Digitization Of The Book: A Report On Present Trends

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• Conclusion
• Glossary

Conclusion

The digitization of the book presents new opportunities for information equity for those unable to read print. The technology required is expensive, but it is a growing necessity for those who depend on it to make information accessible.Yet for all people, regardless of ability to read standard print, technology poses a potential inequity, a different kind of barrier.

"The Information Superhighway threatens to widen a gulf between the information-rich and -poor...That's where libraries come in. Libraries have served as the nation's great equalizer [in the dissemination of information]." ³

The challenge for organizations serving print handicapped individuals is to ensure that these technologies do not become a barrier and people are provided with the material they need in the format they need, regardless of their ability to work with or afford access equipment.

ANALOG

One-to-one representation; sound is translated within a microphone into a pulsed electrical signal; when played back from the storage medium (vinyl record, magnetic tape), this signal vibrates a speaker membrane which produces audio resembling the original audio signal

BANDWIDTH

(CARRIER & 'SENDER', in relation to transmission of data) Cable's capacity level to carry/transmit data; 'copper pair' ('twisted pair') cable is low capacity (standard telephone lines), coaxial cable has greater capacity than copper pair, and optical cable has even greater capacity (toslink is a fibre optic cable, glass cable has a higher bandwidth than toslink); the greater the bandwidth, the greater the cable's capacity for transmission of data, both in terms of number of signals which can be carried and speed of transmission; expressed in kilobits/second; Receiver/Sender's (modem's) capacity level to send or receive data

BIT

A binary digit; the smallest unit of digital information; there are 1,000 bits in a kilobit and one million bits in a megabit

8-BIT, 16-BIT, 24-BIT

The number of bits a computer's CPU can handle at a time; the larger the number, the more complex the information that can be handled (eg: a 3-bit processor can generate sound with a 45dB dynamic range, a 16-bit processor can handle 90dB of dynamic range)

BIT RATE

A measure of the units of information being transferred over time; the bit rate of a CD quality stereo signal is 1.4 Mbit/second; the US telephone system bit rate is 56 kbit/s.

BYTE

Eight binary digits, containing 256 possible patterns of 1's and 0's; there are 1,000 bytes in 1 megabyte and 1,000 megabytes in 1 gigabyte

CD

(CD-DA) Compact disc-digital audio; a storage medium for holding information; 5.25 inches in diameter; manufactured to be played on a commercial CD player; can also be played on a computer with a CD-ROM drive; recorded by converting analog signals into digital samples usually at the rate of 44.1 kHz (44,100 samples per second) of 16-bit stereo digital audio; usually contains audio only

CD-PLUS

(CD+) a new standard developed jointly by Philips and Sony that will make it possible to play the audio portion of mixed data/audio/video CDs on a standard CD-audio player

CD-R

Compact disc recordable; a write-once CD system (WORM); requires a CD-R drive to write to the disc; some can also be used in CD players

CD-ROM

Compact disc, as above; manufactured to be played on a CD-ROM drive which uses a different set of custom designed integrated circuits to accommodate a requirement for greater accuracy; audio portions can be played on a commercial CD player, other data cannot; may contain sound and visual images as well as electronic text (also, CD-ROM with video, which requires a different player to accommodate the video portion; disc spins at a greater speed, 4 - 6 times faster than yellow book standard CD-ROM)

COMPRESSION

An algorithm which systematically removes 'bits' of the data from the digitized audio; the 'bits' which are taken out may be periods of silence (minimal signal), vowel sounds or consonant sounds, dependant upon the particular algorithm; all degrade the signal to some extent, but elimination of consonant sounds is the most negative form; the greater the compression, the greater the loss of sound quality; the greater the compression, the smaller the bandwidth required to transmit the signal; encoding and decoding are related to the specific algorithm; two proprietary coding schemes are AC-2, developed by Dolby labs, and apt-X100. The third, the ISO standard, is MPEG

CPU

Central Processing Unit (within a computer) determining the computer's power and speed; the CPU performs the data processing

DAISY

Digital Audio based Information SYstem

DIGITAL

An analog signal (electrical impulses) converted into numerical data by an analog to digital converter (ADC); a digital to analog converter (DAC) converts the numerical data back into electrical signals

DSD

Direct Stream Digital; developed by Sony; a new master recording system whose recording parameters are wide enough to embrace existing and future media formats; 16, 20 and 24-bit are available; 100 kHz sampling frequency with 140 db dynamic range; supports Red Book CD; able to provide enhanced restoration of archived material

DVD

High density disc/Digital Video Disc, also known as Digital Versatile Disc; new format released in early 1996; large storage capacity, depending upon format/version, has a 4.7 (single layer, one side) to 17 (dual layer, 2 sides) gigabyte capacity; designed to carry MPEG 2 or AC-3 encoded variable-rate video with lossy-compressed audio

EBU

European Blind Union

GIGABYTE

See Byte

HQAD

High Quality Audio Disc; DVD which is to be used for audio only; an application proposed by ARA (Acoustic Renaissance for Audio) based on the DVD/SD/MMCD format; multi channel rather than mono or stereo; intended to optimize audio quality on DVD up to six channels with 24-bit resolution and 96 kHz sampling frequency

ISDN

Integrated Services Digital Network; new telecommunications standard for very high speed data transfer

kHz

Kilohertz; a measure of sampling frequency equivalent to 1,000 cycles per second

LC/NLS/BPH

Library of Congress, National Library Service for the Blind and Physically Handicapped

LOSSLESS COMPRESSION

A process by which the data of a PCM audio signal can be more efficiently packed into a channel (less storage space is required); these compression systems return the input data exactly when it is decoded (uncompressed); lossless coding does not alter the final decoded transmitted signal in any way, rather, it 'packs' the audio data more efficiently into a smaller data rate

LOSSY COMPRESSION

The 'bits' of data that have been removed from the digitized audio are 'lost'; they are not restored when the file is decoded (uncompressed); the decoded data is not identical to the original input signal; in the best case scenario, the difference would not be audibly detectable, in the worst case scenario, distortion, fuzziness, etc. would result; it is a process by which an audio signal is examined from a human-psychoacoustic viewpoint; the algorithm attempts to estimate and remove the inaudible components of the signal

MEGABYTE

See Byte

MINI DISK

Re-recordable magneto-optical disk 63.5mm in diameter

MODEM

Modulator-Demodulator; a device which converts computer data to a form which can be transmitted by telephone networks

NLS/BPH

See LC

OCR

Optical Character Recognition; the conversion of typewritten data to computer format via 'intelligent' computer application

OPTICAL JUKE BOX

Digital storage system; write once, read many

PCM

Pulse Code Modulation; a method of coding in which a signal is represented by a discrete-sampled series; the basis for most digital audio systems

MPEG

"Motion Picture Experts Group"; one standard for compression, developed to meet the needs of the motion picture industry; MPEG layer 1 (old technology), MPEG-2, and MPEG-3 and MPEG-4 (layer 4 is still in development); the complexity of the encoder and decoder is indicated by the 'layer'; MPEG standards do not specify what process must be used to encode data, rather, they specify what a bitstream is to look like and how it must be decoded; MPEG is lossy type compression; some CD-ROM drives have MPEG compression/decompression built into them

RFB & D

Recording for the Blind and Dyslexic, based in the United States

SAMPLING RATE

The number of times the audio is 'sampled' per second; 8 kHz = 8,000 samples per second; range: 8 kHz - 100 kHz; at low sampling rates the accuracy of the reproduction suffers and the sound becomes 'fuzzy'; the higher the sampling rate, the greater the accuracy

SCMS

Serial Copy Management System; a copy-inhibit system which prevents the digital copy of an original recording being copied itself in the digital domain

SCSI

Small computer systems interface; one of two common interfaces (the other being IDE)

tpb

Swedish Library of Talking Books and Braille

Technical Notes

bit 32 kHz, 6 to 1 compression = FM radio equivalent

Red Book, Yellow Book, Green Book and Orange Book

Standards which determine specifications for storage and delivery of information; developed in an attempt to maintain compatibility across a wide range of products; all are based on the Red Book standard for audio CDs

Yellow Book

Defines the physical properties of the discs, the arrangement on the spiral, the speed at which they are read, error correction, and sector size. It also sets two data modes to determine how text and computer data are handled. Yellow Book mode 1 specification provides the best possible error correction. An audio CD player reads only Red Book tracks, while CD ROM players can read Yellow Book tracks. CDPlus (CD Extra) adheres to the Blue Book standard, which reads Red Book plus Yellow Book

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