope.
properties [optional]A space-separated list of property values.
Refer to Spine itemref Properties for a set of properties defined by this specification.
Empty
Each itemref element must reference an item in the manifest via its idref attribute.
Each referenced manifest item must be either a) an EPUB Content Document or b) another type of Publication Resource which, regardless of whether it is a Core Media Type Resource or a Foreign Resource, must include an EPUB Content Document in its fallback chain.
Although the EPUB Navigation Document is required in EPUB Publications, it is optional to include it in the spine.
The itemref element linear attribute indicates whether referenced item is considered primary (yes) or auxiliary (no) in the spine. This attribute may be used to enable Reading Systems to distinguish presentation of body content from supplementary content which might be, for example, presented in a popup window or omitted from an aural rendition.
Any applicable descriptive metadata properties, such as those defined in the Spine itemref Properties, should be declared via the properties attribute.
Reading Systems must ignore all metadata properties expressed in the properties attribute that they do not recognize.
Examples
The following example shows a spine element corresponding to the manifest example above.
<spine page-progression-direction="ltr">
<itemref idref="intro"/>
<itemref idref="c1"/>
<itemref idref="c1-answerkey" linear="no"/>
<itemref idref="c2"/>
<itemref idref="c2-answerkey" linear="no"/>
<itemref idref="c3"/>
<itemref idref="c3-answerkey" linear="no"/>
<itemref idref="notes" linear="no"/>
</spine>
guide Element [DEPRECATED]The guide element [OPF2] is deprecated in favor of the landmarks feature in the EPUB Navigation Document. Refer to The landmarks nav Element [ContentDocs30] for more information.
Authors may include the guide element in the Package Document for EPUB 2 Reading System forwards compatibility purposes. EPUB 3 Reading Systems must ignore the guide element when provided in EPUB 3 Publications whose EPUB Navigation Document includes the landmarks feature.
bindings ElementThe bindings element defines a set of custom handlers for media types not supported by this specification.
The package element may contain at most one bindings element.
The bindings element provides a means for Authors to include more sophisticated fallbacks than would otherwise be possible with the [HTML5] object element's intrinsic fallback mechanisms. When present, Reading Systems that support scripting must utilize the bindings element to handle object elements that reference unsupported media types.
Each of the bindings element's child mediaType elements defines a unique handler for one of the foreign media types referenced in the Publication's XHTML Content Documents.
When an unsupported media type is encountered during processing of a document, the Reading System must look up the handler in the bindings element by checking the media-type attribute of each mediaType element for a match (and before attempting any other type of fallback processing). If a match is found, the XHTML Content Document referenced in the element's handler attribute must be instantiated instead of the referenced resource. If no match is found, the Reading System should continue with normal fallback processing (i.e., check for an intrinsic fallback for the object).
The Reading System must instantiate the designated handler as if it had been referenced from the object element's data attribute with the following parameters:
srcthe value of which must be an IRI [RFC3987] to the resource (i.e., the value of the object element's data attribute).
typethe value of which must be the resource media type (i.e., the value of the object element's media-type attribute).
Any additional param children of the object element must be similarly added as parameters using the param's name attribute as the new parameter name and its value attribute as the new value.
For example, the following object element containing a foreign media type:
<object data="horse.ogg" media-type="audio/ogg"/>
<param name="autoplay" value="false">
</object>
would result in the following query string being sent to the handler XHTML Content Document after processing:
src=horse.ogg&type=audio/ogg&autoplay=false
All IRI reserved characters, plus the characters <, >, ", space, {, }, |, \, ^ and `, in the generated query string must be encoded and decoded as per [RFC3987].
object elements that reference media types handled by the bindings element are only processed in spine-referenced XHTML Content Documents (i.e., they are ignored in container-constrained scripting contexts).
Example
The following partial example illustrates how bindings can be used to provide a slideshow.
