Unix Audio (.au) files are UNIX-generated sound files. AU is a sound file format developed by Sun for the Unix platform for use on the Internet. It is known as the Sparc-audio or u-law format and was common on NeXT systems and on early web pages. Originally it was headerless, being simply 8-bit law-encoded data at an 8000 Hz sample rate. Hardware from other vendors often used sample rates as high as 8192 Hz, often integer factors of video clock signals. Newer files have a header that consists of six 32-bit words, an optional information chunk and then the data (in big endian format).