If you've
ever wondered how a CD player works then we've got good news for you. Forum
member reddish managed to develop an impressive tool. The tool is basically a
software model of a CD player which demonstrates how all bits, read from a disc, are
processed in order to produce music.
As you might know the laser of the CD player reads
pits and lands (0's and 1's) and due to error correction and other information
available at the disc there is a chip that decodes this information and sends
audio to the output of the CD player. Thanks to reddish
this decoding can now be demonstrated using a PC.
using EFM, how to decode & check P/Q/R/S/T/U/V/W subchannels (including an implementation of the Q-channel CRC that ought to make you smile), how to do C1/C2 checking for the audio data, and how to do audio de-interleaving. This is not a finished piece of work by any standard. However, I hope it will prove useful to people trying to understand what goes on deep in the bowels of a CD player. |
The next challenge for reddish will be to stream raw data
(0's and 1's) directly from the laser to the hard drive so he can use his own
software to decode it and send it to the sound card. Note that this is all for
advanced users but very interesting. Read more about laser2wav in the forum thread.
Source: Club CDFreaks