Consider a Publication with the following Package Document:
<package …>
…
<manifest>
<item id="pict1"
href="images/Pict1.jpg"
media-type="image/jpeg"/>
…
<item id="content"
href="content.xhtml"
media-type="application/xhtml+xml"/>
<item id="impl"
href="impl.xhtml"
media-type="application/xhtml+xml"
properties="scripted"/>
<item id="slideshow"
href="slideshow.xml"
media-type="application/x-demo-slideshow"/>
</manifest>
<bindings>
<mediaType handler="impl"
media-type="application/x-demo-slideshow"/>
</bindings>
…
</package>
and the following content in the file content.xhtml:
<html …>
…
<body>
…
<object data="slideshow.xml"
type="application/x-demo-slideshow">
<img src="images/Pict1.jpg"/>
<img src="images/Pict2.jpg"/>
<img src="images/Pict3.jpg"/>
<img src="images/Pict4.jpg"/>
</object>
…
</body>
</html>
and the following content in the file slideshow.xml:
<slides>
<slide src="images/Pict1.jpg" dur="3"/>
<slide src="images/Pict2.jpg" dur="3"/>
<slide src="images/Pict3.jpg" dur="3"/>
<slide src="images/Pict4.jpg" dur="3"/>
</slides>
Depending on the capabilities of the User's Reading System, they will see one of the following renditions of the slideshow:
If the Reading System supports the native slideshow format, it will render a rotating set of images as specified in slideshow.xml.
If the Reading System cannot support the slideshow media type but supports scripting, it can check the bindings element in the Package Document for a scripted fallback. There it will find a reference to the item element containing the handler document (impl.xhtml). The Reading System can now load this document to render a JavaScripted equivalent of the slideshow (source not shown).
If the Reading System does not support the slideshow media type and also does not support scripting, it will use the fallback images specified in the object element to show a static set of all the images.
mediaType ElementThe mediaType element associates a Foreign Resource media type with a handler XHTML Content Document.
mediaType
As a child of bindings. Repeatable.
Empty
Each child mediaType of a bindings element must define a unique content type in its media-type attribute, and the media type specified must not be a Core Media Type.
The required handler attribute must reference the ID [XML] of an item in the manifest of the default implementation for this media type. The referenced item must be an XHTML Content Document.
All XHTML Content Documents designated as handlers must have the scripted property set in their manifest item's properties attribute.
The Package Document's author is responsible for including a primary identifier that is unique to one and only one particular EPUB Publication. This Unique Identifier, whether chosen or assigned, must be stored in a dc:identifier element in the Package metadata and be referenced as the Unique Identifier in the package element unique-identifier attribute.
Although not static, changes to the Unique Identifier for a Publication should be made as infrequently as possible. New identifiers should not be issued when updating metadata, fixing errata or making other minor changes to the Publication.
The Unique Identifier of an EPUB Publication typically should not change with each minor revision to the package or its contents, as Unique Identifiers are intended to have maximal persistence both for referencing and distribution purposes. Each release of a Publication normally requires that the new version be uniquely identifiable, however, which results in the contradictory need for reliable Unique Identifiers that are changeable.
To redress this problem of identifying minor modifications and releases without changing the Unique Identifier, this specification defines the semantics for a Package Identifier, or means of distinguishing and sequentially ordering Publications with the same Unique Identifier. The Package Identifier is not an actual property in the package metadata section, but is a value that can be obtained from two required pieces of metadata: the Unique Identifier and the last modification date of the Publication.
When the taken together, the combined value represents a unique identity that can be used to distinguish any particular version of an EPUB Manifestation from another. To ensure that a Package Identifier can be constructed, the Publication must include exactly one [DCTERMS] modified property containing the last modification date (see meta). The value of this property must be an XML Schema [XSD-DATATYPES] dateTime conformant date of the form:
CCYY-MM-DDThh:mm:ssZ
The modification date must be expressed in Coordinated Universal Time (UTC) and must be terminated by the Z time zone indicator.
Although not a part of the package metadata, for referencing and other purposes this specification requires that all string representations of the identifier be constructed using the at sign (@) as the separator (i.e., of the form "id@date"). Whitespace must not be included when concatenating the strings.
