Path: utzoo!utgpu!watmath!clyde!bellcore!rutgers!apple!bionet!agate!violet.berkeley.edu!izumi
From: izumi@violet.berkeley.edu (Izumi Ohzawa)
Newsgroups: comp.sys.next
Subject: Re: Voice Mail Format -- I sure hope this isn't final.
Keywords: voice mail
Message-ID: <18109@agate.BERKELEY.EDU>
Date: 10 Dec 88 02:02:28 GMT
References: <19355@ames.arc.nasa.gov> <21949@apple.Apple.COM>
Sender: usenet@agate.BERKELEY.EDU
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Organization: University of California, Berkeley
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In article <21949@apple.Apple.COM> desnoyer@Apple.COM (Peter Desnoyers) writes:
>In article <19355@ames.arc.nasa.gov> bhine@nike.UUCP (Butler Hine  sst) writes:
>>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 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. 
>				Peter Desnoyers

Are you sure that this is the format NeXT voice mail is transmitted
over the net?  I grabbed that file, and it was HUGE.
At 8 kbytes/second of voice, I am not sure if anyone can tolerate
the traffic.

A lot of foreign e-mail addressees pay  $$$ per kilobyte of
messages RECEIVED and transmitted.  I think Japanese users pay
something like $1.00/kilobyte.  That comes to $8/second!

Also, with straight PCM, the much touted DSP chip isn't necessary.
Surely, something like LPC (linear prediction coding) or PARCOR
(I forgot what that stands for) can be implemented easily with
the DSP chip.

Izumi Ohzawa
izumi@violet.berkeley.edu
...ucbvax!violet!izumi