Audio extraction is purely digital, how could unremarked errors occur?
The data transmission itself is purely digital and also the data stored on the CD. But the Red Book standard (standard for audio CDs) is very weak and only little error correction will be performed in the drive. So on bad CD-ROM drives it is possible that you receive erroneous results.
什么是CD的Red Book Standard？44.1khz 16bit PCM是怎么得来的？
The first edition of the Red Book was released in 1980 by Philips and Sony;it was adopted by the Digital Audio Disc Committee and ratified by the International Electrotechnical Commission Technical Committee 100, as an International Standard.
The audio contained in a CD-DA consists of two-channel signed 16-bit Linear PCM sampled at 44,100 Hz.
The sampling rate is adapted from that attained when recording digital audio on a PAL (or NTSC) videotape with a PCM adaptor, an earlier way of storing digital audio.An audio CD can represent frequencies up to 22.05 kHz, the Nyquist frequency of the 44.1 kHz sample rate.
The selection of the sample rate was based primarily on the need to reproduce the audible frequency range of 20–20,000 Hz (20 kHz). The Nyquist–Shannon sampling theorem states that a sampling rate of more than twice the maximum frequency of the signal to be recorded is needed, resulting in a required rate of at least 40 kHz. The exact sampling rate of 44.1 kHz was inherited from a method of converting digital audio into an analog video signal for storage on U-matic video tape, which was the most affordable way to transfer data from the recording studio to the CD manufacturer at the time the CD specification was being developed.