The following example shows how a Unique Identifier and modification date are combined to form the Package Identifier.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
<meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
…
</metadata>
results in the Package ID:
urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809@2011-01-01T12:00:00Z
Note that it is possible that the separator character may occur in the Unique Identifier, as these identifiers may be any string value. The Package Identifier consequently must be split on the last instance of the at sign when decomposing it into its component parts.
The Package Identifier does not supersede the Unique Identifier, but represents the means by which different versions of the same Publication can be distinguished and identified in distribution channels and by Reading Systems. The sequential, chronological order inherent in the required format of the timestamp also places Publications in order without requiring knowledge of the exact identifier that came before.
The Package Identifier consequently allows a set of Publications to be inspected to determine if they represent the same version of the same Publication, different versions of a single Publication, or any combination of differing and similar Publications.
This section is informative
The property, properties, rel and scheme attributes use the property data type to represent terms from metadata vocabularies. Similar to a CURIE [RDFa10], the property data type represents an IRI [RFC3987] in compact form and simplifies the authoring of metadata from standardized vocabularies.
A property value is an expression that consists of a prefix and a reference, where the prefix — whether literal or implied — is a shorthand mapping of an IRI that typically resolves to a term vocabulary. When the prefix is converted to its IRI representation and combined with the reference, the resulting IRI normally resolves to a fragment within that vocabulary that contains human- and/or machine-readable information about the term.
To assist Reading Systems in processing property values, the means of establishing the IRI a prefix maps to is required, and this specification defines three such mechanisms:
a default vocabulary — defines the mapping when a property value does not include a prefix;
a set of reserved prefixes — these mappings are predefined (i.e., all Reading Systems recognize them) and can be used without having to be declared; and
the prefix attribute — a declarative means of creating new prefix mappings on the root package element.
The default vocabulary is a vocabulary that does not require a prefix to be declared in order to use its terms in package metadata, and whose terms must always be unprefixed.
To facilitate the inclusion of package metadata, this specification defines the Package Metadata Vocabulary as the default vocabulary for Package Documents.
If a property value does not include a prefix, the IRI [RFC3987] stem http://idpf.org/epub/vocab/package/# must be used to generate the resulting IRI.
The IRI associated with the Package Metadata Vocabulary must not be assigned a prefix using the prefix attribute.
This specification exclusively defines the following set of prefixes for use in package metadata.
| Prefix | IRI |
|---|---|
| dcterms | http://purl.org/dc/terms/ |
| marc | http://id.loc.gov/vocabulary/ |
| media | http://www.idpf.org/epub/vocab/overlays/# |
| onix | http://www.editeur.org/ONIX/book/codelists/current.html# |
| xsd | http://www.w3.org/2001/XMLSchema# |
The prefixes listed in the previous table must not be redeclared using the prefix attribute declaration mechanism. Similarly, the IRIs associated with each prefix must not be assigned to another prefix.
prefix AttributeThe prefix attribute defines additional prefix mappings not reserved by the specification.
The value of the prefix attribute is a whitespace-separated list of one or more prefix-to-IRI mappings of the form:
| prefixes | = | mapping , { whitespace, { whitespace } , mapping } ; | |
| mapping | = | prefix , ":" , space , { space } , ? xsd:anyURI ? ; | |
| prefix | = | ? xsd:NCName ? ; | |
| space | = | #x20 ; | |
| whitespace | = | (#x20 | #x9 | #xD | #xA) ; |
The following example shows prefixes for the Friend of a Friend (foaf) and DBPedia (dbp) vocabularies being declared using the prefix attribute.
<package … prefix="foaf: http://xmlns.com/foaf/spec/ dbp: http://dbpedia.org/ontology/"> … </package>
The prefix attribute must not be used to redefine the default vocabulary or the predefined prefixes.
The prefix '_' is reserved for future compatibility with RDFa [RDFa10] processing, so must not be defined.
