Other techniques for implementing EPUB accessibility metadata are available: Display Techniques for Displaying Accessibility Metadata
This document provides techniques for meeting the guidelines of the User Experience Guide for Displaying Accessibility Metadata. It provides practical examples for extracting information from the ONIX metadata for showing it to the end users.
ONIX messages describe products for the global book supply chain and will be sent from publisher or creator of the epub or digital books with full audio to those who will make the products available for sale, lending or subscription. These platforms may not yet have the actual files, as they may not yet be ready, or may only choose to list them for sale if they have certain accessibility features. ONIX also only describes a product, it cannot describe the features of the reading systems on which a product may be accessed. It is important to use ONIX metadata as a complement to the accessibility data embedded within the publication itself, if describing accessible books, books with full audio and related products for the global book supply chain. An ONIX file can be used to display accessibility information in advance of publication or when you do not have access to the metadata in the digital file itself. Some accessibility information may only be available when you have access to the file itself. If you are unfamiliar with ONIX, then there is more documentation available from EDItEUR.org.
ONIX does not have a 1:1 mapping with EPUB accessibility metadata. As some accessibility assertions are posed differently between the two mechanisms, direct mapping between the two may not always be possible. The EPUB to ONIX crosswalk outlines the current high degree of overlap in metadata and will be updated as these two specifications evolve. It is important to note that ONIX 3.0 includes a number of new accessibility metadata codes, some of which may not be expressible in earlier versions of ONIX.
Here is an example of an ONIX record (version 3.0), which will be used as a reference point for the following examples on EPUB accessibility metadata: the results of the XPath shown are based on this example.
Here is an example of an ONIX record (version 3.0) for describing an audiobook, which will be used as a reference point for the some of the following examples on EPUB accessibility metadata: the results of the XPath shown are based on this example.
Value: Yes / No / Unknown
This technique relates to Screen Reader Friendly principle.
This information can be retrieved from ONIX List 81; Code: 10 combined with code list 196; Code: 10 means all text is actual text.
List 81; Code: 10 on its own (without List 196; Code: 10) admits the possibility that the ‘text’ is inaccessible because it is an image of text.
This field is true if the both XPath elements exist:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Screen Reader Friendly: Yes
Values: Yes / (if No - Omit this section)
This technique relates to Full Audio principle.
If the publication is based on text with synchronized audio, this information can be retrieved from ONIX code list: 196; Code: 20: Synchronised pre-recorded audio.
If the publication is audio-only (e.g. audiobook), this information can be retrieved from ONIX code list 81; Code: 01: Audiobook.
If the following XPath returns at least one result:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Full Audio: Yes
This field is true if the XPath returns one element for:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 2.
Full Audio: Yes
Value: Textual Data from metadata
This technique relates to Accessibility Summary principle.
This information can be retrieved from ONIX code list: 196; Code: 00: Accessibility Summary.
The value can be retrieved using XPath:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Accessibility Summary:
This publication includes markup to enable accessibility and compatibility with assistive technology. Images, audio, and video in the publication are well-described in conformance with WCAG 2.0 A.
Value: Textual Link based on Metadata
This technique relates to Accessibility Conformance principle.
If the following XPath returns at least one result:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Accessibility Conformance: EPUB Accessibility, WCAG-A
If the following XPath returns at least one result:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Accessibility Conformance: EPUB Accessibility, WCAG-AA
Value: Textual Data from metadata
This technique relates to Certified By principle.
List: 196; Code: 93: Compliance certification by
The value can be retrieve using XPath:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Certified By: http://www.certifier.com/
Value: Potentially linked textual data from metadata
This technique relates to Certifier Credential principle.
Not available in ONIX
Value: Potentially linked textual data from metadata
This technique relates to Certifier Report principle.
List: 196; Code: 94: Compliance web page for detailed accessibility information
Or
If it is certified by a trusted intermediary, List: 196; Code: 95: Trusted intermediary’s web page for detailed accessibility information
Or
If a publisher is self-certifying, List: 196; Code: 96: Publisher’s web page for detailed accessibility information
The value can be retrieve using XPath:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Certifier Report
Or
Values: flashing, motion simulation, sound, no flashing, no motion simulation, no sound, none, or Unknown.
This technique relates to Hazards principle.
ONIX uses a composite to indicate different hazards.
To list the presence or absence of hazards it is used the ProductFormFeature element, with ProductFormFeatureType equal to 12 ("US CPSIA or other international hazard warning", from code list 79) and ProductFormFeatureValue from code list 143.
The value can be retrieve using XPath:
For this example, this XPath was evaluated on the ONIX record presented in EXAMPLE 1.
Hazard: no Flashing, no Sound, no Motion Simulation
(because ProductFormFeature with ProductFormFeatureType equal to 12 and ProductFormFeatureValues equal to: 14, 16, 18)
Value: Link to complete list of all metadata fields
This technique relates to All Accessibility Metadata principle.
For a complete list of ONIX accessibility metadata refer to the crosswalk.