Red_book_(audio_cd_standard)

For other uses, see Red Book.

Red Book (audio CD standard)
Media type	Optical disc
Encoding	2 channels of PCM audio, each signed 16-bit values sampled at 44100 Hz
Capacity	up to 700 MB
Read mechanism	780 nm wavelength semiconductor laser
Developed by	Sony & Philips
Usage	Audio and data storage

Red Book is the standard for audio CDs (Compact Disc Digital Audio system, or CDDA). It is named after one of a set of color-bound books that contain the technical specifications for all CD and CD-ROM formats.

The first edition of the Red Book was released in 1980 by Philips and Sony;How the CD was developed. BBC News (August 17, 2007). Retrieved on 2007-08-17. it was adopted by the Digital Audio Disc Committee and ratified as IEC 908. The standard is not freely available and must be licensed from Philips. At the time of writing, the cost per the relevant Philips order form Document no. 28/10/04-3122 783 0027 2 is US$5,000. As of 2006, the IEC 908 document is now known as IEC 60908 and is also available as a PDF download for $242.http://webstore.ansi.org/ansidocstore/product.asp?sku=IEC+60908+Ed.+2.0+b%3A1999

Redbook Audio Specifications

The basic specifications state that

1. Maximum playing time is 78 minutes (including pauses)
2. Minimum duration for a track is 4 seconds
3. Maximum number of tracks is 99
4. Maximum number of index points (subdivisions of a track) is 99 with no maximum time limit
5. International Standard Recording Code (ISRC) should be recorded on CD-Rs to appear on the replicated discs

Technical details

The pits in a CD are 500 nm wide, between 830 nm and 3,000 nm long and 150 nm deep.

The Red Book specifies the physical parameters and properties of the CD, the optical "stylus" parameters, deviations and error rate, modulation system (Eight-to-Fourteen Modulation, EFM) and error correction (Cross-interleaved Reed-Solomon coding, CIRC), and subcode channels and graphics.

It also specifies the form of digital audio encoding: 2-channel signed 16-bit PCM sampled at 44,100 Hz.

An audio CD can represent frequencies up to 22.05 KHz — the Nyquist frequency of the 44.1 KHz sample rate.

The bit rate is 1411.2 kbps:

44,100 samples per second × 16 bits per sample × 2 channels × 1 kilobit/1000 bits = 1411.2 kbps.

Sample values range from -32768 to +32767.

On the disc, the data is stored in sectors of 2352 bytes each, read at 75 sectors per second. Onto this the overhead of EFM, CIRC, L2 ECC, and so on, is added, but these are not typically exposed to the application reading the disc.

By comparison, the bit rate of a "1x" data CD is defined as 2048 bytes per sector × 75 sectors per second = 150 KiB/s, or approximately 9.2 million bytes per minute.

Copy prevention

Some major recording publishers have begun to sell CDs that violate the Red Book standard. Some do so for the purpose of copy prevention, using systems like Copy Control.

Some do so for extra features such as DualDisc, which includes both a CD-layer and a DVD-layer whereby the CD-layer is much thinner, 0.9 mm, than required by the Red Book, which stipulates a nominal 1.2 mm, but at least 1.1 mm. Philips and many other companies have warned them that including the Compact Disc Digital Audio logo on such non-conforming discs may constitute trademark infringement. Either in anticipation or in response, recent copy-protected CDs bear stickers and warnings that the CD is not standard and may not play in all CD players, and no longer display the long-familiar logo.

See also

• Extended Copy Protection — source of the Sony DRM scandal
• DRM (computing)
• Four-channel compact disc digital audio

External links

• Philips\' Audio Standards licensing info
• IEC 60908 publication info

References

This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia