Linear pulse-code modulation
) is a method of encoding audio information digitally. The term also refers collectively to formats using this method of encoding. The term pulse-code modulation
(PCM), though strictly more general, is often used to describe data encoded as LPCM.
LPCM is a particular method of pulse-code modulation which represents an audio waveform
as a sequence of amplitude values recorded at a sequence of times. LPCM is PCM with linear quantization
LPCM represents sample amplitudes on a linear scale. LPCM specifies that the values stored are proportional to the amplitudes, rather than representing say the logarithm of the amplitude (e.g., companding
), or being related in some other manner (e.g., DPCM
). In practice these values will be quantized.
LPCM audio is coded using a combination of various parameters – such as resolution/sample size (e.g., 8, 16, 20, 24 bit, etc), frequency/sample rate
(e.g., 8,000, 11,025, 16,000, 22,050, 24,000, 32,000, 44,100, and 48,000 Hz / "samples per second", etc), sign
(signed or unsigned), number of channels (monaural, stereo
, quadrophonic, etc) and interleaving of channels, byte order
(little endian, big endian). If the sample is 16-bit signed, the sample range is from −32768 to... Read More