Copyright © 2019 W3C® (MIT, ERCIM, Keio, Beihang). W3C liability, trademark and permissive document license rules apply.
This specification describes the requirements for the creation of audiobooks, using a profile of the Publication Manifest specification.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.
This draft is still under consideration within the Publishing Working Group and is subject to change. The most prominent issues will be referenced in the document with links provided.
This document was published by the Publishing Working Group as a Working Draft. This document is intended to become a W3C Recommendation.
GitHub Issues are preferred for discussion of this specification. Alternatively, you can send comments to our mailing list. Please send them to public-publ-wg@w3.org (archives).
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This document is governed by the 1 March 2019 W3C Process Document.
This section is non-normative.
An Audiobook is a collection of audio resources grouped together by a reading order, metadata, and resources, all contained in a manifest. This Audiobook can live on the Open Web Platform, or as a packaged entity.
This specification is intended to standardize the audiobooks distribution model on the web and between businesses. It should facilitate different user agent architectures for the consumption of Audiobooks. The primary goal is to bring clarity to a part of the publishing industry currently underserved by standards, while opening Audiobooks to the Open Web Platform and new user agents. This specification does not outline what file types or formats should be used by content creators, only a manifest format for delivering them.
This specification does not define how user agents are expected to render Audiobooks. Details about the types of affordances that user agents can provide to enhance the reading experience for users are instead defined in [PWP-UCR].
Terms with meanings specific to the publishing industry are capitalized in this document (e.g., "Reading System"). A complete list of these terms and definitions is provided in [pub-manifest].
Only the first instance of a term in a section is linked to its definition.
In addition, the following terminology is defined for use in this specification:
Supplemental content is any content relating to the audiobook content but not required for the full experience of the publication. Examples of supplemental content include photographs, charts, or data relating to topics mentioned in the audiobook.
As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.
The key words MAY, MUST, MUST NOT, RECOMMENDED, REQUIRED, and SHOULD in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
The primary entry page represents the preferred starting resource for an Audiobook and enables discovery of its manifest.
The primary entry page is an HTML resource that typically introduces the audiobook and provides access to the content. It SHOULD contain the table of contents.
It is not required that the primary entry page be included in the default reading order, as the Audiobooks profile requires that only audio resources be present. The primary entry page should instead, if present, be included as a resource.
The table of contents provides a hierarchical list of links that reflects the structural outline of the major sections of the Audiobook and any supplemental content it may contain.
The table of contents is expressed via an [html] element (typically a nav element) in one of the resources. This element MUST be identified by the role attribute [html] value "doc-toc" [dpub-aria-1.0].
If the table of contents is located in the primary entry page, the table of contents MUST be the first element in the document — in document tree order [dom] — with that role value. Otherwise, the manifest SHOULD identify the resource that contains the structure.
If the table of contents is not located in the primary entry page, the manifest SHOULD identify the resource that contains the structure.
When an Audiobook contains additional resources (i.e. supplemental content):
a table of contents SHOULD be included;
the table of contents SHOULD include a link to any of the resources; and
and all links SHOULD refer to publication resources [pub-manifest].
When including supplemental content, be aware that users might not have access to this content unless it is linked to from the table of contents. It is strongly advised to provide links to all content that is not in the default reading order.
This section is non-normative.
The Audiobook manifest is defined by a set of properties that describe the basic information a user agent requires to process and render an Audiobook. These properties are categorized in the Publication Manifest [pub-manifest]. Where these properties are extended from the Publication Manifest is specified in this section.
An Audiobook manifest has to start by setting the JSON-LD context [json-ld]. The context has the following two major components:
https://schema.orghttps://www.w3.org/ns/pub-context{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
…
}To add the global language and direction of the manifest metadata, language and direction declaration [pub-manifest] can also be added to the context:
{
"@context" : [
"https://schema.org",
"https://www.w3.org/ns/pub-context",
{"language":"fr"}
]
...
}The conformance URL expressed in the conformsTo term [pub-manifest] MUST be "https://www.w3.org/TR/audiobooks".
