Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!apple!desnoyer
From: desnoyer@Apple.COM (Peter Desnoyers)
Newsgroups: comp.sys.next
Subject: Re: Voice Mail Format
Keywords: voice mail
Message-ID: <21949@apple.Apple.COM>
Date: 9 Dec 88 02:13:30 GMT
References: <19355@ames.arc.nasa.gov>
Distribution: na
Organization: Apple Computer Inc, Cupertino, CA
Lines: 24

In article <19355@ames.arc.nasa.gov> bhine@nike.UUCP (Butler Hine  sst) writes:
>[gobble]
>
>I kept the sample of NeXT voice mail sent out a while ago, but I never
>saw any explanation of the format.  Does anyone know what the format is?
>I saw a note from someone saying they had decoded it, but I can't find
>their address.  Help!  Thanks in advance.
>
>			Butler Hine
>			NASA Ames Research Center
>			hine@galileo.arc.nasa.gov

I posted that message. The format is simple, like uuencoded data but
just a hair different. The binary data is standard mu-law PCM voice at
8k samples/second, with 8 bit samples. 

the ascii format is lines of:
abcdabcd...(64chars)

where each group of 4 characters ('abcd') decodes to 3 bytes as
follows: subtract 33 (decimal) from each character to get a 6-bit
value. Concatenate 4 6-bit values to get 3 8-bit values.

				Peter Desnoyers