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NLS: That All May Read

Business Plan 2003
Appendix 3

Excerpts from
ANSI/NISO Z39.86-2002
Specifications for the Digital Talking Book

Used with permission of the National Information Standards Organization (NISO).

Publication information

Foreword

NISO Voting Members

NISO Board of Directors

Standards Committee AQ Members

Overview

Link to full standard

ANSI/NISO Z39.86-2002
ISSN: 1041-5653

Abstract: This standard defines the format and content of the electronic file set that comprises a digital talking book (DTB) and establishes a limited set of requirements for DTB playback devices. It uses established and new specifications to delineate the structure of DTBs whose content can range from XML text only, to text with corresponding spoken audio, to audio with little or no text. DTBs are designed to make print material accessible and navigable for blind or otherwise print-disabled persons.

An American National Standard Developed by the National Information Standards Organization
Approved March 6, 2002, by the American National Standards Institute

Copyright ©2002 by the National Information Standards Organization.
All rights reserved under international and Pan-American Copyright Conventions. For noncommercial purposes only this publication may be reproduced or transmitted in any form or by any means without prior permission in writing from the publisher. All inquiries regarding commercial reproduction or distribution should be addressed to NISO Press, 4733 Bethesda Avenue, Suite 300, Bethesda, MD 20814 USA.

ISSN: 1041-5653 National Information Standards Series
ISBN: 1-880124-52-1

Foreword

(This foreword is not a part of ANSI/NISO Z39.86-2002, Specifications for the Digital Talking Book. It is included for information only.)

This standard presents specifications for digital talking books (DTBs) for blind, visually impaired, physically handicapped, learning-disabled, or otherwise print-disabled readers. For many years, "talking books" have been made available to print-disabled readers on analog media such as phonograph records and audiocassettes. These media serve their users well in providing human-speech recordings of a wide array of print material in increasingly robust and cost-effective formats. However, analog media are limited in several respects when compared to a print book. First, they are by their nature linear presentations, which leave much to be desired when reading reference works, textbooks, magazines, and other materials that are often accessed randomly. In contrast, digital media offer readers the ability to move around in a book or magazine as freely as (and more efficiently than) a sighted reader flips through a print book. Second, analog recordings do not allow users to interact with the book by placing bookmarks or highlighting material. A DTB offers this capability, storing the bookmarks and highlights separate from, but associated with, the DTB itself. Third, talking book users have long complained that they do not have access to the spelling of the words they hear. As will be explained below, some DTBs will include a file containing the full text of the work, synchronized with the audio presentation, thereby allowing readers to locate specific words and hear them spelled. Finally, analog audio offers readers only one version of the document. If, for example, a book contains footnotes, they are either read where referenced, which burdens the casual reader with unwanted interruptions, or grouped at a location out of the flow of the text, making them difficult for interested readers to access. A DTB allows the user to easily skip over or read footnotes. The Digital Talking Book offers the print-disabled user a significantly enhanced reading experience -- one that is much closer to that of the sighted reader using a print book.

The DTB goes far beyond the limits imposed on analog audio books because it can include not just the audio rendition of the work, but the full textual content and images as well. Because the textual content file is synchronized with the audio file, a DTB offers multiple sensory inputs to readers, a great benefit to, for example, learning-disabled readers. Some visually impaired readers may choose to listen to most of the book, but find that inspecting the images provides information not available in the narrative flow. Others may opt to skip the audio presentation altogether and instead view the text file via screen-enlarging software. Braille readers may prefer to read some or all of the document via a refreshable Braille display device connected to their DTB player and accessing the textual content file.

Digital Talking Books are not tied to a single distribution medium. CD-ROMs will be used first but DTBs will be portable to any digital distribution medium capable of handling the large files associated with digital audio recordings. Regardless of how a DTB is distributed, however, it will normally be in the context of a digital rights management system.

This standard describes the various files that make up a DTB and specifies how each must be formatted. The initiative behind this document grew from a desire to standardize DTB file structures in the hope that it might prevent a recurrence of the multiple formats currently used for talking books throughout the world. This document benefited greatly from the work of the DAISY Consortium, whose members had broken much of the ground covered in this standard and who contributed enormously to the solution of the many problems encountered.

NISO Voting Members

Standards Committee AQ

Standards Committee AQ on Digital Talking Books had the following members at the time this standard was approved:

2. Overview

(This section is informative.)

A digital talking book (DTB) is a collection of electronic files arranged to present information to the target population via alternative media, namely, human or synthetic speech, refreshable Braille, or visual display, e.g., large print. When these files are created and assembled into a DTB in accordance with this standard, they make possible a wide range of features such as rapid, flexible navigation; bookmarking and highlighting; keyword searching; spelling of words on demand; and user control over the presentation of selected items (e.g., footnotes, page numbers, etc.). Such features enable readers with visual and physical disabilities to access the information in DTBs flexibly and efficiently, and allow sighted users with learning or reading disabilities to receive the information through multiple senses. For a full discussion of these capabilities, see the "Document Navigation Features List" [Navigation Features], the user requirements document on which this standard was based. A document written during the development of this standard,Theory Behind the DTBook DTD [DTBook Theory], also describes the navigational capabilities of a DTB in some detail. The content of DTBs will range from audio alone, through a combination of audio, text, and images, to text alone. Section 13 describes these various types of DTBs.

