When that difference occurs, it can cause the CD player to not open the WAV file or at a minimum it has to be told the format of the audio data for playback purposes. As all recorded data on a CD is stored in digital format for one to listen to it, it must be converted back to analog information. Within the sound card, an analog signal is then converted into digital data which produces its own set of problems. Analog to digital conversion is a tougher engineering problem than converting from digital to analog. Another key factor in determining quality of encoded audio data on a CD is the quality of reading.
Some errors derive from the way the track is formed on the disc and are related to the term jitter .
In addition, the faster the data flies past the laser pickup, the greater the chance that a bit will be misinterpreted. Buffer Underruns Buffer underrun means that the buffer supplying data to the writer has emptied before the data was completely written. Consequently often times the CD reader does not perform at the speed it was expected to deliver. One reason for this is consistently high error rates typical of the CD-R which is scratched or a dirty pressed disc. A second factor which can slow the CD-ROM reader is a severe scratch or similar localized damage which causes it to read most of the time but to have trouble in one area.