OS X and iOS Kernel Programming

An Introduction to Digital Audio and Audio Devices

Sound waves are analog by nature, and as we know, analog signals aren't easily stored or manipulated by a computer system that stores and processes information digitally. Other devices, such as CD, DVD, and Blu-Ray players, also operate with digital audio.

Digital audio information is mainly derived from an analog audio wave by a process known as Pulse Code Modulation (PCM). PCM works by sampling or taking a measurement of the analog audio wave at fixed intervals. The number of measurements taken per second is known as the sample rate. Audio on a CD is sampled at 44.1 kHz. Other sources, such as HD video, may use 48 kHz, which means there are 48000 measurements of the audio wave performed per ...