Pulse Code Modulation.  PCM is the most basic form of representing an analog signal as a digital signal.  PCM is commonly used to create digital audio signals from analog audio.  The signal is sampled at regular intervals to determine the signal amplitude.  CD Audio (Red Book) uses PCM Audio on 2 channels (stereo), with 16 bit sampling at 44.1 kHz.  In other words, both the left and right audio channels are sampled 44,100 times per second, and the analog amplitude is represented as a digital value that has a decimal equivalent of 0 to 65535.  DVD-Video provides mandatory support for PCM audio, at a minimum sampling frequency of 48 kHz, 2 channels, with 16 bit resolution.  DVD-Video can include up to 8 channels of PCM audio, at up to 96 kHz sampling frequency, and either 16, 20, or 24 bit resolution (quantization), with a maximum total bitrate of 6.144 Mbit/sec.