What is a u-law (pronounced “mew-law”) file?
u-law is a non-linear coding system used by the telephone company to transmit audio in a digital format. u-law operates at 8,000 samples per second in an 8-bit format. Because this is a logarithmic format, it is more efficient than linear coding formats, such as the popular .WAV format. u-law encoding is technically not a form “compression”. Rather, it is a way of adjusting the sampling characteristics of the Analog-to-Digital conversion process to match the logarithmic sensitivity of the human ear. u-law encoding is typically referred to as “companding”. When an 8 bit u-law sample is sent, one bit is used to give the polarity of the signal (1 for positive, 0 for negative). The remaining 7 bits correspond to the logarithmic quantization of the sample. An 8-bit u-law file offers performance equivalent to a 14 bit linear file. The less efficient .WAV file format is the most common audio format used in transferring audio between PCs.
