A process or device that converts digital audio from one sample rate to another. Normally when audio plays back at a different sample rate from which it was recorded, the pitch of the audio will change. A sample rate converter must change the rate at which the samples occur without changing the pitch or introducing any other degradation. This is very difficult to do well because it involves adding additional or (usually) removing data from the bit stream. Historically, the resulting audio from such a process was less than desirable, and was a major factor in the decision of many engineers to capture (record) their audio at the sample rate of the delivery medium (usually CD at 44.1 kHz). Nowadays many converters are much better. Sample rate conversion is now part of the every day life of many engineers and is considered a viable part of the production process (assuming a high quality process is used).