The property data type is a compact means of expressing an IRI [RFC3987] and consists of an optional prefix separated from a reference by a colon.
| property | = | [ prefix , ":" ] , reference; | |
| prefix | = | ? xsd:NCName ? ; | |
| reference | = | ? irelative-ref ? ; | /* as defined in [RFC3987] */ |
The property data type is derived from the CURIE data type defined in [RDFa10], and represents a subset of CURIEs.
The following example shows a property value composed of the prefix dcterms and the reference modified.
<meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
After processing, this property would expand to the following IRI:
http://purl.org/dc/terms/modified
as the dcterms: prefix is a reserved prefix that maps to the IRI http://purl.org/dc/terms/.
When a prefix is omitted from the property value, the expressed reference represents a term from the default vocabulary.
The following example shows a property value taken from the default vocabulary.
<meta … property="role">aut</meta>
This property would expand to:
http://idpf.org/epub/vocab/package/#role
when the IRI for the default vocabulary is concatenated with the reference.
An empty string does not represent a valid property value, even though it is valid to the definition above.
A Reading System must use the following rules to create an IRI [RFC3987] from a property:
If the property consists only of a reference, the IRI is obtained by concatenating the IRI stem associated with the default vocabulary to the reference.
If the property consists of a prefix and reference, the IRI is obtained by concatenating the IRI stem associated with the prefix to the reference. If no matching prefix has been defined, the property is invalid.
The resulting IRI must be valid to [RFC3987]. Reading Systems are not required to resolve this IRI, however.
This section is informative
The following sections both define a set of properties for use in package metadata and constitute a referenceable vocabulary. This vocabulary is the default vocabulary reserved by this specification for the use of unprefixed terms in package metadata.
The properties defined in this vocabulary are referenceable using the base IRI http://idpf.org/epub/vocab/package/#.
meta PropertiesThe meta element properties enhance Publication metadata by providing additional level(s) of detail.
These properties must reference the expression or resource they augment in the refines attribute on their parent meta element.
The following tables detail the available properties.
› alternate-script | |
| Description: | The This property is typically attached to |
| Allowed value(s): | xsd:string |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | All properties. |
| Example: | <meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta> |
› display-seq | |
| Description: | The When the |
| Allowed value(s): | xsd:unsignedInt |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | All properties. |
| Example: | <meta refines="#t2" property="display-seq">1</meta> |
› file-as | |
| Description: | The file-as property provides the normalized form of the associated property for sorting. |
| Allowed value(s): | xsd:string |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | All properties. |
| Example: | <meta refines="#creator" property="file-as">Murakami, Haruki</meta> |
› group-position | |
| Description: | The The A Publication can belong to more than one group. |
| Allowed value(s): | A single xsd:unsignedInt or series of decimal-separated numbers (e.g., 1 or 2.2.1). |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | All properties. |
| Example: | <meta refines="#t3" property="group-position">2</meta> |
› identifier-type | |
| Description: | The When the |
| Allowed value(s): | xsd:string |
| Extends: | identifier |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Example: | <meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta> |
› meta-auth | |
| Description: | The meta-auth property provides the name of a party or authority responsible for an instance of package metadata. |
| Allowed value(s): | xsd:string |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | All properties. |
| Example: | <meta refines="isbn-id" property="meta-auth" id="meta-authority-01">Metadata Authority Inc.</meta> |
› role | |
| Description: | The When the |
| Allowed value(s): | xsd:string |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Extends: | contributor, creator |
| Example: | <meta refines="#creator" property="role" scheme="marc:relators">aut</meta> |
› title-type | |
| Description: | The When the |
| Allowed value(s): | xsd:string |
| Extends: | title |
| Cardinality: | In the metadata section: Attached to other metadata: |
| Example: | <meta refines="#title" property="title-type">main</meta> |
link PropertiesThe following tables define properties for use in the metadata link element rel attribute.