DTB players will also be produced with a variety of capabilities. The simplest might be portable devices with audio-only capabilities. More complex portable players could include text-to-speech capabilities as well as audio output for recorded human speech. The most comprehensive playback systems are expected to be PC-based, supporting visual and audio output, text-to-speech capability, and output to a Braille display. The Playback Device Features List [Player Features] mentioned above presents the committee's priorities for a range of functions across three types of playback devices.

The files comprising a DTB fall into ten categories, as described below:

Package File

The Package File, drawn from the Open eBook Publication Structure 1.0.1, contains administrative information about the DTB and the files that comprise it. A valid XML version 1.0 file, it contains a set of metadata describing the DTB, a list (the manifest) of the files that make up the DTB, and a spine that defines the default reading order of the document. See section 3, "Package File."

Textual Content File

A DTB can contain part or all of the text of the document as an XML 1.0 file marked up in accordance with the document type definition (DTD) defined for this standard,dtbook.dtd. (See Appendix 1, "DTBook DTD.") The textual content file enables properly-configured playback devices to spell words on demand, carry out keyword searches, and permit finely-grained navigation. It can also be accessed directly via refreshable Braille display, synthetic speech, or screen-enlarging software. See section 4, "Content Format for Text."

Audio Files

A DTB can include human or synthetic speech recordings of the document embodied in audio files encoded in one of a specified group of audio formats. Section 5, "Audio File Formats," presents the formats specified by this standard.

Image Files

In addition to text and audio, DTBs can include images that can be presented on players with visual displays. Section 6, "Image File Formats," lists the formats specified by this standard.

Synchronization Files

To synchronize the different media files of a DTB during playback, this standard specifies the use of the World Wide Web Consortium's (W3C) Synchronized Multimedia Integration Language (SMIL), SMIL 2.0 version, an XML 1.0 application. The DTB SMIL files define a sequence of media events. During each event, text elements and corresponding audio clips as well as any additional visual elements are presented simultaneously. DTB players use the synchronization information to both access points in the audio presentation and to track, during audio playback, the corresponding position in the textual content file. This standard uses a subset of the full SMIL 2.0 specification. See section 7, "Synchronization of Media Files," for discussion of these issues and Appendix 2, "DTB-Specific SMIL DTD," for the DTD that defines the DTB SMIL application.

Navigation Control File

The DTB system supports two modes of navigation, global and local.Global navigation -- movement by structure (chapter, section, subsection) and by other selected points such as pages, figures, or notes -- is effected through the Navigation Control file for XML applications (NCX). The NCX presents a dynamic view of the document's hierarchical structure, allowing the user to move through the document in large steps corresponding to its major divisions or in progressively smaller steps down to a limit set by the document's detail. Text, audio, and image elements present to the user the document's headings, and id-based links point to the SMIL presentation at the corresponding locations. Appendix 3 contains the XML 1.0 DTD for the NCX. Local, more finely-grained, navigation is not handled by the NCX but is enabled through the textual content file or SMIL file(s) or through time-based movement through the audio presentation, depending on the document and on the player. See section 8, "Navigation Control File (NCX)," and Appendix 3, "NCX DTD" for specifications related to the NCX.

Bookmark/Highlight File

This standard supports user-set, exportable bookmarks and highlights to which text and audio notes can be applied. Specifications for the XML 1.0 file for portable bookmarks and highlights are presented in section 9, "Portable Bookmarks and Highlights" and Appendix 4, "DTD for Portable Bookmarks/Highlights."

Resource File

The resource file contains or references various text segments, audio clips, and/or images that provide alternative representations of navigational information -- for example, feedback on the user's current location in the document. It supplies information normally presented in a print book via typographical clues. See section 10, "Resource File," and Appendix 5, "DTD for Resource File" for file specifications.

Distribution Information File

Given the great size of audio files even when heavily compressed, it will be common for large books to span several media units. Section 11, "Packaging Files for Distribution," describes how the "distInfo" file maps the location of each SMIL file to a specific media unit, e.g., disk 1 of 3. It also explains how, when several books are distributed on the same media unit, the distInfo file stores information about each book for presentation to the reader. Appendix 6, "Distribution Information DTD," presents the document type definition for "distInfo" files.

Presentation Styles

Section 12, "Presentation Styles," discusses how the presentation of a DTB in various media can be controlled through the use of optional style sheets.

Link to full standard

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Posted on 2011-01-10