LPCM

Linear pulse-code modulation (LPCM) is a method of converting an analog audio signal into a digital representation by sampling the signal at regular intervals and quantizing each sample with a fixed number of bits using a linear quantization scale. In LPCM, the quantization levels are evenly spaced, meaning the full-scale range is divided into equally sized steps. This is in contrast to companded forms such as mu-law or A-law.

Common bit depths include 16, 24, or 32 bits per sample, and common sampling rates include 44.1 kHz, 48 kHz, 96 kHz, and higher. The resulting data rate depends on the number of channels and rate. LPCM is uncompressed, so there is no perceptual compression; the reconstructed signal is a faithful reproduction of the sampled analog waveform within the quantization limits and hardware accuracy.

Use cases include compact discs (CDs) with 16-bit/44.1 kHz PCM, digital video and cinema, Blu-ray discs, DVDs, and many professional audio interfaces and digital audio workstations. It is also widely used in HDMI and S/PDIF digital audio connections as the default uncompressed format. LPCM can be mono, stereo, or multichannel (5.1, 7.1 and beyond).

Advantages of LPCM include simple decoding, broad compatibility, and high fidelity when paired with adequate bit depth and sampling rate. Limitations include large file sizes and bandwidth requirements compared with compressed formats. Some professional applications allow 32-bit floating-point PCM for greater dynamic range and headroom.