Digitization Of The Book: A Report On Present Trends

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• A New Generation of Audio Books
  • 6.1 Overview
  • 6.2 Phase I: Digital Master Production to Support Current and Future Distribution Media
  • 6.2.1 Hard Drive Digital Audio Mastering
  • 6.2.2 Digital Audio Tape (DAT)

A New Generation of Audio Books

6.1 Overview

Today as in the past, the application of audio technology for the production and playback of audio books reflect the dilemma faced by library producers in selecting cost-effective playback systems. Some chose the standard two-track cassette format while others created a closed program requiring special equipment which secures copyright agreements and provides a compact vehicle for storing and distributing audio books.

At present there are three systems used by library producers for distributing audio books. In North America, most are produced in a 4 track nonstandard restricted format, providing 6 hours of playing time per cassette and cannot be played on standard commercial cassette players. This system is used in other parts of the world, including South Africa, the United Kingdom, New Zealand and Australia. In most of Europe the 2 track standard commercial format, limited to 1.5 hours of playback time is used. A third proprietary system, which is used by the Royal National Institute for the Blind (RNIB) in the United Kingdom, utilizes 6 tracks with a capacity of 12 recorded hours per tape.

The advantage of the 4 track and 6 track systems is their compact storage and distribution requirements. An unabridged recorded book of 50 or more recorded hours would require 34 cassettes on the standard two track cassette, but a 4 track copy would use only 9 cassettes. The savings on the distribution and storage, however, are counterbalanced by the costs of purchasing and maintaining specially designed playback equipment. The two track system enjoys all the advantages of the commercial market. Both the playback equipment and the cassettes used are ubiquitous and affordable for the user and can be serviced conveniently and easily.

Concern with the next generation of talking books is growing. Digitized information offers new opportunities to improve present talking book systems to achieve more compact storage and delivery and to index materials for blind students or researchers. As many European libraries for the blind distribute talking books on a commercial 2 track format, they are anxious to make the transformation to a new system using current digital technologies and commercial playback equipment and to be internationally compatible with other library audio book systems. The Danish National Library for the Blind has recently announced a contract with IBM to create a digital library for this purpose.

6.2 Phase I: Digital Master Production to Support Current and Future Distribution Media

Digital mastering of human voice recordings will support both the current system of talking book distribution (audio cassette) and any future digital distribution medium or transmission method. It is anticipated that in 1996 considerably less expensive digital loopbin systems will become available to facilitate audio cassette duplication of talking book copies from CD or DAT masters at a rate faster than real time. Otari is expected to release the OT-DP2 digital loopbin in 1996. Graff Electronic Machines Limited (Nottinghamshire, England) is developing a high speed (16 times real time) digital master to cassette copy duplicator for RNIB. Transfer from a digital master to an analog submaster or copy has up to this point largely been done one-to-one in real time, a time consuming process. These developments will enhance production of analog cassette copies from a digital master.

6.2.1 Hard Drive Digital Audio Mastering

Digital audio files can be produced on MacIntosh or IBM based computers with specifically designed software. There are a number of commercial products available and in use by major commercial production and broadcast agencies. Because uncompressed digital audio files consume disk space, substantial drive capacity is required. Approximately 10 or 11 megabytes of storage space are required for one minute of stereo audio recording (16 bit, 44.1 kHz sampling rate, the commercial standard). Some hard drive systems permit recording at a lower sampling rate, thus reducing the storage capacity requirements for any digital medium. However, as the sampling rate decreases, sound quality decreases, although the effect of minimal levels of degradation are not as profound for the human voice as for music. Most current hard drive systems have been designed for commercial applications, that is, for the creation and editing of small audio files. They do not readily accommodate the alternate format master production environment of libraries for the blind, where massive unabridged audio files are the norm rather than the exception.

Following extensive research and a request for proposal in the commercial market in 1994, The CNIB Library for the Blind acquired the Sonic Solutions Quattro system which accommodates both original mastering, precision digital editing and digital archiving. It has been found to be most effective as an editing tool and has facilitated the enhancing of some audio products. For example, during post production editing 'time codes' or index points can be inserted into the audio file. These codes can be transferred with the audio file, providing index/search points within the final product.

The Royal Blind Society (RBS) in New Zealand is experimenting with the Fairlight MFX3, a commercial hard disk mastering system. As of February 1996 RBS had produced one talking book using this system. The system is capable of a 32kHz sampling rate and RBS has expressed satisfaction with the results, indicating that the software is comparatively user friendly.

Both the Library of Congress, NLS/BPH and RNIB are involved in research and development in this area.

6.2.2 Digital Audio Tape (DAT)

DAT resembles an analog cassette in appearance, and operates linearly, as do cassettes. The technology, however, is quite different. In DAT recording, the audio signal is converted into bytes which are recorded onto the magnetic surface of the tape. The Library of Congress, NLS/BPH, the CNIB Library for the Blind and other producing organizations are currently using this format for some master production. Because it uses magnetic tape, it is not considered to be a viable long term storage medium.