From janssen@parc.xerox.com Mon Jan 18 15:07:09 1993 From: janssen@parc.xerox.com (Bill Janssen) Newsgroups: alt.binaries.sounds.d Subject: Sun & Next Audio Format Date: 23 Oct 91 17:43:18 GMT Organization: Xerox PARC, Palo Alto, CA The following is supposedly the sound format used by Sun and Next machines: [ From: mrose@dbc.mtview.ca.us (Marshall Rose) ] Audio data is encoded in three parts: a header, containing fields that describe the audio encoding format; a variable-length information field, in which, for instance, ASCII annotation may be stored; and, the actual encoded audio. The header and data fields are written using big-endian ordering. The header part consists of six 32-bit quantities, in this order: longword field description -------- ----- ----------- 0 magic number the value 0x2e736e64 (ASCII ".snd") 1 data offset the offset, in octets, to the data part. The minimum valid number is 24 (decimal). 2 data size the size in octets, of the data part. If unknown, the value 0xffffffff should be used. 3 encoding the data encoding format: value format 1 8-bit ISDN u-law 2 8-bit linear PCM [REF-PCM] 3 16-bit linear PCM 4 24-bit linear PCM 5 32-bit linear PCM 6 32-bit IEEE floating point 7 64-bit IEEE floating point 23 8-bit ISDN u-law compressed using the CCITT G.721 ADPCM voice data encoding scheme. 4 sample rate the number of samples/second (e.g., 8000) 5 channels the number of interleaved channels (e.g., 1) The information part, consists of 0 or more octets, and starts 24 octets after the beginning of the header part. The length of the information part is calculated by subtracting 24 (decimal) from the data offset field in the header part. -- Bill Janssen janssen@parc.xerox.com (415) 812-4763 Xerox Palo Alto Research Center FAX: (415) 812-4777 3333 Coyote Hill Road, Palo Alto, California 94304