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/"
…
}The Publication Type is defined using the type term [pub-manifest].
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/wp-context"],
"type" : "Audiobook"
…
}If a type is not specified, Audiobook [schema.org] is assumed as the default.
The requirements for the expression of Audiobook properties are defined as follows:
Some properties are implicitly required, as they are compiled from alternative information when not explicitly authored. Refer to the internal representation data models [pub-manifest] for more information (the Audiobooks representation only differs in the default value for the type term).
A creator is an individual or entity responsible for the creation of the Web Publication. The Audiobooks profile can use the full list of creators specified in Web Publications.
The creators list includes two recommended creators for Audiobooks:
{
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"@context" : ["https://schema.org","https://www.w3.org/ns/pub-context"],
"type" : "Audiobook",
…
"url" : "https://publisher.example.org/janeeyre",
"author" : {
"type" : "Person",
"name" : "Charlotte Bronte"
}
}{
"conformsTo" : "https://www.w3/org/TR/audiobooks/";
"@context": ["https://schema.org", "https://www.w3.org/ns/pub-context"],
…
"url" : "https://publisher.example.org/janeeyre",
"author" : {
"type": "Person",
"name": "Charlotte Bronte"
}
"readBy" : {
"type": "Person",
"name": "Ivan Herman",
"id" : "https://www.w3.org/People/Ivan/"
}
}A duration is the length of the audio resources in an Audiobook. The duration property is fully defined in the Publication Manifest specification.
Duration SHOULD be expressed for the entirety of the audiobook as part of the manifest, and SHOULD be present at the item level in the default reading order.
When a content creator specifies both the duration for the audiobook and item-level duration in the default reading order the resource-level duration SHOULD be equal to the sum of the durations of the items in the reading order.
{
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"@context" : ["https://schema.org","https://www.w3.org/ns/pub-context"],
…
"url" : "https://publisher.example.org/janeeyre",
"author" : {
"type" : "Person",
"name" : "Charlotte Bronte"
},
"duration" : "PT12345.235S"
}The default reading order is a specific progression through the audio resources in the audiobook.
The default reading order MUST contain at least one audio resource, which MAY be identified by the type of LinkedResource. The default reading order MUST NOT contain non-audio resources.
An audio resource can be referenced in its entirety via a URL [url], or for content where multiple chapters occupy a single file by using media fragments [media-frags] to locate the exact starting point.
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"readingOrder" : [{
"type" : "LinkedResource",
"url" : "audio/janeeyre.mp3",
"encodingFormat" : "audio/mp3",
"name" : "Jane Eyre",
"duration" : "PT124503.123S"
}]
}{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"readingOrder" : [{
"type": "LinkedResource",
"url" : "audio/part001.wav#0",
"encodingFormat" : "audio/vnd-wav",
"name" : "Chapter 1",
"duration" : "PT457.931S"
}, {
"type" : "LinkedResource",
"url" : "audio/part001.wav#457.932",
"encodingFormat" : "audio/vnd-wav",
"name" : "Chapter 2",
"duration" : "PT234.245S"
}]
}The resource list enumerates any additional resources used in the processing and rendering of an audiobook that are not listed in the reading order. It is expressed using the resources property.
If an audiobook includes supplemental content it MUST be referenced in the resource list.
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"resources" : [
"cover.jpg",
"portrait_CB.jpg",
"supplement.pdf"
]
}Previews are a common way to provide users an experience of the full content before purchasing or downloading the full audiobook.
A preview is identified using the preview link relation, as defined in [pub-manifest].
Previews MAY be located externally or included as a resource of the audiobook.
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"resources" : [{
"type" : "LinkedResource",
"url" : "https://publisher.example.org/jane-eyre-preview.wav",
"encodingFormat" : "audio/wav",
"rel" : "preview"
}]
}{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"resources" : [{
"type" : "LinkedResource",
"url" : "preview.wav",
"encodingFormat" : "audio/wav",
"rel" : "preview"
}]
}This section is non-normative.
