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Originally Posted by Rod_Bod Hi, don't mean to hijack, but I've been wondering a while...
why is "Redbook" called as-such???
Thanks. |
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 sub code channels and graphics.
It also specifies the form of digital audio encoding (2-channel signed 16-bit PCM clocked 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.
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Copy-protection (C)
Recently, some major recording publishers have begun to sell Cd's that violate the Red Book standard for the purposes of copy prevention, using systems like Copy Control, or extra features such as Dual Disc, 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 Cd's, as well as stickers and warnings that the CD is not standard and may not play in all CD players.
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See also