red book

Wednesday, September 27, 2006

Red Book (audio CD standard)

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CD Audio)
Red Book is the standard for audio CDs (Compact Disc Digital Audio system, or CDDA). It is named after one of a set of colour-bound books that contain the technical specifications for all CD and CD-ROM formats.
The first edition of the Red Book was released in June 1980 by Philips and Sony; 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 as per the relevant Philips order form (document no. 28/10/04-3122 783 0027 2) is US$5000. As of 2006, the IEC 908 document is also available as a PDF download for $210

Tuesday, September 26, 2006

Technical details

The Red Book specifies the physical parameters and properties of the CD, the optical "stylus" parameters, deviations and error rate, modulation system and error correction, and subcode channels and graphics.
It also specifies the form of digital audio encoding (2-channel signed 16-bit PCM sampled at 44100 Hz).
Bit rate = 44100 samples/s × 16 bit/sample × 2 channels = 1411.2 kbit/s (more than 10 MB per minute)
Sample values range from -32768 to +32767.
On the disc, the data is stored in sectors of 2352 bytes each, read at 75 sectors/s. Onto this is added the overhead of EFM, CIRC, L2 ECC, and so on, 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/sector × 75 sectors/s = exactly 150 KiB/s = about 8.8 MB per minute.

Monday, September 25, 2006

Copy-protection (C)

Recently, some major recording publishers have begun to sell CDs that violate the Red Book standard for the purposes of copy prevention, using systems like Copy Control, or extra features such as DualDisc, which features a CD-layer and a DVD-layer. The CD-layer is much thinner, 0.9mm, than required by the Red Book, which stipulates 1.2mm. 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, the long-familiar logo is no longer to be seen on recent CDs, as well as stickers and warnings that the CD is not standard and may not play in all CD players.

Sunday, September 24, 2006


With the rise of MP3 players and high-capacity Secure Digital cards the usage of CD's has declined as Digital Audio Players are smaller in terms of physical size, can store more tracks in binary format and don't require the user to carry their CD collection around with them. Online music sites such as iTunes have also contributed to the demise of the CD . Purchasing music on a CD still remains a viable choice for buying new music although due to the decline of portable CD players and the rise of MP3 players users commonly rip the tracks from the CD then archive it, but most often with a loss of sound quality, thus turning sometimes excellent recordings into mediocre sound files.