Audiobooks will be packaged using the method described in the Lightweight Packaging Format note.
This section is non-normative.
The history of the audiobook is rooted in the world of accessibility. To create a fully accessible audiobook, it is recommended to use the Synchronized Media note to create documents where text and audio can be completely synchronized.
To create an accessible audiobook using Synchronized Media, you need to both reference the alternative file on the item in the reading order, as well as list the file in the resources.
Alternatively, a content creator can provide the text equivalent as HTML [html] resources in the resources.
At the time of this publication, a Synchronized Media specification suitable for use in audiobooks is in development. It is believed this specification can already meet synchronization needs, though reliance on a developing specification clearly carries no guarantee of backward compatibility. Participation and comments from the digital publishing community, and especially from implementors are encouraged.
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"readingOrder" : [{
"type" : "LinkedResource",
"url" : "audio/part001.wav",
"encodingFormat" : "audio/vnd-wav",
"name" : "Chapter 1",
"duration" : "PT457.931S",
"alternate" : {
"type" : "LinkedResource",
"url" : "sync-media/part001-1.json",
"encodingFormat" : "application/vnd.wp-sync-media+json"}
}, {
"type" : "LinkedResource",
"url" : "audio/part001.wav#t=457.932",
"encodingFormat" : "audio/vnd-wav",
"name" : "Chapter 2",
"duration" : "PT234.245S",
"alternate" : {
"type" : "LinkedResource",
"url" : "sync-media/part001-2.json",
"encodingFormat" : "application/vnd.wp-sync-media+json"}
}],
"resources" : [{
"type": "LinkedResource",
"url": "sync-media/part001-1.json",
"encodingFormat" : "application/vnd.wp-sync-media+json"
}, {
"type": "LinkedResource",
"url" : "sync-media/part001-2.json",
"encodingFormat" : "application/vnd.wp-sync-media+json"
}...
]
}{
"@context" : ["https://schema.org", "https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"url" : "https://publisher.example.org/janeeyre",
"name" : "Jane Eyre",
"readingOrder" : {
"type" : "LinkedResource",
"url" : "audio/part001.wav#0",
"encodingFormat" : "audio/vnd-wav",
"name" : "Chapter 1",
"duration" : "PT457.931S",
"alternate" : {
"type" : "LinkedResource"
"url" : "text/part001-1.html",
"encodingFormat" : "text/html"}
},
"resources" : [{
"type": "LinkedResource",
"url": "text/part001-1.html",
"encodingFormat" : "text/html"
}...
]
}This section depends on the Infra Standard [infra].
The specification extends the Publication Manifest processing algorithms [pub-manifest] as follows:
The following extension steps are added for Audiobook manifests:
(§ 4.1 Primary Entry Page and § 4.2 Table of Contents) If document is not defined or does not include an [html] element with the role doc-toc:
let toc be a boolean value set to false.
for each
resource of processed["resources"], if resource["rel"] is defined and contains the value contents, set toc to true, then break.
if toc is not true, validation error.
The following extension steps are added for Audiobook manifests:
(§ 5.6 Default Reading Order) Check the reading order as follows:
if data["readingOrder"] is not set or is an empty list, fatal error, return failure. Otherwise, if data["readingOrder"] does not contain at least one item with an audio media type, fatal error, return failure.
otherwise, for each resource in data["readingOrder"], if resource is not an audio resource, validation error, remove resource from data["readingOrder"].
(§ 5.4 Publication Type) If data["type"] is not set or is an empty list, validation error, set to « "Audiobook" ».
(§ 5.5.1 Requirements) Check that each of the following properties is set. If not, issue a validation error for each one.
(§ 5.5.1 Requirements) If no resource in data["readingOrder"] or data["resources"] has a rel
entry that contains the relation cover, validation error.
(§ 5.5.3 Duration) Check the duration of the publication as follows:
Let resourceDuration hold the total duration of individual resources.
For each resource of data["readingOrder"]:
if resource["duration"] is not defined, validation error.
otherwise, if resource["duration"] is not a valid duration value, per [iso8601], validation error, remove resource["duration"].
otherwise, add resource["duration"] to resourceDuration.
If data["duration"] is not set, validation error. Otherwise, if resourceDuration does not specify the same total duration as data["duration"], validation error.
As Audiobooks is a profile of Publication Manifest [pub-manifest], all security and privacy considerations detailed in that specification are applicable to this profile.
This profile acknowledges the following considerations:
This section is non-normative.
This section outlines the expected user agent behaviours for implementation of audiobooks. For processing instructions, user agents should refer to the Processing a Manifest section of the Publication Manifest specification, and conform to any behaviour described there.
All user agent behaviours described in this section are intended to provide implementors with guidance, not strict requirements. Behaviours in this document are taken mainly from the Use Cases and Requirements note published by the working group.
As outlined in the Use Cases and Requirements note, an audiobook must be navigable in the User Agent. This means that a User Agent must provide methods for the user to move through the audiobook in a linear or non-linear fashion by either moving through the Reading Order seamlessly or by accessing the Table of Contents. The User Agent should also allow the user to move through individual audio files in short time increments.
For an audiobook, the User Agent should provide a player interface that will allow the user to navigate, play, or pause the audiobook. This interface can be represented to the user in any way (i.e. physical buttons, visual interface, keyboard input, or voice commands), but should be accessible at any point in the listening experience.
The Use Cases and Requirements note recommends that content be available offline and that any packaged formats should not affect the iterations of the publications. This means that even if the content is copied many times to many users via multiple User Agents, the core manifest and it's identifier are never changed.
This specification recommends the Lightweight Packaging Format for packaging audiobook content, but this is not a requirement. Audiobook User Agents should be able to ingest LPF files for play, and should display content according to the requirements and recommendations in this document.
If a User Agent is serving the content directly from their service (i.e. as a retailer or repository of content), it is recommended that they provide a method for offlining or downloading the content to the user. This can be in any format they choose, but the audiobook should be complete and valid and the contents listed in the manifest should be served in their entirety. Even if a User Agent does not support the display of a certain resource (i.e. an image file or data table), it should still be available to the user for download.
This specification does not provide a method for content creators to protect or watermark their content, as there are existing methods available in the market today. User Agents who work with content creators that wish to protect or limit the distribution of their content can choose a method that works best for their requirements.
This specification recommends and provides a method for content creators to create fully accessible audiobooks. User Agents should use this information, in the section on Accessibility, to implement accessible audiobook interfaces. It is recommended that User Agents provide accessible player interfaces, as well as a method for content creators who have provided alternate content to have that content displayed.
This section is non-normative.
A manifest for an audiobook. The canonical version of this manifest is also available.
{
"@context": ["https://schema.org", "https://www.w3.org/ns/wp-context"],
"type": "Audiobook",
"id": "https://librivox.org/flatland-a-romance-of-many-dimensions-by-edwin-abbott-abbott/",
"url": "https://w3c.github.io/wpub/experiments/audiobook/",
"name": "Flatland: A Romance of Many Dimensions",
"author": "Edwin Abbott Abbott",
"readBy": "Ruth Golding",
"publisher": "Librivox",
"inLanguage": "en",
"dateModified": "2018-06-14T19:32:18Z",
"datePublished": "2008-10-12",
"duration": "PT15153S",
"license": "https://creativecommons.org/publicdomain/zero/1.0/",
"resources": [
{
"rel": "cover",
"url": "http://ia800704.us.archive.org/9/items/LibrivoxCdCoverArt12/Flatland_1109.jpg",
"encodingFormat": "image/jpeg"
},{
"rel": "contents",
"url": "toc.html",
"encodingFormat": "text/html"
}
],
"readingOrder": [
{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_1_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1371,
"name": "Part 1, Sections 1 - 3"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_2_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1669,
"name": "Part 1, Sections 4 - 5"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_3_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1506,
"name": "Part 1, Sections 6 - 7"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_4_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1669,
"name": "Part 1, Sections 8 - 10"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_5_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1506,
"name": "Part 1, Sections 11 - 12"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_6_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1798,
"name": "Part 2, Sections 13 - 14"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_7_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1225,
"name": "Part 2, Sections 15 - 17"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_8_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1371,
"name": "Part 2, Sections 18 - 20"
},{
"url": "http://www.archive.org/download/flatland_rg_librivox/flatland_9_abbott.mp3",
"encodingFormat": "audio/mpeg",
"duration": 1659,
"name": "Part 2, Sections 21 - 22"
}
]
}
A manifest for an audiobook with supplemental content.
