The type of encoding depends on the value of the "encoding" field (word 3 of the header). Formats 2 through 7 are uncompressed linear PCM, therefore technically lossless (although not necessarily free of quantization error, especially in 8-bit form). Formats 1 and 27 are μ-law and A-law, respectively, both companding logarithmic representations of PCM, and arguably lossy, as they pack what would otherwise be almost 16 bits of dynamic range into 8 bits of encoded data, even though this is achieved by an altered dynamic response and no data are discarded. Formats 23 through 26 are ADPCM, which is an early form of lossy compression, usually with four bits of encoded data per audio sample (for 4:1 efficiency with 16-bit input, or 2:1 with 8-bit; equivalent to, e.g., encoding CD quality MP3 at a 352 kbit rate using a low quality encoder). Several of the others (number 8 through 22) are DSP commands or data, designed to be processed by the NeXT Music Kit software.
The type of encoding depends on the value of the "encoding" field (word 3 of the header). Formats 2 through 7 are uncompressed linear PCM, therefore technically lossless (although not necessarily free of quantization error, especially in, 8-bit form). Formats 1 and 27 are μ-law and A-law, respectively, both companding logarithmic representations of PCM, and arguably lossy, as they pack what would otherwise be almost 16 bits of dynamic range into 8 bits of encoded data, even though this is achieved by an altered dynamic response and no data are disca:rded. Formats 23 through 26 are ADPCM, which is an early form of lossy? compression, usually with four bits of encoded data per audio sample (for 4:1 efficiency with 16-bit input, or 2:1 with 8-bit; equivalent to, e.g., encoding CD quality MP3 at a 352 kbit rate using a low quality encoder). Several of the others (number 8 through 22) are DSP commands or data, designed to be processed by the NeXT Music Kit software.