› marc21xml-record | |
| Description: | The marc21xml-record property indicates the referenced resource is a MARC21 record [MARC21XML]. |
| Cardinality: | Zero or one |
| Extends: | Only applies to the Publication. Must not be used when the refines attribute is present. |
| Example: | <link rel="marc21xml-record" href="pub/meta/nor-wood-marc21.xml"/> |
› mods-record | |
| Description: | The mods-record property indicates the referenced resource is a MODS record [MODS]. |
| Cardinality: | Zero or one |
| Extends: | Only applies to the Publication. Must not be used when the refines attribute is present. |
| Example: | <link rel="mods-record" href="pub/meta/nor-wood-mods.xml"/> |
› onix-record | |
| Description: | The onix-record property indicates the referenced resource is an ONIX record [ONIX]. |
| Cardinality: | Zero or one |
| Extends: | Only applies to the Publication. Must not be used when the refines attribute is present. |
| Example: | <link rel="onix-record" href="pub/meta/nor-wood-onix.xml"/> |
› xml-signature | |
| Description: | The The |
| Cardinality: | Zero or more |
| Extends: | All properties. |
| Example: | <link refines="#meta-authority-01" rel="xml-signature" href="../META-INF/signatures.xml#MAI-Signature"/> |
› xmp-record | |
| Description: | The xmp-record property indicates the referenced resource is an XMP record [XMP]. |
| Cardinality: | Zero or one |
| Extends: | Only applies to the Publication. Must not be used when the refines attribute is present. |
| Example: | <link rel="xmp-record" href="pub/meta/nor-wood-xmp.xml"/> |
item PropertiesThe following tables define properties for use in the manifest item element properties attribute.
The Applies to field indicates which Publication Resource type(s) the given property may be specified on, the Cardinality field indicates the number of times the property must appear within the Package Document scope, and the Usage field indicates usage conditions.
› cover-image | |
| Description: | The cover-image property identifies the described Publication Resource as the cover image for the Publication. |
| Applies to: | All raster and vector image types |
| Cardinality: | Zero or one |
| Usage: | Optional. |
› mathml | |
| Description: | The mathml property indicates that the described Publication Resource contains one or more instances of MathML markup. |
| Applies to: | EPUB Content Documents |
| Cardinality: | Zero or more |
| Usage: | Must be set if and only if the criterion specified in Description above is met. |
› | |
| Description: | The nav property indicates that the described Publication Resource constitutes the EPUB Navigation Document of the Publication. |
| Applies to: | The EPUB Navigation Document |
| Cardinality: | Exactly one |
| Usage: | Required. |
› remote-resources | |
| Description: | The (refer to Publication Resource Locations for more information). |
| Applies to: | All Publication Resources with the capability of internal referencing (e.g., XHTML Content Documents, SVG Content Documents, EPUB Style Sheets and Media Overlay Documents). |
| Cardinality: | Zero or more |
| Usage: | Must be set if and only if the criterion specified in Description above is met. |
› scripted | |
| Description: | The scripted property indicates that the described Publication Resource is a Scripted Content Document (i.e., contains scripted content and/or elements from HTML5 forms). |
| Applies to: | EPUB Content Documents |
| Cardinality: | Zero or more |
| Usage: | Must be set if and only if the criterion specified in Description above is met. |
› svg | |
| Description: | The svg property indicates that the described Publication Resource contains one or more instances of SVG markup. |
| Applies to: | XHTML Content Documents; the value is implied for SVG Content Documents. |
| Cardinality: | Zero or more |
| Usage: | Must be set if and only if the criterion specified in Description above is met. |
› switch | |
| Description: | The switch property indicates that the described Publication Resource contains one or more instances of the epub:switch element. |
| Applies to: | XHTML Content Documents. |
| Cardinality: | Zero or more |
| Usage: | Must be set if and only if the criterion specified in Description above is met. |
The mathml, remote-resources, scripted, svg and switch properties must be specified whenever the resource referenced by an item matches their respective definitions. These properties do not apply recursively to content included into a resource (e.g., via the HTML5 iframe element). For example, if a non-scripted XHTML Content Document embeds a scripted Content Document, only the embedded document's manifest item properties attribute will have the scripted value.
Examples
The following example shows a manifest item element that represents the cover image of a Publication.
<item properties="cover-image" id="ci" href="cover.svg" media-type="image/svg+xml" />
The following example shows a manifest item element representing a Scripted Content Document that also contains embedded MathML.