{
"@context" : ["https://schema.org", "https://www.w3/org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
"id" : "https://publisher.example.com/janeeyre",
"url" : "https://publisher.example.com/janeeyre",
"name" : "Jane Eyre",
"author" : "Charlotte Bronte",
"readBy" : "Jane Doe",
"duration" : "PT123456.789S",
"abridged" : "false",
"inLanguage" : "en",
"dateModified" : "2019-03-29T15:59:00Z",
"datePublished" : "2019-03-29",
"readingOrder": [
{"url": "audio/chapter001.aac", "encodingFormat": "audio/aac", "name": "Chapter 1", "duration": "PT1234.567S"},
{"url": "audio/chapter002.aac", "encodingFormat": "audio/aac", "name": "Chapter 2", "duration": "PT890.123S"},
{"url": "audio/chapter003.aac", "encodingFormat": "audio/aac", "name": "Chapter 3", "duration": "PT456.789S"},
{"url": "audio/chapter004.aac", "encodingFormat": "audio/aac", "name": "Chapter 4", "duration": "PT987.654S"},
{"url": "audio/chapter005.aac", "encodingFormat": "audio/aac", "name": "Chapter 5", "duration": "PT321.987S"}
],
"resources": [
{"rel": "cover", "url": "images/cover.jpg", "encordingFormat": "image/jpeg"},
{"rel": "contents", "url": "toc.html", "encodingFormat": "text/html"},
{"url": "haworth_house.pdf", "encodingFormat": "application/pdf"}
]
}This section is non-normative.
A primary entry page with a simple table of contents for an audiobook.
<head>
…
<script type="application/ld+json">
{
"@context" : ["https://schema.org","https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3/org/TR/audiobooks/",
…
"url" : "https://publisher.example.org/janeeyre",
…
}
</script>
…
</head>
<body>
…
<section role="doc-toc">
<ol>
<li><a href="audio/chapter001.wav">Chapter 1. There was no possibility of taking a walk that day...</a></li>
<li><a href="audio/chapter002.wav">Chapter 2. I resisted all the way:...</a></li>
<li><a href="audio/chapter003.wav">Chapter 3. The next thing I remember is,...</a></li>
…
</ol>
</section>
…
</body>A table of contents for a simple audiobook.
<nav role="doc-toc">
<h2>JANE EYRE</h2>
<ol>
<li><a href="audio/chapter001.mp3">Chapter 1. There was no possibility of taking a walk that day...</a></li>
<li><a href="audio/chapter002.mp3">Chapter 2. I resisted all the way:...</a></li>
<li><a href="audio/chapter003.mp3">Chapter 3. The next thing I remember is,...</a></li>
…
</ol>
</nav>A table of contents using media fragment references to locations in a single audio track.
<nav role="doc-toc">
<h2>JANE EYRE</h2>
<ol>
<li><a href="https://example.publisher.org/janeeyre/part001.mp3">Chapter 1</a></li>
<li><a href="https://example.publisher.org/janeeyre/part001.mp3#t=456.789">Chapter 2</a></li>
<li><a href="https://example.publisher.org/janeeyre/part001.mp3#t=1234.567">Chapter 3</a></li>
</ol>
</nav>This section is non-normative.
The editor would like to thank the members of the Publishing Working Group for their contributions to this specification:
The Working Group would also like to thank the members of the Digital Publishing Interest Group for all the hard work they did paving the road for this specification.