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DTB (Digital Talking Book), 2005

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Digital Talking Book. ANSI/NISO Z39.86-2005
Description

The NISO Digital Talking Book Standard, ANSI/NISO Z39.86-2005, 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.

The standard comprises a set of files, including a mandatory package file, which incorporates a manifest listing all the other component files and a spine, which indicates logical reading order. Component files can be of several types, including: a mandatory navigation control file (in XML); textual content (in XML); audio files; image files; synchronization files (in SMIL); bookmark/highlight files (in XML).

Production phase This bundle of files is likely to be used primarily as a middle-state format, with dissemination to end-users managed through publishers or aggregators who provide in a form appropriate for viewers/players that enforce limitations on access and use consistent with terms imposed by copyright holders.
Relationship to other formats
    Has earlier version DTB_2002, DTB (Digital Talking Book), 2002. DAISY/NISO
    Contains OEBPS_1_0, OEBPS, Open Ebook Forum Publication Structure 1.0.1
    Defined via XML_DTD, XML Document Type Definition (DTD)
    May contain WAVE_LPCM, WAVE Audio File with LPCM Audio
    May contain MP3_ENC, MP3 Audio Encoding
    May contain AAC_MP4, Advanced Audio Coding (MPEG-4)
    Used by EPUB_2, Electronic Publication, Version 2

Local use Explanation of format description terms

LC experience or existing holdings The National Library Service for the Blind and Physically Handicapped (NLS), which is part of LC, has been actively involved in the development of this standard. The unit employs an extended version of the 2002 version of the DAISY/NISO standard, DTB_2002_NLS.
LC preference Preferred format for digital talking books. A DTB (2002 or 2005 versions) incorporating the full text of a work is among the preferred XML-based formats for textual works.

Sustainability factors Explanation of format description terms

Disclosure Open standard. Specification freely downloadable.
    Documentation ANSI/NISO Z39.86-2005. Specifications for the Digital Talking Book ISSN: 1041-5653
Adoption Not investigated for this version at this time. See DTB_2002.
    Licensing and patents None associated with the package format.
Transparency See DTB_2002.
Self-documentation The Package file can include Dublin Core metadata and an extended set of elements intended to record information about rights and the provenance and generation of the talking book from a source text.
External dependencies None. The format is designed to support effective use of special hardware and software players for the visually impaired, but does not require them.
Technical protection considerations None in relation to the sets of files that comply with the ANSI/NISO Z39.86-2005 specification. Digital Talking Books are likely to be distributed to end users via mechanisms that do impose technical protections. Hence it is probable that LC will need to receive such files direct from publisher or aggregator by a special transmittal process rather than by harvesting as if an end user.

Quality and functionality factors Explanation of format description terms

Sound
Normal rendering Good support.
Fidelity (high audio resolution) Not intended for audio quality beyond CD quality. DTB players must support sample rates of 44.1, 22.05, and 11.025 kHz at a depth of 16 bits per sample. Compressed audio must be encoded such that the output sampling rate is restricted to one of the above three rates and uses a constant bit rate.
Multiple channels DTB Players are not required to support multiple channels, but must recognize stereo and render at least as monaural.
Support for user-defined sounds, samples, and patches No support.
Functionality beyond normal rendering Synchronization with text transcription.
Text
Normal rendering Good support.
Integrity of document structure The logical structure of a document is an important part of a DTB with textual content. See archived DAISY Structure Guidelines for DTB 2005.
Integrity of layout and display This standard focuses on the textual content, the logical structure, and the synchronization of text with audio of the text being read. Layout is not of primary significance in rendering for the visually impaired.
Support for mathematics, formulae, etc. Not supported
Functionality beyond normal rendering Supports embedding of audio, images, and synchronization of text with audio of the text being read.

File type signifiers Explanation of format description terms

Tag Value Note
Filename extension opf
For the required Package file. Documented in DAISY/NISO standard. Extensions and Internet Media Types listed below are for files commonly found in a Digital Talking Book container and listed in the manifest that is in the package file.
Internet Media Type text/xml
Documented in DAISY/NISO standard.
Tag Value Note
Filename extension xml
For textual content files (dtbook). Documented in DAISY/NISO standard.
Internet Media Type application/x-dtbook+xml
Documented in DAISY/NISO standard.
Tag Value Note
Filename extension ncx
For navigation control files (NCX). Documented in DAISY/NISO standard.
Internet Media Type application/x-dtbncx+xml
Documented in DAISY/NISO standard.
Tag Value Note
Filename extension mp4
For AAC_MP4 audio files. Documented in DAISY/NISO standard.
Internet Media Type audio/mpeg4-generic
Documented in DAISY/NISO standard.
Tag Value Note
Filename extension mp3
For MP3 audio files. Documented in DAISY/NISO standard.
Internet Media Type audio/mpeg
Documented in DAISY/NISO standard.
Tag Value Note
Filename extension wav
For WAVE_LPCM audio files. Documented in DAISY/NISO standard.
Internet Media Type audio/x-wav
Documented in DAISYNISO standard.

Notes Explanation of format description terms

General See DTB_2002.
History See DTB_2002 for history through 2002 version. See the September 2005 Road Map to Implementation of DAISY.

The 2005 version of the standard uses SMIL 2 and richer XML markup for the textual content. Some of the other more significant enhancements were: producer-controlled pauses, to allow a DTB author to cause the presentation to pause at specified points and wait for a user action, appropriate for use in workbooks; a more robust method of ensuring that players can maintain their location when navigation methods are mixed; a cleaner mechanism for enabling direct access to pages; and a more efficient method of identifying individual books when more than one is present on a single piece of media. Individual changes made to the standard are described in comments that can be viewed by reading the HTML version in an HTML authoring tool or with a text editor.

In August 2008, the NISO membership approved the creation of a new working group to revise the 2005 version of the standard.


Format specifications Explanation of format description terms


Useful references

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Last Updated: 11/23/2013