<item properties="scripted mathml" id="c2" href="c2.xhtml" media-type="application/xhtml+xml" />
itemref PropertiesThe following tables define properties for use in the itemref element properties attribute.
The Cardinality field indicates the number of times the property must appear within the Package Document scope, and the Usage field indicates usage conditions.
› page-spread-left | |
| Description: | The page-spread-left property indicates that the first page of the associated item's EPUB Content Document represents the left-hand side of a two-page spread. |
| Cardinality: | Zero or more |
| Usage: | Optional. This property must not be specified on an itemref that also specifies the page-spread-right property. |
› page-spread-right | |
| Description: | The page-spread-right property indicates that the first page of the associated item's EPUB Content Document represents the right-hand side of a two-page spread. |
| Cardinality: | Zero or more |
| Usage: | Optional. This property must not be specified on an itemref that also specifies the page-spread-left property. |
Examples
The following example shows how a two-page spread of a map might be indicated in the spine.
<spine> <itemref idref="title"/> <itemref idref="ps-1-l" properties="page-spread-left"/> <itemref idref="ps-1-r" properties="page-spread-right"/> <itemref idref="toc"/> … </spine>
The following table lists the EPUB 3 Core Media Types. When a Publication Resource conforms to a Core Media Type specification, it is a Core Media Type Resource and can be included in the Publication without the provision of fallbacks (refer to Restrictions and Fallbacks for more information).
The columns in the table represent the following information:
The MIME media type [RFC2046] used to represent the given Publication Resource in the manifest.
The specification to which the given Core Media Type Resource must conform.
The Publication Resource type(s) that the Media Type and Content Type Definition applies to.
| Media Type | Content Type Definition | Applies to |
|---|---|---|
| Image Types | ||
image/gif | [GIF] | GIF Images |
image/jpeg | [JPEG] | JPEG Images |
image/png | [PNG] | PNG Images |
image/svg+xml | SVG Content Documents [ContentDocs30] | SVG documents |
| Application Types | ||
application/xhtml+xml | XHTML Content Documents [ContentDocs30] | XHTML Content Documents and the EPUB Navigation Document. |
application/x-dtbncx+xml | [OPF2] | The superseded NCX |
application/vnd.ms-opentype | [OpenType] | OpenType fonts |
application/font-woff | [WOFF] | WOFF fonts |
application/smil+xml | [MediaOverlays30] | EPUB Media Overlay documents |
application/pls+xml | [PLS] | Text-to-Speech (TTS) Pronunciation lexicons |
| Audio Types | ||
audio/mpeg | [MP3] | MP3 audio |
audio/mp4 | [AAC LC], [MP4] | AAC LC audio using MP4 container |
| Text Types | ||
text/css | EPUB Style Sheets [ContentDocs30] | EPUB Style Sheets. |
text/javascript | [RFC4329] | Scripts |
This specification does not define any video codecs as Core Media Types. Refer to the note in EPUB Publications — Reading System Conformance above for informative recommendations on support for video codecs in EPUB Publications.
All Publication Resources of an EPUB Publication must be Core Media Type Resources or must provide a Core Media Type fallback. The cases in which Foreign Resource may be used, and the requirement and rules for Core Media Type fallback provision in such cases, are detailed below.
› Foreign Resources may be referenced from EPUB Content Document elements that have explicit intrinsic fallback mechanisms (e.g., the [HTML5] object, canvas, audio and video elements). A Core Media Type resource must be provided via the given element's intrinsic fallback mechanism in such cases.
› For the [HTML5] video element, the image referenced by the poster attribute and text content embedded within the video element are also considered valid Core Media Type fallbacks in addition to the video element's intrinsic fallback capabilities. For the purpose of providing a last resort fallback for Reading Systems that do not support video or the given video format(s), at least one of these should be included with each occurrence of the video element.
› For the [HTML5] audio element, text content embedded within the element is also considered a valid Core Media Type fallback in addition to the audio element's intrinsic fallback capabilities. For the purpose of providing a last resort fallback for Reading Systems that do not support audio, embedded text content should be included with each occurrence of the audio element.
› In this version of this specification, the [HTML5] track element is exempt from the Core Media Type usage rule: Foreign Resources may be referenced from track without the provision of a Core Media Type fallback.
› Fonts embedded in Content Documents or EPUB Style Sheets using the @font-face mechanism may be Foreign Resources. Reading Systems must use the rules for matching font styles [CSS3Fonts] when identifying a fallback for an unsupported font type.
› Foreign Resources may be referenced directly from spine itemref elements, and in this case Manifest fallbacks must be provided.
Fallbacks must be provided for each Publication Resource referenced in a spine itemref element that is not an EPUB Content Document.
Fallbacks are provided using the fallback attribute on the manifest item element that represents the Publication Resource. The fallback attribute's IDREF [XML] value must resolve to another item in the manifest. This fallback item may itself specify another fallback item, and so on.
The ordered list of all the ID references that can be reached starting from a given item's fallback attribute represents the fallback chain for that item. The order of the resources in the fallback chain represents the Authors' preferred fallback order.
A Reading System that does not support the Media Type of a given Publication Resource must traverse the fallback chain until it has identified at least one supported Publication Resource to be used in place of the unsupported resource. If the Reading System supports multiple Publication Resources in the fallback chain, it may select the resource to use based on specific properties of that resource, otherwise it should honor the Authors' preferred fallback order.
A fallback chain must contain at least one EPUB Content Document and must not contain any circular- or self-references to items in the chain.
Fallbacks may also be provided for Top-level Content Documents that are EPUB Content Documents; a Reading System may choose to utilize such fallbacks in order to find the optimal version of a Content Document to render in a given context. An example of when this feature can be utilized is when providing fallbacks for scripted content [ContentDocs30].
All Publication Resources must be located in the EPUB Container, with the following exceptions:
› Audio resources may be located in the Container or remotely.
› Video resources may be located in the Container or remotely.
Authors should prefer locating audio and video resources in the Container to allow the user access to the entire presentation regardless of connectivity status.
The above rules for Publication Resource locations apply regardless of whether the given resource is a Core Media Type Resource or a Foreign Resource.
The inclusion of remote resources in an EPUB Publication is indicated via the remote-resources property on the manifest item element.
Any Publication Resource that is an XML-Based Media Type must meet the following constraints:
› It must be a conformant XML 1.0 Document as defined in Conformance of Documents [XMLNS].
› External identifiers must not appear in the document type declaration [XML].
› It must not make use of XInclude [XInclude].
The above constraints apply regardless of whether the given Publication Resource is a Core Media Type Resource or a Foreign Resource.
The schema for Package Documents is available at http://www.idpf.org/epub/30/schema/package-30.nvdl.
This schema is normative.
Validation using this schema will require a processor that supports [NVDL], [RelaxNG] and [ISOSchematron].
Note, however, that the NVDL schema layer can be substituted by a multi-pass validation using the embedded RELAX NG and ISO Schematron schemas alone.
application/oebps-package+xml Media TypeThis appendix registers the media type application/oebps-package+xml for the EPUB Package Document. This registration supersedes [RFC4839].
The Package Document is an XML file that describes an EPUB Publication [Publications30]. It identifies the resources in the Publication and provides metadata information. The Package Document and its related standards are maintained and defined by the International Digital Publishing Forum (IDPF).
application
oebps-package+xml
None.
None.
Package Documents are UTF-8 or UTF-16 encoded XML.
Package Documents contain well-formed XML conforming to the XML 1.0 specification.
Clearly, it is possible to author malicious files which, for example, contain malformed data. Most XML parsers protect themselves from such attacks by rigorously enforcing conformance.
All processors that read Package Documents should rigorously check the size and validity of data retrieved.
There is no current provision in the EPUB Publications 3.0 standard for encryption, signing, or authentication within the Package Document format.
None.
This media type registration is for the EPUB Package Document, as described by the EPUB Publications 3.0 specification located at http://www.idpf.org/epub/30/spec/epub30-publications.html.
