what bit rate are CDs?

[Oscar1613]

Originally posted by: FoBoT
http://www.pcguide.com/ref/cd/formatCDDA-c.html

Data in the CD digital audio format is encoded by starting with a source sound file, and sampling it to convert it to digital format. CD-DA audio uses a sample rate of 44.1 kHz, which is roughly double the highest frequency audible by humans (around 22 kHz.) Each sample is 16 bits in size, and the sampling is done in stereo. Therefore, each second of sound takes (44,100 * 2 * 2) bytes of data, which is 176,400 bytes.

Audio data is stored on the disk in blocks, which are also sometimes called sectors. Each block holds 2,352 bytes of data, with an additional number of bytes used for error detection and correction, as well as control structures. Therefore, 75 blocks are required for each second of sound. On a standard 74-minute CD then, the total amount of storage is (2,352 * 75 * 74 * 60), which is 783,216,000 bytes or about 747 MB. From this derives the handy rule of thumb that a minute of CD audio takes about 10 MB, uncompressed.

winnAr

 

[CalvinHobbes]

Originally posted by: kravmaga
CD's don't have a bitrate either. They are 44.1hz uncompressed digital. DVD's Dolby Digital is 192kbs and sounds like crap while DTS is around 600-800kbs VBR and sounds much better.

Compact Disc uses roughly 706kbps (kilobits per second) to reproduce one uncompressed 16-bit linear PCM audio channel.

In the home, Dolby Digital 5.1 normally operates at either 384kbps or 448kbps (Dolby Digital's maximum bitrate on DVD-Video), but can operate at bitrates as low as 224kbps as used on some IMAX DVDs, or as high as 640kbps.

DTS runs at 882kbps in its theatrical application and 1235kbps on LaserDisc/CD (please note: DTS's domestic and theatrical variants do not use the same audio codec), and 1509kbps or 754kbps on DVD.

Dolby Digital and DTS are capable of using sampling frequencies of 32, 44.1, or 48kHz (DTS can also function at up to 192kHz).