The EPUB Publications 3.0 specification supersedes the Open Packaging Format 2.0.1 specification, which is located at http://idpf.org/epub/20/spec/OPF_2.0.1_draft.htm and which also uses the application/oepbs-package+xml media type.
This media type is in wide use for the distribution of ebooks in the EPUB format. The following list of applications is not exhaustive.
Adobe Digital Editions
Aldiko
Azardi
Apple iBooks
Barnes & Noble Nook
Calibre
Google Books
Ibis Reader
MobiPocket reader
Sony Reader
Stanza
none
.opf
TEXT
The IDPF maintains a registry of linking schemes at http://idpf.org/epub/linking/. Some of these schemes define custom fragment identifiers that resolve to application/oebps-package+xml documents.
William McCoy, [email protected]
COMMON
International Digital Publishing Forum (http://www.idpf.org)
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].
[AAC LC] ISO/IEC 14496-3:2009 - Information technology -- Coding of audio-visual objects -- Part 3: Audio .
[ASSOCSS] Associating Style Sheets with XML documents 1.0 (Second Edition) . 28 October 2010.
[CSS3Fonts] CSS Fonts Module Level 3 .
[ContentDocs30] EPUB Content Documents 3.0 .
[DCTERMS] DCMI Metadata Terms .
[ISOSchematron] ISO/IEC 19757-3: Rule-based validation — Schematron .
[MARC21XML] MARC 21 XML Schema .
[MediaOverlays30] EPUB Media Overlays 3.0 .
[OCF2] Open Container Format 2.0.1 .
[OCF3] Open Container Format 3.0 .
[ONIX] ONIX for Books .
[OPF2] Open Packaging Format 2.0.1 .
[OPS2] Open Publication Structure 2.0.1 .
[OpenType] ISO/IEC 14496-22:2009 - Information technology -- Coding of audio-visual objects -- Part 22: Open Font Format .
[PLS] Pronunciation Lexicon Specification 1.0 (PLS) . 14 October 2008.
[PNG] Portable Network Graphics (PNG) Specification (Second Edition) . 10 November 2003.
[Publications30] EPUB Publications 3.0 .
[RDFa10] RDFa in XHTML: Syntax and Processing . A collection of attributes and processing rules for extending XHTML to support RDF. 14 October 2008.
[RFC2046] Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types (RFC 2046) . November 1996.
[RFC2119] Key words for use in RFCs to Indicate Requirement Levels (RFC 2119) . March 1997.
[RFC3987] Internationalized Resource Identifiers (IRIs) (RFC 3987) . January 2005.
[RFC4839] Media Type Registrations for the Open eBook Publication Structure (OEBPS) Package File (OPF) (RFC 4839) . April 2007.
[RFC5646] Tags for Identifying Languages (RFC 5646) . September 2009.
[RelaxNG] ISO/IEC 19757-2: Regular-grammar-based validation — RELAX NG. Second Edition . 2008-12-15.
[Unicode] The Unicode Consortium. The Unicode Standard, Version 5.0.0, defined by: The Unicode Standard, Version 5.0 (Boston, MA, Addison-Wesley, 2007. ISBN 0-321-48091-0).
[WOFF] WOFF File Format 1.0 .
[XInclude] XML Inclusions (XInclude) Version 1.0 (Second Edition) . 15 November 2006.
[XML] Extensible Markup Language (XML) 1.0 (Fifth Edition) . 26 November 2008.
[XML Base] XML Base (Second Edition) . 28 January 2009.
[XML DSIG Core] XML-Signature Syntax and Processing Version 1.1 . 3 March 2011.
[XMLNS] Namespaces in XML (Third Edition) . 8 December 2009.
[XMP] Extensible Metadata Platform .
[XSD-DATATYPES] XML Schema Part 2: Datatypes Second Edition . 28 October 2004.
[EPUB3Changes] EPUB 3 Differences from EPUB 2.0.1 .
[EPUB3Overview] EPUB 3 Overview .
[RFC4329] Scripting Media Types . April 2006.